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Cover Page - USD ($) $ in Millions	12 Months Ended
Cover Page - USD ($) $ in Millions	Dec. 31, 2019	Feb. 15, 2020	Jun. 28, 2019
Document Information [Line Items]
Entity Registrant Name	CASELLA WASTE SYSTEMS, INC.
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Entity Central Index Key	0000911177
Current Fiscal Year End Date	--12-31
Entity File Number	000-23211
Entity Filer Category	Large Accelerated Filer
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	03-0338873
Title of 12(b) Security	Class A common stock, $0.01 par value per share
Trading Symbol	CWST
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Shell Company	false
Amendment Flag	false
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Address, Address Line One	25 Greens Hill Lane
Entity Address, City or Town	Rutland
Entity Address, State or Province	VT
Entity Address, Postal Zip Code	05701
City Area Code	(802
Local Phone Number	775-0325
Entity Public Float			$ 1,765
Documents Incorporated by Reference	Part III of this Annual Report on Form 10-K incorporates by reference information from the definitive Proxy Statement for the registrant’s 2020 Annual Meeting of Stockholders or a Form10-K/A to be filed with the Securities and Exchange Commission not later than 120 days after the registrant’s fiscal year ended December 31, 2019
Class A Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		46,803,112
Class B Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		988,200

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
CURRENT ASSETS:
Cash and cash equivalents	$ 3,471	$ 4,007
Accounts receivable, net of allowance for doubtful accounts of $1,468 and $931, respectively	80,205	74,937
Refundable income taxes	1,251	2,254
Prepaid expenses	8,994	7,345
Inventory	7,679	6,542
Other current assets	1,213	2,008
Total current assets	102,813	97,093
Property, plant and equipment, net	443,825
Property, plant and equipment, net		404,577
Operating lease right-of-use assets	108,025
Goodwill	185,819	162,734
Intangible assets, net	58,721	34,767
Restricted assets	1,586	1,248
Cost method investments	11,264	11,264
Deferred income taxes	8,577	9,594
Other non-current assets	11,552	11,133
Total assets	932,182	732,410
CURRENT LIABILITIES:
Current maturities of debt	4,301	2,298
Current operating lease liabilities	9,356
Accounts payable	64,396	57,289
Accrued payroll and related expenses	14,375	10,969
Accrued interest	2,041	2,415
Contract liabilities	2,299	3,074
Current accrued capping, closure and post-closure costs	10,223	11,633
Other accrued liabilities	23,598	23,819
Total current liabilities	130,589	111,497
Debt, less current portion	509,021	542,001
Operating lease liabilities, less current portion	70,709
Accrued capping, closure and post-closure costs, less current portion	61,704	61,442
Deferred income taxes	2,643	2,519
Other long-term liabilities	34,763	30,783
COMMITMENTS AND CONTINGENCIES
Casella Waste Systems, Inc. stockholders' equity (deficit):
Additional paid-in capital	485,332	373,716
Accumulated deficit	(357,016)	(388,669)
Accumulated other comprehensive loss, net of tax	(6,041)	(1,308)
Total stockholders' equity (deficit)	122,753	(15,832)
Total liabilities and stockholders' equity (deficit)	932,182	732,410
Class A Common Stock
Casella Waste Systems, Inc. stockholders' equity (deficit):
Common stock	468	419
Class B Common Stock
Casella Waste Systems, Inc. stockholders' equity (deficit):
Common stock	$ 10	$ 10

CONSOLIDATED BALANCE SHEETS (Parenthetical) $ in Thousands	12 Months Ended
CONSOLIDATED BALANCE SHEETS (Parenthetical) $ in Thousands	Dec. 31, 2019 USD ($) vote $ / shares shares	Dec. 31, 2018 USD ($) vote $ / shares shares
Accounts receivable - trade, allowance for doubtful accounts \| $	$ 1,468	$ 931
Property, plant and equipment, accumulated depreciation and amortization \| $	$ 844,874
Property, plant and equipment, accumulated depreciation and amortization \| $		$ 878,701
Class A Common Stock
Common stock, par value (in dollars per share) \| $ / shares	$ 0.01	$ 0.01
Common stock, authorized shares	100,000,000	100,000,000
Common stock, issued shares	46,803,000	41,944,000
Common stock, outstanding shares	46,803,000	41,944,000
Common stock, votes (in votes per share) \| vote	1
Class B Common Stock
Common stock, par value (in dollars per share) \| $ / shares	$ 0.01	$ 0.01
Common stock, authorized shares	1,000,000	1,000,000
Common stock, issued shares	988,000	988,000
Common stock, outstanding shares	988,000	988,000
Common stock, votes (in votes per share) \| vote	10	10

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Revenues	$ 743,290,000	$ 660,660,000	$ 599,309,000
Operating expenses:
Cost of operations	508,656,000	453,291,000	405,188,000
General and administration	92,782,000	84,791,000	79,243,000
Depreciation and amortization	79,790,000	70,508,000	62,102,000
Southbridge Landfill closure charge, net	2,709,000	8,054,000	65,183,000
Withdrawal costs - multiemployer pension plan	3,591,000	0	0
Expense from acquisition activities and other items	2,687,000	1,872,000	176,000
Contract settlement charge	0	2,100,000	0
Development project charge	0	311,000	0
Total operating expenses	690,215,000	620,927,000	611,892,000
Operating income (loss)	53,075,000	39,733,000	(12,583,000)
Other expense (income):
Interest income	(367,000)	(273,000)	(273,000)
Interest expense	25,102,000	26,294,000	25,160,000
Loss on debt extinguishment	0	7,352,000	517,000
Impairment of investments	0	1,069,000	0
Other income	(1,439,000)	(745,000)	(935,000)
Other expense, net	23,296,000	33,697,000	24,469,000
Income (loss) before income taxes	29,779,000	6,036,000	(37,052,000)
Benefit for income taxes	(1,874,000)	(384,000)	(15,253,000)
Net income (loss)	$ 31,653,000	$ 6,420,000	$ (21,799,000)
Basic earnings (loss) per common share:
Weighted average common shares outstanding	47,226	42,688	41,846
Basic earnings (loss) per common share (in dollars per share)	$ 0.67	$ 0.15	$ (0.52)
Diluted earnings (loss) per common share:
Weighted average common shares outstanding	47,966	44,168	41,846
Diluted earnings (loss) per common share (in dollars per share)	$ 0.66	$ 0.15	$ (0.52)

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 31,653	$ 6,420	$ (21,799)
Hedging activity:
Interest rate swap settlements	(498)	(361)	(410)
Interest rate swap amounts reclassified into interest expense	553	363	421
Unrealized (loss) gain resulting from changes in fair value of derivative instruments	(4,788)	(1,476)	267
Unrealized gain resulting from changes in fair value of marketable securities	0	0	59
Other comprehensive (loss) income	(4,733)	(1,474)	337
Tax effect related to items of other comprehensive (loss) income	0	0	85
Other comprehensive (loss) income, net of tax	(4,733)	(1,474)	252
Comprehensive income (loss)	$ 26,920	$ 4,946	$ (21,547)

CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests	Class A Common Stock	Class A Common Stock Common Stock	Class B Common Stock	Class B Common Stock Common Stock
Beginning balance at Dec. 31, 2016	$ (24,550)	$ 348,434	$ (373,308)	$ (68)	$ (24)		$ 406		$ 10
Beginning balance (in shares) at Dec. 31, 2016							40,572,000		988,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances of Class A common stock	1,779	1,772					$ 7
Issuances of Class A common stock (in shares)							726,000
Stock-based compensation	6,432	6,432
Other	24				24
Net income (loss)	(21,799)		(21,799)
Hedging activity	252			252	0
Ending balance at Dec. 31, 2017	(37,862)	356,638	(395,107)	184	0		$ 413		$ 10
Ending balance (in shares) at Dec. 31, 2017						41,298,000	41,298,000	988,000	988,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances of Class A common stock	1,017	1,012					$ 5
Issuances of Class A common stock (in shares)							496,000
Issuance of Class A common stock - acquisition	7,622	7,621					$ 1
Issuance of Class A common stock - acquisition (in shares)							150,000
Stock-based compensation	8,445	8,445
Net income (loss)	6,420		6,420
Hedging activity	(1,474)			(1,474)
Ending balance at Dec. 31, 2018	(15,832)	373,716	(388,669)	(1,308)	0		$ 419		$ 10
Ending balance (in shares) at Dec. 31, 2018						41,944,000	41,944,000	988,000	988,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A common stock - equity offering	100,446	100,410					$ 36
Issuance of Class A common stock - equity offering (in shares)							3,565,000
Issuances of Class A common stock	3,996	3,984					$ 12
Issuances of Class A common stock (in shares)							1,227,000
Issuance of Class A common stock - acquisition	0	(1)					$ 1
Issuance of Class A common stock - acquisition (in shares)							67,000
Stock-based compensation	7,223	7,223
Net income (loss)	31,653		31,653
Hedging activity	(4,733)			(4,733)
Ending balance at Dec. 31, 2019	$ 122,753	$ 485,332	$ (357,016)	$ (6,041)	$ 0		$ 468		$ 10
Ending balance (in shares) at Dec. 31, 2019						46,803,000	46,803,000	988,000	988,000

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash Flows from Operating Activities:
Net income (loss)	$ 31,653,000	$ 6,420,000	$ (21,799,000)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	79,790,000	70,508,000	62,102,000
Operating lease right-of-use assets expense	9,559,000
Depletion of landfill operating lease obligations		9,724,000	9,646,000
Interest accretion on landfill and environmental remediation liabilities	6,976,000	5,708,000	4,482,000
Amortization of debt issuance costs and discount on long-term debt	2,293,000	2,449,000	2,692,000
Stock-based compensation	7,223,000	8,445,000	6,432,000
(Gain) loss on sale of property and equipment	(892,000)	(492,000)	49,000
Southbridge Landfill non-cash closure charge, net	74,000	16,179,000	63,526,000
Southbridge Landfill insurance recovery for investing activities	0	(3,506,000)	0
Development project charge	0	311,000	0
Non-cash expense from acquisition activities and other items	65,000	757,000	0
Loss on debt extinguishment	0	7,352,000	517,000
Impairment of investments	0	1,069,000	0
Withdrawal costs - multiemployer pension plan	2,230,000	0	0
Deferred income taxes	(1,244,000)	1,250,000	(15,525,000)
Changes in assets and liabilities, net of effects of acquisitions and divestitures:
Accounts receivable	(5,464,000)	(5,833,000)	(4,664,000)
Landfill operating lease contract expenditures	(5,307,000)	0	0
Accounts payable	6,762,000	9,091,000	2,084,000
Prepaid expenses, inventories and other assets	(1,669,000)	535,000	(1,404,000)
Accrued expenses, contract liabilities and other liabilities	(22,931,000)	(9,133,000)	(600,000)
Net cash provided by operating activities	116,829,000	120,834,000	107,538,000
Cash Flows from Investing Activities:
Acquisitions, net of cash acquired	(75,379,000)	(88,918,000)	(5,056,000)
Additions to property, plant and equipment	(103,165,000)	(73,232,000)	(64,862,000)
Payments on landfill operating lease contracts	0	(7,415,000)	(7,240,000)
Proceeds from sale of property and equipment	750,000	870,000	711,000
Proceeds from property insurance settlement	332,000	992,000	0
Net cash used in investing activities	(177,462,000)	(164,197,000)	(76,447,000)
Cash Flows from Financing Activities:
Proceeds from debt borrowings	197,800,000	634,700,000	185,500,000
Principal payments on debt	(243,374,000)	(584,223,000)	(216,966,000)
Payments of debt issuance costs	(749,000)	(5,573,000)	(1,452,000)
Proceeds from the exercise of share based awards	3,355,000	471,000	1,278,000
Proceeds from the public offering of Class A Common Stock	100,446,000	0	0
Proceeds from unregistered sale of Class A Common Stock	2,619,000	0	0
Net cash provided by (used in) financing activities	60,097,000	45,375,000	(31,640,000)
Net (decrease) increase in cash and cash equivalents	(536,000)	2,012,000	(549,000)
Cash and cash equivalents, beginning of period	4,007,000	1,995,000	2,544,000
Cash and cash equivalents, end of period	3,471,000	4,007,000	1,995,000
Supplemental Disclosures of Cash Flow Information:
Interest	23,183,000	23,523,000	25,029,000
Income tax (refunds) payments, net	(1,631,000)	105,000	146,000
Supplemental Disclosures of Non-Cash Investing and Financing Activities:
Non-current assets acquired through long-term obligations	13,053,000	7,092,000	3,564,000
Landfills
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Operating lease right-of-use assets expense	7,711,000
Cash Flows from Investing Activities:
Proceeds from property insurance settlement	$ 0	$ 3,506,000	$ 0

BASIS OF PRESENTATION	12 Months Ended
BASIS OF PRESENTATION	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
BASIS OF PRESENTATION	BASIS OF PRESENTATION Casella Waste Systems, Inc. (“Parent”), its consolidated subsidiaries and any partially owned entities over which it has a controlling financial interest (collectively, “we”, “us” or “our”), is a regional, vertically integrated solid waste services company that provides collection, transfer, disposal, landfill, landfill gas-to-energy, recycling and organics services in the northeastern United States. We market recyclable metals, aluminum, plastics, paper and corrugated cardboard, which have been processed at our recycling facilities, as well as recyclables purchased from third-parties. We manage our solid waste operations on a geographic basis through two regional operating segments, our Eastern and Western regions, each of which provides a full range of solid waste services, and our larger-scale recycling and commodity brokerage operations through our Recycling segment. Organics services, ancillary operations, along with major account and industrial services are included in our Other segment. Effective January 1, 2020, we reorganized our operating segments as follows: we aligned our organics services and our major account and industrial services, with our Recycling segment to form the Resource Solutions segment, thus creating a single resource renewal-focused segment. We also moved our ancillary transportation services, which were previously included in our Other segment, into our Western region. Accordingly, as of January 1, 2020, our operating segments consist of the Eastern and Western regions and Resource Solutions. The accompanying consolidated financial statements, which include the accounts of the Parent, our wholly-owned subsidiaries and any partially owned entities over which we have a controlling financial interest, have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). All significant intercompany accounts and transactions are eliminated in consolidation. Investments in entities in which we do not have a controlling financial interest are accounted for under either the equity method or the cost method of accounting, as appropriate.

ACCOUNTING CHANGES

12 Months Ended

Dec. 31, 2019

Accounting Changes and Error Corrections [Abstract]

ACCOUNTING CHANGES

A table providing a brief description of recent Accounting Standards Updates ("ASUs") to the Accounting Standards Codification (“ASC”) issued by the Financial Accounting Standards Board (“FASB”) that we adopted and deemed to have a material impact on our consolidated financial statements based on current account balances and activity follows:

Standard

Description

Effect on the Financial Statements or Other
Significant Matters

Accounting standards adopted effective January 1, 2019

ASU No. 2016-02, as amended through March 2019: Leases (Topic 842)

Requires that a lessee recognize at the commencement date: a lease liability, which is the obligation of the lessee to make lease payments arising from a lease, measured on a discounted basis; and a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term.

We adopted the guidance using the prospective optional transition method effective January 1, 2019, which allowed us to elect not to restate comparative periods and, if applicable, to recognize the effects of applying this guidance as a cumulative-effect adjustment to retained earnings as of January 1, 2019. We did not recognize a cumulative effect adjustment to retained earnings upon implementation. Upon adopting this guidance, we recognized a right-of-use asset and lease liability for leases classified as operating leases with a term in excess of 12 months in our consolidated balance sheet. We also prospectively reclassified landfill operating lease payments, along with related accumulated depreciation, that were previously capitalized as property, plant and equipment to operating lease right-of-use assets. Accordingly, the related cash outlays, which were historically considered cash flows from investing activities, were prospectively reclassified as cash flows from operating activities in accordance with Topic 842. With the assistance of third-party resources, we designed internal controls over the adoption of this guidance and implemented a third-party enterprise lease management software solution. In conjunction with the implementation, we modified our lease policy and internal business processes to effectively manage and account for leases, and to support recognition and disclosure requirements under the new standard. The adoption of this guidance did not have a material impact on the accounting for our finance leases. This guidance required additional disclosure over leases in order to comply with the new lease standard. See Note 8, Leases for additional disclosure.

A table providing a brief description of recent ASUs to the ASC issued by the FASB that are pending adoption and deemed to have a possible material impact on our consolidated financial statements based on current account balances and activity follows:

Standard

Description

Effect on the Financial Statements or Other
Significant Matters

Accounting standards issued pending adoption

ASU No. 2019-12: Income Taxes (Topic 740)

Reduces the complexity over accounting for income taxes by removing certain exceptions and amending guidance to improve consistent application of accounting over income taxes.

We are currently assessing the provisions of this guidance to determine whether or not its adoption will have an impact on our consolidated financial statements and related disclosures. This guidance is effective January 1, 2021 with early adoption permitted.

ASU No. 2017-04: Intangibles - Goodwill and Other (Topic 350)

Requires that when an entity is performing its annual, or interim, goodwill impairment test, it should compare the fair value of the reporting unit with its carrying amount when calculating its impairment charge, noting that the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. Additionally, if applicable, an entity should consider income tax effects from any tax-deductible goodwill on the carrying amount of the reporting unit when calculating its impairment charge.

As of December 31, 2019, we did not record a goodwill impairment charge related to our annual goodwill impairment test because at that time the fair value of each reporting unit exceeded its respective carrying value. Upon adoption, if the carrying value of any of these reporting units exceeds the fair value when we perform a goodwill impairment test, we would record an impairment charge equal to the amount by which the carrying value exceeds its fair value. We adopted this guidance effective January 1, 2020 and we do not expect our adoption of this guidance to have a material impact on our consolidated financial statements.

ASU No. 2016-13: Financial Instrument Credit Losses (Topic 326)

Requires that an entity measures all of its expected credit losses for financial assets held based on historical experience, current conditions, and reasonable and supportable forecasts.

This guidance is effective for fiscal years beginning after December 15, 2019, including interim periods within that fiscal year. We adopted this guidance effective January 1, 2020 using the required modified-retrospective approach. We are currently assessing the provisions of this guidance, and we do not expect our adoption of this standard to have a material impact on our consolidated financial statements or to result in a material cumulative effect adjustment to retained earnings as of January 1, 2020.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

12 Months Ended

Dec. 31, 2019

Accounting Policies [Abstract]

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Management’s Estimates and Assumptions

Preparation of our consolidated financial statements in accordance with GAAP requires management to make certain estimates and assumptions. These estimates and assumptions affect the accounting for and recognition and disclosure of assets, liabilities, equity, revenues and expenses. We must make these estimates and assumptions because certain information that we use is dependent on future events, cannot be calculated with a high degree of precision given the available data or simply cannot be readily calculated. In some cases, these estimates are difficult to determine, and we must exercise significant judgment. In preparing our consolidated financial statements, the estimates and assumptions that we consider to be significant and that present the greatest amount of uncertainty relate to our accounting for landfills, environmental remediation liabilities, asset impairments, accounts receivable valuation allowance, self-insurance reserves, deferred taxes and uncertain tax positions, estimates of the fair values of assets acquired and liabilities assumed in any acquisition, contingent liabilities and stock-based compensation. Each of these items is discussed in more detail elsewhere in these notes to consolidated financial statements, as applicable. Actual results may differ materially from the estimates and assumptions that we use in the preparation of our consolidated financial statements.

Cash and Cash Equivalents

We consider all highly liquid investments purchased with original maturities of three months or less to be cash equivalents.

Concentrations of Credit Risk

Financial instruments that potentially subject us to concentrations of credit risk consist of cash and cash equivalents, restricted investment securities, accounts receivable and derivative instruments. We maintain cash and cash equivalents and restricted investment securities with banks that at times exceed applicable insurance limits. We reduce our exposure to credit risk by maintaining such deposits with high quality financial institutions. Our concentration of credit risk with respect to accounts receivable is limited because of the large number and diversity of customers we serve, thus reducing the credit risk associated with any one customer group. As of December 31, 2019, no single customer or customer group represented greater than 5% of total accounts receivable. We manage credit risk through credit evaluations, credit limits, and monitoring procedures, but generally do not require collateral to support accounts receivable. We reduce our exposure to credit risk associated with derivative instruments by entering into agreements with high quality financial institutions and by evaluating and regularly monitoring their creditworthiness.

Accounts Receivable, Net of Allowance for Doubtful Accounts

Accounts receivable represent receivables from customers for collection, transfer, recycling, disposal and other services. Our accounts receivable are recorded when billed or when related revenue is earned, if earlier, and represent claims against third-parties that will be settled in cash. The carrying value of our accounts receivable, net of allowance for doubtful accounts represents its estimated net realizable value. Estimates are used in determining our allowance for doubtful accounts based on our historical collection experience, current economic conditions and trends, credit policy and a review of our accounts receivable by aging category. Our reserve is evaluated and revised on a monthly basis. Past due accounts receivable are written off when deemed to be uncollectible.

Inventory

Inventory includes secondary fibers, recyclables ready for sale, and parts and supplies. Inventory is stated at the lower of cost (first-in, first-out) or market.

Property, Plant and Equipment

Property, plant and equipment is recorded at cost, less accumulated depreciation and amortization. We provide for depreciation and amortization using the straight-line method by charges to operations in amounts that allocate the cost of the assets over their estimated useful lives as follows:


Asset Classification						Estimated Useful Life
Buildings and improvements						10-30 years
Machinery and equipment						5-10 years
Rolling stock						5-10 years
Containers						5-12 years
Furniture and Fixtures						3-8 years

The cost of maintenance and repairs is charged to operations as incurred.

Landfill development costs are included in property, plant and equipment. Landfill development costs include costs to develop each of our landfill sites, including such costs related to landfill liner material and installation, excavation for airspace, landfill leachate collection systems, landfill gas collection systems, environmental monitoring equipment for groundwater and landfill gas, directly related engineering, capitalized interest, on-site road construction, and other capital infrastructure. Additionally, landfill development costs include all land purchases within the landfill footprint and the purchase of any required landfill buffer property. Under life-cycle accounting, these costs are capitalized and charged to expense based on tonnage placed into each site.

See the “Landfill Accounting” accounting policy below for additional disclosure over the amortization of landfill development costs and Note 7, Property, Plant and Equipment for disclosure over property, plant and equipment.

Landfill Accounting

Life Cycle Accounting

Under life-cycle accounting, all costs related to acquisition and construction of landfill sites are capitalized and charged to expense based on tonnage placed into each site. Landfill permitting, acquisition and preparation costs are amortized on the units-of-consumption method as landfill airspace is consumed. In determining the amortization rate for each of our landfills, preparation costs include the total estimated costs to complete construction of the landfills’ permitted and expansion capacity.

Landfill Development Costs

We estimate the total cost to develop each of our landfill sites to its remaining permitted and expansion capacity (see landfill development costs discussed within the “Property, Plant and Equipment” accounting policy above). The projection of these landfill costs is dependent, in part, on future events. The remaining amortizable basis of each landfill includes costs to develop a site to its remaining permitted and expansion capacity and includes amounts previously expended and capitalized, net of accumulated airspace amortization, and projections of future purchase and development costs including capitalized interest. The interest capitalization rate is based on our weighted average interest rate incurred on borrowings outstanding during the period. Interest capitalized during the fiscal years ended December 31, 2019 ("fiscal year 2019"), December 31, 2018 ("fiscal year 2018") and December 31, 2017 ("fiscal year 2017") was $263, $140 and $295, respectively.

Landfill Airspace

We apply the following guidelines in determining a landfill’s remaining permitted and expansion airspace:

Remaining Permitted Airspace. Our engineers, in consultation with third-party engineering consultants and surveyors, are responsible for determining remaining permitted airspace at our landfills. The remaining permitted airspace is determined by an annual survey, which is then used to compare the existing landfill topography to the expected final landfill topography.

Expansion Airspace. We currently include unpermitted expansion airspace in our estimate of remaining permitted and expansion airspace in certain circumstances. To be considered expansion airspace all of the following criteria must be met:

•we control the land on which the expansion is sought;

•all technical siting criteria have been met or a variance has been obtained or is reasonably expected to be obtained;

•we have not identified any legal or political impediments which we believe will not be resolved in our favor;

•we are actively working on obtaining any necessary permits and we expect that all required permits will be received; and

•senior management has approved the project based on a review of the engineering design and determination that the financial return profile meets our investment criteria.

For unpermitted airspace to be included in our estimate of remaining permitted and expansion airspace, the expansion effort must meet all of the criteria listed above. These criteria are evaluated annually by our engineers, accountants, lawyers, managers and others to identify potential obstacles to obtaining the permits. Once the remaining permitted and expansion airspace is determined in cubic yards, an airspace utilization factor (“AUF”) is established to calculate the remaining permitted and expansion capacity in tons. The AUF is established using a process that considers the measured density obtained from annual surveys. When we include the expansion airspace in our calculation of remaining permitted and expansion airspace, we include the projected costs for development, as well as the projected asset retirement costs related to final capping, closure and post-closure of the expansion airspace in the amortization basis of the landfill.

After determining the costs and the remaining permitted and expansion capacity at each of our landfills, we determine the per ton rates that will be expensed as waste is received and deposited at each of our landfills by dividing the costs by the corresponding number of tons. We calculate per ton amortization rates for assets associated with each final capping event, for assets related to closure and post-closure activities, and for all other costs capitalized or to be capitalized in the future for each landfill. These rates per ton are updated annually, or more frequently, as significant facts change.

It is possible that actual results, including the amount of costs incurred, the timing of final capping, closure and post-closure activities, our airspace utilization or the success of our expansion efforts, could ultimately turn out to be significantly different from our estimates and assumptions. To the extent that such estimates or related assumptions prove to be significantly different than actual results, lower profitability may be experienced due to higher amortization rates, higher final capping, closure or post-closure rates, or higher expenses. Higher profitability may result if the opposite occurs. Most significantly, if it is determined that the expansion capacity should no longer be considered in calculating the recoverability of the landfill asset, we may be required to recognize an asset impairment. If it is determined that the likelihood of receiving an expansion permit has become remote, the capitalized costs related to the expansion effort are expensed immediately.

Final Capping, Closure and Post-Closure Costs

The following is a description of our landfill asset retirement activities and related accounting:

Final Capping Costs. Final capping activities include the installation of liners, drainage, compacted soil layers and topsoil over areas of a landfill where total airspace has been consumed and waste is no longer being received. Final capping activities occur throughout the life of the landfill. Our engineering personnel estimate the cost for each final capping event based on the acreage to be capped, along with the final capping materials and activities required. The estimates also consider when these costs would actually be paid and factor in inflation and discount rates. The engineers then quantify the landfill capacity associated with each final capping event and the costs for each event are amortized over that capacity as waste is received at the landfill.

Closure and Post-Closure Costs. Closure and post-closure costs represent future estimated costs related to monitoring and maintenance of a solid waste landfill after a landfill facility ceases to accept waste and closes. We estimate, based on input from our engineers, accountants, lawyers, managers and others, our future cost requirements for closure and post-closure monitoring and maintenance based on our interpretation of the technical standards of the Subtitle D regulations and the air emissions standards under the Clean Air Act of 1970, as amended, as they are being applied on a state-by-state basis. Closure and post-closure accruals for the cost of monitoring and maintenance include site inspection, groundwater monitoring, leachate management, methane gas control and recovery, and operation and maintenance costs to be incurred for a period which is generally for a term of 30 years after final closure of a landfill. In determining estimated future closure and post-closure costs, we consider costs associated with permitted and permittable airspace.

Our estimated future final capping, closure and post-closure costs, based on our interpretation of current requirements and proposed regulatory changes, are intended to approximate fair value. Absent quoted market prices, our cost estimates are based on historical experience, professional engineering judgment and quoted or actual prices paid for similar work. Our estimate of costs to discharge final capping, closure and post-closure asset retirement obligations for landfills are developed in today’s dollars. These costs are then inflated to the period of performance using an estimate of inflation, which is updated annually (1.6% as of December 31, 2019). Final capping, closure and post-closure liabilities are discounted using the credit adjusted risk-free rate in effect at the time the obligation is incurred. The weighted average rate applicable to our asset retirement obligations as of December 31, 2019 is between approximately 8.7% and 10.0%, the range of the credit adjusted risk free rates effective since the adoption of guidance associated with asset retirement obligations in the fiscal year ended April 30, 2004. Accretion expense is necessary to increase the accrued final capping, closure and post-closure liabilities to the future anticipated obligation. To accomplish this, we accrete our final capping, closure and post-closure accrual balances using the same credit-adjusted risk-free rate that was used to calculate the recorded liability. Accretion expense on recorded landfill liabilities is recorded to cost of operations from the time the liability is recognized until the costs are paid. Accretion expense on recorded landfill liabilities amounted to $6,227, $5,556 and $4,401 in fiscal years 2019, 2018 and 2017, respectively.

We provide for the accrual and amortization of estimated future obligations for closure and post-closure based on tonnage placed into each site. With regards to final capping, the liability is recognized, and the costs are amortized based on the airspace related to the specific final capping event.

See Note 10, Final Capping, Closure and Post-Closure Costs for disclosure over asset retirement obligations related to final capping, closure and post-closure costs.

We operate in states which require a certain portion of landfill final capping, closure and post-closure obligations to be secured by financial assurance, which may take the form of surety bonds, letters of credit and restricted investment securities. Surety bonds securing closure and post-closure obligations at December 31, 2019 and December 31, 2018 totaled $220,633 and $201,177, respectively. Letters of credit securing closure and post-closure obligations as of December 31, 2019 and December 31, 2018 totaled $0 and $0, respectively. See Note 6, Restricted Assets for disclosure over restricted investment securities securing closure and post-closure obligations.

Lease Accounting

We lease vehicles, equipment, property and other non-core equipment in the ordinary course of our business. Leases are classified as either operating leases or finance leases, as appropriate. Our leases have varying terms and may include renewal or purchase options, escalation clauses, restrictions, lease concessions, capital project funding, penalties or other obligations that we considered historically in determining minimum rental payments. We recognize lease expense for operating leases on a straight-line basis over the lease term. We recognize depreciation expense for finance leases over either the useful life of the asset or the lease term based on the terms of the lease agreement.

We are also party to three landfill operation and management agreements. These agreements are long-term landfill operating contracts with government bodies whereby we receive tipping revenue, pay normal operating expenses and assume future final capping, closure and post-closure obligations. The government body retains ownership of the landfill. There is no bargain purchase option and title to the property does not pass to us at the end of the lease term. We allocate the consideration paid to the landfill airspace rights and underlying land lease based on the relative fair values.

In addition to up-front or one-time payments, the landfill operating agreements may require us to make future minimum rental payments, including success/expansion fees, other direct costs and final capping, closure and post-closure costs. The value of all future minimum rental payments is amortized and charged to cost of operations over the life of the contract. We amortize the consideration allocated to airspace rights as airspace is utilized on a units-of-consumption basis and such amortization is charged to cost of operations as airspace is consumed (e.g., as tons are placed into the landfill). The underlying value of any land lease is amortized to cost of operations on a straight-line basis over the estimated life of the operating agreement.

As a part of the implementation of Topic 842, we elected to adopt the practical expedient package and to not elect the hindsight practical expedient in determining lease term. The practical expedient package allowed us to: 1) not reassess lease classification for existing leases; 2) not reassess whether a contract contains a lease for existing contracts; and 3) not reassess initial direct costs for existing leases. Accordingly, we retained the operating lease and finance lease classifications in all periods presented and did not alter Topic 840 accounting over operating leases in place at transition allowing us to use historical minimum rental payments when determining the right-of-use asset and lease liability for existing operating leases. Upon adopting this guidance, we recognized a right-of-use asset and a lease liability for core leases classified as operating leases with a term in excess of 12 months in our consolidated balance sheet. For other non-core operating leases, which is comprised of small-dollar-value items such as office equipment, we continued to expense these costs in the period incurred rather than capitalizing such expenditures on our consolidated balance sheet. Accounting for finance leases was not impacted by the adoption of this guidance.

Under Topic 842, we identify lease and nonlease components in a contract to which consideration in the contract will be allocated. We may elect by class of underlying asset to choose not to separate nonlease components from lease components and instead account for each separate lease component and the nonlease components in a contract as part of the single lease component. We have elected to not separate lease components from nonlease components for property leases and are, therefore, not allocating consideration between lease and nonlease components for this asset class. Lease payments include: fixed payments, including in-substance fixed payments, less any lease incentives paid or payable to the lessee; variable lease payments that depend on an index or a rate; exercise price of a purchase option reasonably certain to be exercised; penalties for terminating a lease; and amounts where it is probable that we will owe under a residual value guarantee. Refundable deposits are not considered to be a fixed payment. Variable lease costs that are not based on an index or a rate are recorded to expense in the period incurred. Lease term is determined at lease commencement, and includes any noncancellable period for which we have the right to use the underlying asset together with any periods covered by an option to extend or terminate the lease if we are reasonably certain to exercise the option to extend or not to exercise the option to terminate. The initial determination of a lease liability is calculated as the net present value of the lease payments not yet paid. The discount rate used to determine present value is the rate implicit in the lease, if present, or, if not present, our incremental borrowing rate, which is a rate that reflects interest that we would have to pay to borrow funds on a collateralized basis over a similar term to the lease and in a similar economic environment. For shorter term leases, such as vehicle and equipment leases, we calculate our incremental borrowing rate using the interest rate from our existing secured line of credit, adjusted based on term. For longer term leases, such as our landfill operating leases, we calculate our incremental borrowing rate based on an industry yield curve with a similar credit rating, adjusted by a company specific spread as determined by a third-party.

See Note 8, Leases for further disclosure over lease costs and other lease information.

Goodwill and Intangible Assets

Goodwill. Goodwill is the excess of our purchase cost over the fair value of the net assets of acquired businesses. We do not amortize goodwill, but as discussed in the “Asset Impairments” accounting policy below, we assess our goodwill for impairment at least annually.

See Note 9, Goodwill and Intangible Assets for disclosure over goodwill.

Intangible Assets. Intangible assets consist primarily of covenants not-to-compete and customer lists. Intangible assets are recorded at fair value and are amortized based on the economic benefit provided or using the straight-line method over their estimated useful lives. Covenants not-to-compete and customer lists are typically amortized over a term of no more than 10 years.

See Note 9, Goodwill and Intangible Assets for disclosure over intangible assets.

Investments in Unconsolidated Entities

Investments in unconsolidated entities over which we have significant influence over the investees’ operating and financing activities are accounted for under the equity method of accounting. Investments in affiliates in which we do not have the ability to exert significant influence over the investees’ operating and financing activities are accounted for under the cost method of accounting. As of December 31, 2019 and December 31, 2018, we had no investments accounted for under the equity method of accounting. As of both December 31, 2019 and December 31, 2018, we had cost method investments totaling $11,264.

We monitor and assess the carrying value of our investments throughout the year for potential impairment and write them down to their fair value when other-than-temporary declines exist. Fair value is generally based on (i) other third-party investors’ recent transactions in the securities; (ii) other information available regarding the current market for similar assets and/or (iii) a market or income approach, as deemed appropriate.

When we assess the carrying value of our investments for potential impairment, determining the fair value of our investments is reliant upon the availability of market information and/or other information provided by third-parties to be able to develop an estimate of fair value. Considerable judgment is required in interpreting market data to develop the estimates of fair value. Accordingly, our estimates are not necessarily indicative of the amounts that we, or other holders of these investments, could realize in a current market exchange. The use of different assumptions and/or estimation methodologies could have a significant effect on the estimated fair values. The estimates of fair value could differ significantly from the amounts presented. See “Asset Impairments” accounting policy below.

Fair Value of Financial Instruments

Our financial instruments may include cash and cash equivalents, accounts receivable, restricted investment securities held in trust on deposit with various banks as collateral for our obligations relative to our landfill final capping, closure and post-closure costs, restricted cash reserved to finance certain capital projects, interest rate derivatives, trade payables and long-term debt. Accounting standards include disclosure requirements around fair values used for certain financial instruments and establish a fair value hierarchy. The three-tier hierarchy prioritizes valuation inputs into three levels based on the extent to which inputs used in measuring fair value are observable in the market. Each fair value measurement is reported in one of three levels: Level 1, defined as quoted market prices in active markets for identical assets or liabilities; Level 2, defined as inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; and Level 3, defined as unobservable inputs that are not corroborated by market data.

See Note 11, Debt and Note 14, Fair Value of Financial Instruments for fair value disclosure over long-term debt and financial instruments, respectively. See the “Derivatives and Hedging” accounting policy below for the fair value disclosure over interest rate derivatives.

Business Combinations

We acquire businesses in the waste industry, including non-hazardous waste collection, transfer station, recycling and disposal operations, as part of our growth strategy. Businesses are included in the consolidated financial statements from the date of acquisition.

We recognize, separately from goodwill, the identifiable assets acquired and liabilities assumed at their estimated acquisition-date fair values. We measure and recognize goodwill as of the acquisition date as the excess of: (a) the aggregate of the fair value of consideration transferred, the fair value of any noncontrolling interest in the acquiree (if any) and the acquisition date fair value of our previously held equity interest in the acquiree (if any), over (b) the fair value of net assets acquired and liabilities assumed. If information about facts and circumstances existing as of the acquisition date is incomplete by the end of the reporting period in which a business combination occurs, we will report provisional amounts for the items for which the accounting is incomplete. The measurement period ends once we receive the information we were seeking; however, this period will not extend beyond one year from the acquisition date. Any material adjustments recognized during the measurement period will be recognized retrospectively in the consolidated financial statements of the current period. All acquisition related transaction and restructuring costs are to be expensed as incurred.

See Note 5, Business Combinations for disclosure over business acquisitions.

Environmental Remediation Liabilities

We have recorded environmental remediation liabilities representing our estimate of the most likely outcome of the matters for which we have determined that a liability is probable. These liabilities include potentially responsible party investigations, settlements, certain legal and consultant fees, as well as costs directly associated with site investigation and clean up, such as materials and incremental internal costs directly related to the remedy. We provide for expenses associated with environmental remediation obligations when such amounts are probable and can be reasonably estimated. We estimate costs required to remediate sites where it is probable that a liability has been incurred based on site-specific facts and circumstances. Estimates of the cost for the likely remedy are developed using third-party environmental engineers or other service providers. Where we believe that both the amount of a particular environmental remediation liability and timing of payments are reliably determinable, we inflate the cost in current dollars until the expected time of payment and discount the cost to present value.

See Note 12, Commitments and Contingencies for disclosure over environmental remediation liabilities.

Self-Insurance Liabilities and Related Costs

We are self-insured for vehicles and workers’ compensation with reinsurance coverage limiting our maximum exposure. Our maximum exposure in fiscal year 2019 under the workers’ compensation plan was $1,250 per individual event. Our maximum exposure in fiscal year 2019 under the automobile plan was $1,200 per individual event. The liability for unpaid claims and associated expenses, including incurred but not reported losses, is determined by management with the assistance of a third-party actuary and reflected in our consolidated balance sheet as an accrued liability. We use a third-party to track and evaluate actual claims experience for consistency with the data used in the annual actuarial valuation. The actuarial-determined liability is calculated based on historical data, which considers both the frequency and settlement amount of claims. Our self-insurance reserves totaled $16,853 and $15,040 as of December 31, 2019 and December 31, 2018, respectively. Our estimated accruals for these liabilities could be significantly different than our ultimate obligations if variables such as the frequency or severity of future events differ significantly from our assumptions.

Income Taxes

We use estimates to determine our provision for income taxes and related assets and liabilities and any valuation allowance recorded against our net deferred tax assets. Valuation allowances have been established for the possibility that tax benefits may not be realized for certain deferred tax assets. Deferred income taxes are recognized based on the expected future tax consequences of differences between the financial statement basis and the tax basis of assets and liabilities, calculated using currently enacted tax rates. We record net deferred tax assets to the extent we believe these assets will more likely than not be realized. In making this determination, we consider all available positive and negative evidence, including scheduled reversals of deferred tax liabilities, projected future taxable income, tax planning strategies and recent financial operations. In the event we determine that we would be able to realize our deferred income tax assets in the future in excess of their net recorded amount, we will make an adjustment to the valuation allowance which would reduce the provision for income taxes.

We account for income tax uncertainties according to guidance on the recognition, de-recognition and measurement of potential tax benefits associated with tax positions. We recognize interest and penalties relating to income tax matters as a component of income tax expense.

See Note 16, Income Taxes for disclosure related to income taxes, including the effect of the Act on income taxes.

Derivatives and Hedging

We account for derivatives and hedging activities in accordance with derivatives and hedging accounting guidance that establishes accounting and reporting standards requiring that every derivative instrument (including certain derivative instruments embedded in other contracts) be recorded in the balance sheet as either an asset or liability measured at its fair value. The guidance requires that changes in the derivative’s fair value be recognized currently in earnings unless specific hedge accounting criteria are met.

Our objective for utilizing derivative instruments is to reduce our exposure to fluctuations in cash flows due to changes in the commodity prices of recycled paper and adverse movements in interest rates.

Our strategy to hedge against fluctuations in the commodity prices of recycled paper is to enter into hedges to mitigate the variability in cash flows generated from the sales of recycled paper at floating prices, resulting in a fixed price being received from these sales. We evaluate the hedges and ensure that these instruments qualify for hedge accounting pursuant to derivative and hedging guidance. Designated as highly effective cash flow hedges, both the effective and ineffective portion of the change in the fair value of these derivatives is recorded in our stockholders’ equity (deficit) as a component of accumulated other comprehensive loss until the hedged item is settled and recognized as part of commodity revenue. If the price per short ton of the underlying commodity, as reported on the Official Board Market, is less than the contract price per short ton, we receive the difference between the average price and the contract price (multiplied by the notional tons) from the respective counter-party. If the price per short ton of the underlying commodity exceeds the contract price per short ton, we pay the calculated difference to the counter-party. The fair value of commodity hedges is obtained or derived from our counter-parties using valuation models that take into consideration market price assumptions for commodities based on underlying active markets. We were not party to any commodity hedge contracts as of December 31, 2019.

Our strategy to hedge against fluctuations in variable interest rates involves entering into interest rate derivative agreements to hedge against adverse movements in interest rates. For interest rate derivatives deemed to be highly effective cash flow hedges, both the effective and ineffective portion of the change in fair value of these derivatives is recorded in our stockholders’ equity (deficit) as a component of accumulated other comprehensive loss and reclassified into earnings through interest expense in the same period or periods during which the hedged transaction affects earnings.

See Note 14, Fair Value of Financial Instruments for fair value disclosure over derivative instruments and Note 11, Debt for further disclosure over interest rate derivatives.

Contingent Liabilities

We are subject to various legal proceedings, claims and regulatory matters, the outcomes of which are subject to significant uncertainty. We determine whether to disclose or accrue for loss contingencies based on an assessment of whether the risk of loss is remote, reasonably possible or probable, and whether it can be reasonably estimated. We analyze our litigation and regulatory matters based on available information to assess the potential liabilities. Management’s assessment is developed based on an analysis of possible outcomes under various strategies. We accrue for loss contingencies when such amounts are probable and reasonably estimable. If a contingent liability is only reasonably possible, we will disclose the potential range of the loss, if estimable. We record losses related to contingencies in cost of operations or general and administration expenses, depending on the nature of the underlying transaction leading to the loss contingency.

See Note 12, Commitments and Contingencies for disclosure over loss contingencies, as applicable. Contingent liabilities accounted for under purchase accounting are recorded at their fair values. These fair values may be different from the values we would have otherwise recorded, had the contingent liability not been assumed as part of an acquisition of a business.

Revenue Recognition

We adopted ASU 2014-09, as amended, Revenue from Contracts with Customers (Topic 606) effective January 1, 2018. We adopted this guidance using the modified retrospective approach, noting that no cumulative effect adjustment to the beginning balance of Accumulated Deficit was needed. The comparative periods have not been restated and continue to be reported under Revenue Recognition (Topic 605). We applied this guidance to contracts that were not substantially completed contracts at the date of adoption. Additionally, contract modifications that occurred before the adoption date were not separately evaluated, rather the guidance was applied to the current version of the contract only. We disaggregate our revenues by applicable service line: collection, landfill, transfer, customer solutions, recycling, organics, transportation and landfill gas-to-energy.

Under the new revenue recognition guidance, revenues are measured based on the consideration specified in a contract with a customer. The circumstances that impact the timing and amount of revenue recognized for each applicable service line may vary based on the nature of the service performed. We generally recognize revenues for services over time as we satisfy the performance obligation by transferring control over the service to the customer as the service is performed and the benefit is received and consumed by the customer. Services are typically delivered in a series as a single bundled performance obligation over either a designated period of time or for specified number of services. Services may also be delivered as a single bundled service, on a period-to-period basis, or in a spot transaction. Consideration may be variable on a per ton basis and/or fixed. Fixed consideration is allocated to each distinct service and variable consideration is allocated to the increment of time that the service is performed, and we have the contractual right to the fee. Fees are typically billed weekly, monthly, quarterly or in advance. Generally, the amount of consideration that we have the right to receive that is invoiced to the customer directly corresponds to the value of our performance completed to date. We elected the optional exemption, to not disclose the amount of variable consideration included in the transaction price that is allocated to outstanding performance obligations when the variable consideration is allocated entirely to unsatisfied performance obligations or to a wholly unsatisfied promise to transfer a distinct good or service that forms part of a single performance obligation. Revenues that are not satisfied over time are recognized at a point-in-time. This typically includes the sale of recycled or organic materials, as well as renewable energy credits ("RECs"). Revenues from the sale of organic or recycled materials are recognized at a point-in-time as control of the materials transfers to the customer upon shipment or pick-up by the customer. Revenues from the sale of RECs are recognized at a point-in-time as the trade is executed and control transfers to the customer.

Payments to customers that are not in exchange for a distinct good or service are recorded as a reduction of revenues. Rebates to certain customers associated with payments for recycled or organic materials that are received and subsequently processed and sold to other third-parties amounted to $4,428 and $6,279 in fiscal year 2019 and 2018, respectively. Rebates are generally recorded as a reduction of revenues upon the sale of such materials, or upon receipt of the recycled materials at our facilities. These payments were previously recorded as a cost of operations. We did not record any revenues in fiscal year 2019 or fiscal year 2018 from performance obligations satisfied in previous periods.

Contract receivables, which are included in Accounts receivable, net are recorded when billed or when related revenue is earned, if earlier, and represent claims against third-parties that will be settled in cash. Accounts receivable, net includes gross receivables from contracts of $80,191 and $73,500 as of December 31, 2019 and December 31, 2018, respectively. Certain customers are billed in advance and, accordingly, recognition of the related revenues is deferred as a contract liability until the services are provided and control transferred to the customer. Contract liabilities of $2,299 and $3,074 as of December 31, 2019 and December 31, 2018, respectively, are presented separately on the face of the Consolidated Balance Sheets. Due to the short-term nature of advanced billings, substantially all of the deferred revenue recognized as a contract liability as of December 31, 2018 and December 31, 2017 was recognized as revenue during fiscal year 2019 and 2018 when the services were performed.

See Note 4, Revenue Recognition for disclosure over the new guidance.

Asset Impairments

Recovery of Long-Lived Assets. We continually assess whether events or changes in circumstances have occurred that may warrant revision of the estimated useful lives of our long-lived assets (other than goodwill) or whether the remaining balances of those assets should be evaluated for possible impairment. Long-lived assets include, for example, capitalized landfill costs, other property, plant and equipment, identifiable intangible assets, and operating lease right-of-use assets. Events or changes in circumstances that may indicate that an asset may be impaired include the following:

•a significant decrease in the market price of an asset or asset group;

•a significant adverse change in the extent or manner in which an asset or asset group is being used or in its physical condition;

•a significant adverse change in legal factors or in the business climate that could affect the value of an asset or asset group, including an adverse action or assessment by a regulator;

•an accumulation of costs significantly in excess of the amount originally expected for the acquisition or construction of a long-lived asset;

•a current period operating or cash flow loss combined with a history of operating or cash flow losses or a projection or forecast that demonstrates continuing losses associated with the use of a long-lived asset or asset group;

•a current expectation that, more likely than not, a long-lived asset or asset group will be sold or otherwise disposed of significantly before the end of its previously estimated useful life; or

•an impairment of goodwill at a reporting unit.

There are certain indicators listed above that require significant judgment and understanding of the waste industry when applied to landfill development or expansion. For example, a regulator may initially deny a landfill expansion permit application although the expansion permit is ultimately granted. In addition, management may periodically divert waste from one landfill to another to conserve remaining permitted landfill airspace. Therefore, certain events could occur in the ordinary course of business and not necessarily be considered indicators of impairment due to the unique nature of the waste industry.

If an impairment indicator occurs, we perform a test of recoverability by comparing the carrying value of the asset or asset group to its undiscounted expected future cash flows. We group our long-lived assets for this purpose at the lowest level for which identifiable cash flows are primarily independent of the cash flows of other assets or asset groups. If the carrying values are in excess of undiscounted expected future cash flows, we measure any impairment by comparing the fair value of the asset or asset group to its carrying value.

To determine fair value, we use discounted cash flow analyses and estimates about the future cash flows of the asset or asset group. This analysis includes a determination of an appropriate discount rate, the amount and timing of expected future cash flows and growth rates. The cash flows employed in our discounted cash flow analyses are typically based on financial forecasts developed internally by management. The discount rate used is commensurate with the risks involved. We may also rely on third-party valuations and or information available regarding the market value for similar assets.

If the fair value of an asset or asset group is determined to be less than the carrying amount of the asset or asset group, impairment in the amount of the difference is recorded in the period that the impairment occurs. Estimating future cash flows requires significant judgment and projections may vary from the cash flows eventually realized.

See Note 17, Other Items and Charges for disclosure related to long-lived asset impairments recognized during the reporting periods.

Goodwill. We annually assess goodwill for impairment at the end of our fiscal year or more frequently if events or circumstances indicate that impairment may exist.

We may assess whether a goodwill impairment exists using either a qualitative or a quantitative assessment. If we perform a qualitative assessment, it involves determining whether events or circumstances exist that indicate it is more likely than not that the fair value of a reporting unit is less than its carrying amount, including goodwill. If based on this qualitative assessment we determine it is not more likely than not that the fair value of a reporting unit is less than its carrying amount, we will not perform a quantitative assessment. If the qualitative assessment indicates that it is more likely than not that the fair value of a reporting unit is less than its carrying amount, or if we elect not to perform a qualitative assessment, we perform a quantitative assessment, or two-step impairment test, to determine whether goodwill impairment exists at the reporting unit.

In the first step (defined as “Step 1”) of testing for goodwill impairment, we estimate the fair value of each reporting unit, which we have determined to be our geographic operating segments, our Recycling segment and our Customer Solutions business, which is included in the Other segment, and compare the fair value with the carrying value of the net assets of each reporting unit. If the fair value is less than its carrying value, then we would perform a second step (defined as “Step 2”) and determine the fair value of the goodwill. In Step 2, the fair value of goodwill is determined by deducting the fair value of a reporting unit’s identifiable assets and liabilities from the fair value of the reporting unit as a whole, as if that reporting unit had just been acquired and the purchase price were being initially allocated.

To determine the fair value of each of our reporting units as a whole we use discounted cash flow analyses, which require significant assumptions and estimates about the future operations of each reporting unit. Significant judgments inherent in this analysis include the determination of appropriate discount rates, the amount and timing of expected future cash flows and growth rates. The cash flows employed in our discounted cash flow analyses are based on financial forecasts developed internally by management. Our discount rate assumptions are based on an assessment of our risk adjusted discount rate, applicable for each reporting unit. In assessing the reasonableness of our determined fair values of our reporting units, we evaluate our results against our current market capitalization.

If the fair value of goodwill is less than its carrying value for a reporting unit, an impairment charge would be recorded to earnings. The loss recognized cannot exceed the carrying amount of goodwill. After a goodwill impairment loss is recognized, the adjusted carrying amount of goodwill becomes its new accounting basis.

In addition to an annual goodwill impairment assessment, we would evaluate a reporting unit for impairment if events or circumstances change between annual tests indicating a possible impairment. Examples of such events or circumstances include the following:

•a significant adverse change in legal status or in the business climate;

•an adverse action or assessment by a regulator;

•a more likely than not expectation that a segment or a significant portion thereof will be sold; or

•the testing for recoverability of a significant asset group within the segment.

We elected to perform a quantitative analysis as part of our annual goodwill impairment test for fiscal year 2019. As of December 31, 2019, the Step 1 testing for goodwill impairment performed for our Eastern, Western, Recycling and Customer Solutions reporting units indicated that the fair value of each reporting unit exceeded its carrying amount, including goodwill. Furthermore, the Step 1 test indicated that in each case the fair value of our Eastern, Western, Recycling and Customer Solutions reporting units exceeded its carrying value by in excess of 34.4%. We incurred no impairment of goodwill as a result of our annual goodwill impairment tests in each of fiscal years 2019, 2018 and 2017. However, there can be no assurance that goodwill will not be impaired at any time in the future.

Effective January 1, 2020, we adopted ASU 2017-04, Intangibles - Goodwill and Other (Topic 350). Under this guidance Step 2 of the testing for goodwill impairment was eliminated and that going forward we would recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit's fair value, noting that the amount is not to exceed the total amount of goodwill allocated to that reporting unit. See Note 2, Accounting Changes for disclosure related to the adoption of this guidance.

Cost Method Investments. We monitor and assess the carrying value of our cost method investments throughout the year for potential impairment and write them down to their fair value when other-than-temporary declines exist. We incurred no impairment of cost method investments in fiscal year 2019 or fiscal year 2017.

As of December 31, 2018, we owned 6.8% of the outstanding common stock of Recycle Rewards, Inc. (“Recycle Rewards”), a company that markets an incentive-based recycling service. In fiscal year 2018, it was determined based on the operating performance of Recycle Rewards that our cost method investment in Recycle Rewards was potentially impaired. As a result, we performed a valuation analysis in fiscal year 2018, which used an income approach based on discounted cash flows to determine an equity value for Recycle Rewards in order to properly value our cost method investment in Recycle Rewards. Based on this analysis, it was determined that the fair value of our cost method investment in Recycle Rewards was less than the carrying amount and, therefore, we recorded an other-than-temporary investment impairment charge for the full cost method investment amount of $1,069 in fiscal year 2018. In October 2019, Recycle Rewards sold all or substantially all of its assets comprising the business to RTS RecycleBank, LLC, a subsidiary of Recycle Track Systems, pursuant to an asset purchase agreement. Based on our junior ownership position, we did not receive any proceeds from this disposition.

There can be no assurance that our cost method investments will not be impaired at any time in the future.

Defined Benefit Pension Plan

We make contributions to one qualified multiemployer defined benefit pension plan, the New England Teamsters and Trucking Industry Pension Fund ("Pension Plan"). The Pension Plan provides retirement benefits to participants based on their service to contributing employers. We do not administer this plan. The Pension Plan’s benefit formula is based on credited years of service and hours worked as defined in the Pension Plan document. Our pension contributions are made in accordance with funding standards established by the Employee Retirement Income Security Act of 1974 and the Internal Revenue Code, as amended by the Pension Protection Act of 2006. The Pension Plan’s assets have been invested as determined by the Pension Plan's fiduciaries in accordance with the Pension Plan's investment policy. The Pension Plan’s asset allocation is based on the Pension Plan's investment policy and is reviewed as deemed necessary.

See Note 15, Employee Benefit Plans for disclosure over the Pension Plan.

Stock-Based Compensation

All share-based compensation cost is measured at the grant date based on the estimated fair value of the award and is recognized as expense-in general and administration expense over the employee’s requisite service period. For purposes of calculating stock-based compensation expense, forfeitures are accounted for as they occur. Our equity awards granted generally consist of stock options, including market-based performance stock options, restricted stock, restricted stock units and performance stock units, including market-based performance stock units.

The fair value of each stock option grant is estimated using a Black-Scholes option-pricing model, with the exception of market-based performance stock option grants which are valued using a Monte Carlo option-pricing model. The fair value of restricted stock, restricted stock unit and performance stock unit grants is at a price equal to the fair market value of our Class A common stock at the date of grant. The fair value of market-based performance stock unit grants is valued using a Monte Carlo pricing model.

See Note 13, Stockholders' Equity for disclosure over stock-based compensation.

Earnings per Share

Basic earnings per share is computed by dividing the net income (loss) by the weighted average number of common shares outstanding during the period. Diluted earnings per share is calculated based on the combined weighted average number of common shares and potentially dilutive shares. Dilutive shares include the assumed exercise of employee stock options, including market-based performance stock options based on the expected achievement of performance targets, unvested restricted stock awards, unvested restricted stock units and unvested performance stock units, including market-based performance units based on the expected achievement of performance targets. In computing diluted earnings per share, we utilize the treasury stock method.

See Note 18, Earnings Per Share for disclosure over the calculation of earnings per share.

Subsequent Events

Except as disclosed, no material subsequent events have occurred since December 31, 2019 through the date of this filing that would require recognition or disclosure in our consolidated financial statements.

REVENUE RECOGNITION

12 Months Ended

Dec. 31, 2019

Revenue from Contract with Customer [Abstract]

REVENUE RECOGNITION

We disaggregate our revenues by applicable service line as follows: collection, landfill, transfer, customer solutions, recycling, organics, transportation and landfill gas-to-energy.

Collection

Collection revenues are principally generated by providing waste collection and disposal services to our customers. Services may be provided as needed or as scheduled. We derive a substantial portion of our collection revenues from commercial and industrial services, which typically have a standard contract duration of three years, along with municipal services that are generally performed pursuant to contracts with municipalities with varying terms. The majority of our residential collection services are performed on a subscription basis with individual households.

Landfill

Landfill disposal services primarily consist of receiving some form of acceptable solid waste materials at one of our landfills and appropriately disposing of it. Landfill customers are typically charged a tipping fee on a per ton basis for disposing of their solid waste at our disposal facilities. In general, these fees are variable in nature.

Transfer Station

Transfer station disposal services primarily consist of receiving some form of acceptable solid waste materials at one of our transfer stations and appropriately disposing of it by transporting it to an appropriate disposal site. Transfer station customers are charged a tipping fee on a per ton basis for disposing of their solid waste at our transfer stations. In general, these fees are variable in nature.

Transportation

Transportation services consist of the transportation of large volumes of waste or recycled materials from a customer designated location to another location or disposal facility. Transportation customers are charged a fee on a per ton basis for transporting and/or disposal of the materials. In general, these fees are variable in nature.

Recycling

Recycling services primarily consist of the collection and/or receipt of recycled materials at one of our materials recovery facilities; the processing or sorting of the recycled materials; and the disposal or sale of the recycled materials. Revenues from recycling services consist of revenues derived from municipalities and customers in the form of processing fees, tipping fees and commodity sales. In brokerage arrangements, we act as an agent that facilitates the sale of recyclable materials between an inbound customer and an outbound customer. Revenues from the brokerage of recycled materials are recognized on a net basis at the time of shipment. In general, these fees are variable in nature.

Customer Solutions

Customer solutions services consist of commercial and industrial offerings. Commercial services consist of traditional collection, disposal and recycling services provided to large account multi-site customers. Industrial services consist of overall resource management services provided to large and complex organizations, such as universities, hospitals, manufacturers and municipalities, delivering a wide range of environmental services and zero waste solutions.

Organics

Organics services primarily consist of the collection and/or receipt of organic materials at one of our processing or disposal facilities; the processing of the organic materials; and the disposal or sale of the organic materials.

Landfill Gas-to-Energy

Landfill gas-to-energy services primarily consist of the generation and sale of electricity from landfill gas-to-energy facilities located at certain of our landfills; the reservation of electric generating capacity to be used by a customer on demand; and the sale of RECs.

A table of revenues disaggregated by service line and timing of revenue recognition by operating segment follows:

Fiscal Year Ended December 31, 2019



	Eastern		Western		Recycling		Other		Total Revenues
Collection	$	154,805	$	223,034	$	—	$	—	$	377,839
Landfill	19,362		73,657		—		—		93,019
Transfer	44,413		31,725		—		—		76,138
Customer solutions	—		—		—		79,457		79,457


Recycling	5		1,486		42,820		—		44,311


Organics	—		—		—		56,326		56,326
Transportation	—		10,811		—		1,813		12,624


Landfill gas-to-energy	890		2,686		—		—		3,576
Total revenues	$	219,475	$	343,399	$	42,820	$	137,596	$	743,290

Transferred at a point-in-time	$	159	$	921	$	19,738	$	3,468	$	24,286
Transferred over time	219,316		342,478		23,082		134,128		719,004
Total revenues	$	219,475	$	343,399	$	42,820	$	137,596	$	743,290

Fiscal Year Ended December 31, 2018



	Eastern		Western		Recycling		Other		Total Revenues
Collection	$	136,661	$	170,278	$	—	$	—	$	306,939
Landfill	28,419		66,567		—		—		94,986
Transfer	39,991		27,592		—		—		67,583
Customer solutions	—		—		—		67,464		67,464


Recycling	5		3,823		42,191		—		46,019


Organics	—		—		—		54,174		54,174
Transportation	—		14,270		—		4,096		18,366


Landfill gas-to-energy	1,397		3,732		—		—		5,129
Total Revenues	$	206,473	$	286,262	$	42,191	$	125,734	$	660,660

Transferred at a point-in-time	$	648	$	1,145	$	27,260	$	3,921	$	32,974
Transferred over time	205,825		285,117		14,931		121,813		627,686
Total revenues	$	206,473	$	286,262	$	42,191	$	125,734	$	660,660

BUSINESS COMBINATIONS

12 Months Ended

Dec. 31, 2019

Business Combinations [Abstract]

BUSINESS COMBINATIONS

BUSINESS COMBINATIONSIn fiscal year 2019, we acquired nine businesses: three tuck-in solid waste collection businesses in our Eastern region; and four tuck-in solid waste collection businesses, a business comprised of solid waste collection, transfer and recycling operations, and a business comprised of solid waste hauling and transfer assets in our Western region. In fiscal year 2018 we acquired nine businesses: six solid waste collection businesses and one transfer business in our Western region; and two businesses comprised of solid waste collection and transfer operations in our Eastern region. In fiscal year 2017, we acquired four businesses: one solid waste collection business in our Eastern region; and three solid waste collection businesses in our Western region. The operating results of these businesses are included in the accompanying audited consolidated statements of operations from each date of acquisition, and the purchase price has been allocated to the net assets acquired based on fair values at each date of acquisition, with the residual amounts recorded as goodwill. Acquired intangible assets other than goodwill that are subject to amortization include client lists and non-compete covenants. These are amortized over a five to ten-year period from the date of acquisition. All amounts recorded to goodwill in fiscal years 2019 and 2018, except goodwill related to certain acquisitions are expected to be deductible for tax purposes.

The purchase price paid for these acquisitions and the allocation of the purchase price is as follows:


	Fiscal Year Ended December 31,
	2019		2018		2017
Purchase Price:
Cash used in acquisitions, net of cash acquired	$	72,118	$	86,686	$	4,823
Notes payable	2,714		—		2,400
Class A common stock issued	—		4,258		—
Other non-cash considerations	5,470		—		101
Contingent consideration and holdbacks	1,875		8,521		736
Total	82,177		99,465		8,060
Current assets	2,051		3,276		93
Non-current assets	367		—		—
Land	2,487		—		—
Buildings	5,422		7,889		—
Equipment	20,482		23,882		2,994
Other liabilities, net	(3,122)		(4,708)		(49)
Deferred tax liability	(2,385)		(937)		—
Intangible assets	31,171		29,934		2,334
Fair value of assets acquired and liabilities assumed	56,473		59,336		5,372
Excess purchase price to be allocated to goodwill	$	25,704	$	40,129	$	2,688

The following unaudited pro forma combined information shows our operational results as though each of the acquisitions completed had occurred as of January 1, 2017.


	Fiscal Year Ended December 31,
	2019		2018		2017
Revenues	$	773,845	$	752,916	$	708,909
Operating income (loss)	$	56,997	$	49,893	$	(1,061)
Net income (loss)	$	33,893	$	12,167	$	(15,291)
Basic weighted average shares outstanding	47,226		42,688		41,846
Basic earnings (loss) per common share	$	0.72	$	0.29	$	(0.37)
Diluted weighted average shares outstanding	47,966		44,168		41,846
Diluted earnings (loss) per common share	$	0.71	$	0.28	$	(0.37)

The pro forma results have been prepared for comparative purposes only and are not necessarily indicative of the actual results of operations had the acquisitions taken place as of January 1, 2017 or the results of our future operations. Furthermore, the pro forma results do not give effect to all cost savings or incremental costs that may occur as a result of the integration and consolidation of the completed acquisitions.

RESTRICTED ASSETS

12 Months Ended

Dec. 31, 2019

Receivables [Abstract]

RESTRICTED ASSETS

Restricted assets consist of investment securities held in trust on deposit with various banks as collateral for our obligations relative to our landfill final capping, closure and post-closure costs.

A summary of restricted assets is as follows:


	December 31,
Non Current:	2019		2018




Restricted investment securities - landfill closure	$	1,586	$	1,248

PROPERTY, PLANT AND EQUIPMENT

12 Months Ended

Dec. 31, 2019

Property, Plant and Equipment [Abstract]

PROPERTY, PLANT AND EQUIPMENT

A summary of property, plant and equipment is as follows:


	December 31,
	2019		2018
Land	$	28,703	$	25,490
Landfills	578,814		544,663
Landfill operating lease contracts (1)	—		121,877
Finance lease right-of-use assets (2)	24,038		—
Buildings and improvements	161,316		150,885
Machinery and equipment	168,735		153,222
Rolling stock	183,145		163,758
Containers	143,948		123,383
	1,288,699		1,283,278
Less: accumulated depreciation and amortization (1)	(844,874)		(878,701)
	$	443,825	$	404,577

(1)Upon the adoption of Topic 842 effective January 1, 2019, landfill operating lease contracts payments that were previously capitalized as property, plant and equipment were prospectively reclassified, along with related accumulated depreciation, to operating lease right-of-use assets.

(2)Upon the adoption of Topic 842 effective January 1, 2019, property, plant and equipment pertaining to finance leases that were previously capitalized in other property, plant and equipment groupings were prospectively reclassified to finance lease right-of-use assets.

Depreciation expense for fiscal years 2019, 2018 and 2017 was $45,060, $35,351 and $32,131, respectively. Landfill amortization expense for fiscal years 2019, 2018 and 2017 was $27,512, $31,841 and $27,910, respectively. Depletion expense on landfill operating lease contracts for fiscal years 2018 and 2017 was $9,724 and $9,646, respectively, and was recorded in cost of operations. See Note 8, Leases for further disclosure over lease costs and other lease information.

LEASES

12 Months Ended

Dec. 31, 2019

Leases [Abstract]

LEASES

A schedule of lease costs and other lease information follows:


	Fiscal Year Ended December 31, 2019
Lease cost:
Amortization of right-of-use assets	$	2,122
Interest expense	767
Fixed lease cost - vehicles, equipment and property	9,560
Fixed lease cost - landfill operating leases	7,711
Fixed lease cost	17,271
Short-term lease cost	3,878
Variable lease cost	190
Total lease cost	$	24,228

Other information:
Cash paid for amounts included in the measurement of lease liabilities:
Financing cash flows for finance leases	$	2,601
Operating cash flows for operating leases	$	13,840
Right-of-use assets obtained in exchange for new finance lease liabilities	$	9,433
Right-of-use assets obtained in exchange for new operating lease liabilities	$	3,351

	December 31, 2019
Weighted-average remaining lease term - finance leases (years)	6.5
Weighted-average remaining lease term - operating leases (years)	12.0
Weighted-average discount rate - finance leases	5.0		%
Weighted-average discount rate - operating leases	5.1		%

Estimated minimum future lease obligations are as follows:


	Operating Leases		Finance Leases
Fiscal year ending December 31, 2020	$	13,210	$	4,141
Fiscal year ending December 31, 2021	11,238		3,758
Fiscal year ending December 31, 2022	8,848		3,163
Fiscal year ending December 31, 2023	6,905		2,994
Fiscal year ending December 31, 2024	6,251		2,891
Thereafter	63,717		5,332
Total lease payments	110,169		22,279
Less: interest expense	(30,104)		(3,915)
Lease liability balance	$	80,065	$	18,364

LEASES

A schedule of lease costs and other lease information follows:


	Fiscal Year Ended December 31, 2019
Lease cost:
Amortization of right-of-use assets	$	2,122
Interest expense	767
Fixed lease cost - vehicles, equipment and property	9,560
Fixed lease cost - landfill operating leases	7,711
Fixed lease cost	17,271
Short-term lease cost	3,878
Variable lease cost	190
Total lease cost	$	24,228

Other information:
Cash paid for amounts included in the measurement of lease liabilities:
Financing cash flows for finance leases	$	2,601
Operating cash flows for operating leases	$	13,840
Right-of-use assets obtained in exchange for new finance lease liabilities	$	9,433
Right-of-use assets obtained in exchange for new operating lease liabilities	$	3,351

	December 31, 2019
Weighted-average remaining lease term - finance leases (years)	6.5
Weighted-average remaining lease term - operating leases (years)	12.0
Weighted-average discount rate - finance leases	5.0		%
Weighted-average discount rate - operating leases	5.1		%

Estimated minimum future lease obligations are as follows:


	Operating Leases		Finance Leases
Fiscal year ending December 31, 2020	$	13,210	$	4,141
Fiscal year ending December 31, 2021	11,238		3,758
Fiscal year ending December 31, 2022	8,848		3,163
Fiscal year ending December 31, 2023	6,905		2,994
Fiscal year ending December 31, 2024	6,251		2,891
Thereafter	63,717		5,332
Total lease payments	110,169		22,279
Less: interest expense	(30,104)		(3,915)
Lease liability balance	$	80,065	$	18,364

GOODWILL AND INTANGIBLE ASSETS

12 Months Ended

Dec. 31, 2019

Goodwill and Intangible Assets Disclosure [Abstract]

GOODWILL AND INTANGIBLE ASSETS

A summary of the activity and balances related to goodwill by reporting segment is as follows:


	December 31, 2018		Acquisitions		Other (1)		December 31, 2019
Eastern	$	28,154	$	2,566	$	—	$	30,720
Western	120,536		23,138		(2,619)		141,055
Recycling	12,315		—		—		12,315
Other	1,729		—		—		1,729
Total	$	162,734	$	25,704	$	(2,619)	$	185,819

(1)Relates to unregistered sale of Class A common stock that was previously held in escrow and released to us for liquidation. See Note 13, Stockholders' Equity (Deficit) for additional disclosure.


	December 31, 2017		Acquisitions		December 31, 2018
Eastern	$	19,192	$	8,962	$	28,154
Western	89,369		31,167		120,536
Recycling	12,315		—		12,315
Other	1,729		—		1,729
Total	$	122,605	$	40,129	$	162,734

A summary of intangible assets is as follows:


	Covenants Not-to-Compete		Client Lists		Total
Balance, December 31, 2019
Intangible assets	$	26,162	$	71,122	$	97,284
Less accumulated amortization	(18,968)		(19,595)		(38,563)
	$	7,194	$	51,527	$	58,721


	Covenants Not-to-Compete		Client Lists		Total
Balance, December 31, 2018
Intangible assets	$	21,750	$	44,363	$	66,113
Less accumulated amortization	(17,584)		(13,762)		(31,346)
	$	4,166	$	30,601	$	34,767

Intangible amortization expense for fiscal years 2019, 2018 and 2017 was $7,218, $3,316 and $2,061, respectively.

The intangible amortization expense estimated for the five fiscal years following fiscal year 2019 and thereafter is as follows:



Estimated Future Amortization Expense as of December 31, 2019
Fiscal year ending December 31, 2020	$	8,222
Fiscal year ending December 31, 2021	$	6,826
Fiscal year ending December 31, 2022	$	6,188
Fiscal year ending December 31, 2023	$	5,993
Fiscal year ending December 31, 2024	$	6,974
Thereafter	$	24,518

FINAL CAPPING, CLOSURE AND POST-CLOSURE COSTS

12 Months Ended

Dec. 31, 2019

Asset Retirement Obligation Disclosure [Abstract]

FINAL CAPPING, CLOSURE AND POST-CLOSURE COSTS

FINAL CAPPING, CLOSURE AND POST-CLOSURE COSTSAccrued final capping, closure and post-closure costs include the current and non-current portion of costs associated with obligations for final capping closure and post-closure of our landfills. We estimate our future final capping, closure and post-closure costs in order to determine the final capping, closure and post-closure expense per ton of waste placed into each landfill as further described in Note 3, Summary of Significant Accounting Policies. The anticipated time frame for paying these costs varies based on the remaining useful life of each landfill, as well as the duration of the post-closure monitoring period.

The changes to accrued final capping, closure and post-closure liabilities are as follows:


	Fiscal Year Ended December 31,
	2019		2018
Beginning balance	$	73,075	$	62,290
Obligations incurred	2,549		3,713
Revisions in estimates (1)	(1,538)		5,095
Accretion expense	6,227		5,556
Obligations settled (2)	(8,386)		(3,579)
Ending balance	$	71,927	$	73,075

(1)Relates to changes in estimates and assumptions concerning anticipated waste flow, cost and timing of future final capping, closure and post-closure activities at certain landfills, including the Subtitle D landfill in Southbridge, Massachusetts ("Southbridge Landfill"), as well as changes to expansion airspace at other landfills. See Note 17, Other Items and Charges for disclosure regarding Southbridge Landfill.

(2)Includes amounts paid and amounts that are being processed through accounts payable as a part of our disbursement cycle.

DEBT

12 Months Ended

Dec. 31, 2019

Debt Disclosure [Abstract]

DEBT

A summary of debt is as follows:


	December 31,
	2019		2018
Senior Secured Credit Facility:
Revolving Credit Facility due May 2023 ("Revolving Credit Facility"); bearing interest at LIBOR plus 1.75%	$	26,900	$	69,600
Term Loan A Facility due May 2023 (Term Loan Facility"); bearing interest at LIBOR plus 1.75%	350,000		350,000
Tax-Exempt Bonds:
New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014 ("New York Bonds 2014") due December 2044 - fixed rate interest period through 2029; bearing interest at 2.875%	25,000		25,000
New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014R-2 ("New York Bonds 2014R-2") due December 2044 - fixed rate interest period through 2026; bearing interest at 3.125%	15,000		15,000
Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2005R-3 ("FAME Bonds 2005R-3") due January 2025 - fixed rate interest period through 2025; bearing interest at 5.25%	25,000		25,000
Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2015R-1 ("FAME Bonds 2015R-1") due August 2035 - fixed rate interest period through 2025; bearing interest at 5.125%	15,000		15,000
Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2015R-2 ("FAME Bonds 2015R-2") due August 2035 - fixed rate interest period through 2025; bearing interest at 4.375%	15,000		15,000
Vermont Economic Development Authority Solid Waste Disposal Long-Term Revenue Bonds Series 2013 ("Vermont Bonds") due April 2036 - fixed rate interest period through 2028; bearing interest at 4.625%	16,000		16,000
Business Finance Authority of the State of New Hampshire Solid Waste Disposal Revenue Bonds Series 2013 ("New Hampshire Bonds") due April 2029 - fixed rate interest period through 2029; bearing interest at 2.95%	11,000		11,000
Other:
Finance leases maturing through December 2107; bearing interest at a weighted average of 5.0%	18,364		11,248
Notes payable maturing through June 2027; bearing interest at a weighted average of 3.5%	5,464		2,401
Principal amount of debt	522,728		555,249
Less—unamortized discount and debt issuance costs (1)	9,406		10,950
Debt less unamortized discount and debt issuance costs	513,322		544,299
Less—current maturities of debt	4,301		2,298
	$	509,021	$	542,001

(1)A summary of unamortized discount and debt issuance costs by debt instrument follows:


	December 31,
	2019		2018
Revolving Credit Facility and Term Loan Facility (collectively, the "Credit Facility")	$	5,478	$	7,118
New York Bonds 2014	1,057		847
New York Bonds 2014R-2	390		450
FAME Bonds 2005R-3	432		517
FAME Bonds 2015R-1	552		622
FAME Bonds 2015R-2	417		493
Vermont Bonds	541		595
New Hampshire Bonds	539		308
	$	9,406	$	10,950

Credit Facility

In fiscal year 2018, we entered into a credit agreement ("Credit Agreement"), which provides for a $350,000 aggregate principal amount Term Loan Facility and a $200,000 Revolving Credit Facility. The net proceeds from this transaction were used to repay in full the amounts outstanding of the $350,000 aggregate principal amount term loan B facility ("Term Loan B Facility") and the $160,000 revolving line of credit facility plus accrued and unpaid interest thereon and to pay related transaction expenses. We have the right to request, at our discretion, an increase in the amount of loans under the Credit Facility by an aggregate amount $125,000, subject to the terms and conditions set forth in the Credit Agreement.

The Credit Facility has a 5-year term and bears interest at a rate of LIBOR plus 1.75%, which can be reduced to a rate of LIBOR plus 1.25% upon us reaching a consolidated net leverage ratio of less than 2.25x. The Credit Facility is guaranteed jointly and severally, fully and unconditionally by all of our significant wholly-owned subsidiaries and secured by substantially all of our assets. As of December 31, 2019, further advances were available under the Credit Facility in the amount of $148,575. The available amount is net of outstanding irrevocable letters of credit totaling $24,525, at which date no amount had been drawn.

The Credit Agreement requires us to maintain a minimum interest coverage ratio and a maximum consolidated net leverage ratio, to be measured at the end of each fiscal quarter. As of December 31, 2019, we were in compliance with the covenants contained in the Credit Agreement. In addition to these financial covenants, the Credit Agreement also contains a number of important customary affirmative and negative covenants which restrict, among other things, our ability to sell assets, incur additional debt, create liens, make investments, and pay dividends. We do not believe that these restrictions impact our ability to meet future liquidity needs. An event of default under any of our debt agreements could permit some of our lenders, including the lenders under the Credit Facility, to declare all amounts borrowed from them to be immediately due and payable, together with accrued and unpaid interest, or, in the case of the Credit Facility, terminate the commitment to make further credit extensions thereunder, which could, in turn, trigger cross-defaults under other debt obligations. If we were unable to repay debt to our lenders, or were otherwise in default under any provision governing our outstanding debt obligations, our secured lenders could proceed against us and against the collateral securing that debt.

Tax-Exempt Financings

New York Bonds. In fiscal year 2019, we completed the remarketing of $25,000 aggregate principal amount of New York Bonds 2014. As of December 31, 2019, we had outstanding $25,000 aggregate principal amount of New York Bonds 2014 and $15,000 aggregate principal amount of New York Bonds 2014R-2 issued by the New York State Environmental Facilities Corporation under the indenture dated December 1, 2014 (collectively, the “New York Bonds”). The New York Bonds 2014 accrue interest at 2.875% per annum through December 2, 2029, at which time they may be converted from a fixed rate to a variable rate. The New York Bonds 2014R-2 accrue interest at 3.125% per annum through May 31, 2026, at which time they may be converted from a fixed rate to a variable rate. The New York Bonds, which are unsecured and guaranteed jointly and severally, fully and unconditionally by all of our significant wholly-owned subsidiaries, require interest payments on June 1 and December 1 of each year and mature on December 1, 2044. We borrowed the proceeds of the New York Bonds to finance or refinance certain capital projects in the state of New York and to pay certain costs of issuance of the New York Bonds.

Maine Bonds. In fiscal year 2018, we completed the issuance of $15,000 aggregate principal amount of FAME Bonds 2015R-2. As of December 31, 2019, we had outstanding $25,000 aggregate principal amount of FAME Bonds 2005R-3, $15,000 aggregate principal amount of FAME Bonds 2015R-1, and $15,000 aggregate principal amount of FAME Bonds 2015R-2 (collectively, the "FAME Bonds"). The FAME Bonds 2005R-3 accrue interest at 5.25% per annum, and interest is payable semiannually on February 1 and August 1 of each year until such bonds mature on January 1, 2025. The FAME Bonds 2015R-1 accrue interest at 5.125% per annum through August 1, 2025, at which time they may be converted from a fixed to a variable rate, and interest is payable semiannually on February 1 and August 1 of each year until the FAME Bonds 2015R-1 mature on August 1, 2035. The FAME Bonds 2015R-2 accrue interest at 4.375% per annum through July 31, 2025, at which time they may be converted from a fixed to a variable rate, and interest is payable semiannually on May 1 and November 1 of each year until the FAME Bonds 2015R-2 mature on August 1, 2035. The FAME Bonds are unsecured and guaranteed jointly and severally, fully and unconditionally by all of our significant wholly-owned subsidiaries. We borrowed the proceeds of the offering of the FAME Bonds to finance or refinance the costs of certain of our solid waste landfill facilities and solid waste collection, organics and transfer, recycling and hauling facilities, and to pay certain costs of the issuance of the FAME Bonds.

Vermont Bonds. In fiscal year 2018, we completed the remarketing of $16,000 aggregate principal amount of 4.75% fixed rate senior unsecured Vermont Bonds. As of December 31, 2019, we had outstanding $16,000 aggregate principal amount of Vermont Bonds. The Vermont Bonds, which are guaranteed jointly and severally, fully and unconditionally by all of our significant wholly-owned subsidiaries, accrue interest at 4.625% per annum through April 2, 2028, after which time there is a mandatory tender, and interest is payable semiannually on May 1 and November 1 of each year. The Vermont Bonds mature on April 1, 2036. We borrowed the proceeds of the Vermont Bonds to finance or refinance certain qualifying property, plant and equipment assets purchased in the state of Vermont.

New Hampshire Bonds. In fiscal year 2019, we completed the remarketing of $11,000 aggregate principal amount of senior unsecured New Hampshire Bonds. As of December 31, 2019, we had outstanding $11,000 aggregate principal amount of New Hampshire Bonds. The New Hampshire Bonds, which are guaranteed jointly and severally, fully and unconditionally by all of our significant wholly-owned subsidiaries, accrue interest at 2.95% per annum through maturity on April 1, 2029 and interest. During the fixed interest rate period, the New Hampshire Bonds are not supported by a letter of credit. Interest is payable on April 1 and October 1 of each year. We borrowed the proceeds of the New Hampshire Bonds to finance or refinance certain qualifying property, plant and equipment assets purchased in the state of New Hampshire.

Loss on Debt Extinguishment

In order to lower our borrowing costs and reduce our market risk we completed the following transactions that resulted in a loss on debt extinguishment in fiscal years 2019, 2018 and 2017 of $0, $7,352 and $517, respectively:

•the write-off of debt issuance costs and unamortized discount, in the case of our Term Loan B Facility in fiscal year 2018, associated with the refinancing of our previously outstanding senior secured credit facility in fiscal year 2018 and an amendment to our previously outstanding senior secured credit facility in fiscal year 2017: and

•the write-off of debt issuance costs in connection with the remarketing of our Vermont Bonds in fiscal year 2018 and the remarketing of our Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2005R-1 (“FAME Bonds 2005R-1”) and Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2005R-2 (“FAME Bonds 2005R-2”) into the FAME Bonds 2005R-3 in fiscal year 2017.

Interest Expense

The components of interest expense are as follows:


	Fiscal Year Ended December 31,
	2019		2018		2017
Interest expense on long-term debt and finance leases	$	22,553	$	23,431	$	22,060
Amortization of debt issuance costs and discount on long-term debt	2,293		2,449		2,692
Letter of credit fees	519		554		703
Less: capitalized interest	(263)		(140)		(295)
Total interest expense	$	25,102	$	26,294	$	25,160

Cash Flow Hedges

Our strategy to reduce exposure to interest rate risk involves entering into interest rate derivative agreements to hedge against adverse movements in interest rates related to the variable rate portion of our long-term debt. We enter into interest rate derivative agreements to manage exposure to fluctuations in interest rates related to variable rate interest payments of our long-term debt. As of both December 31, 2019, and December 31, 2018, our interest rate derivative agreements had a total notional amount of $190,000. We receive interest based on the 1-month LIBOR index, restricted by a floor in certain instances, and pay interest at a weighted average rate of approximately 2.5% as of both December 31, 2019 and December 31, 2018. The agreements mature between February 2021 and May 2023.

In fiscal year 2019, we entered into interest rate derivative agreements with a total notional amount of $65,000 that will serve to replace existing interest rate derivative agreements upon their expiration between February 2021 and February 2022. These forward starting interest rate derivative agreements mature between February 2026 and February 2027. We receive interest based on the 1-month LIBOR index, restricted by floor, and pay interest at a weighted average rate of approximately 1.8%.

We have designated these derivative instruments as highly effective cash flow hedges, and therefore the change in fair value is recorded in our stockholders’ equity (deficit) as a component of accumulated other comprehensive loss and included in interest expense at the same time as interest expense is affected by the hedged transactions. Differences paid or received over the life of the agreements are recorded as additions to or reductions of interest expense on the underlying debt and included in cash flows from operating activities.

A summary of the effect of cash flow hedges related to derivative instruments on the consolidated balance sheet follows:


		Fair Value
	Balance Sheet Location	December 31, 2019		December 31, 2018
Interest rate swaps	Other current assets	$	—	$	338
Interest rate swaps	Other non-current assets	—		482
Total		$	—	$	820

Interest rate swaps	Other accrued liabilities	$	1,824	$	387
Interest rate swaps	Other long-term liabilities	3,603		1,555
Total		$	5,427	$	1,942

Interest rate swaps	Accumulated other comprehensive loss, net	$	(5,929)	$	(1,196)
Interest rate swaps - tax provision	Accumulated other comprehensive loss, net	(112)		(112)
		$	(6,041)	$	(1,308)

A summary of the amount of gain or (loss) on cash flow hedging relationships related to interest rate swaps reclassified from accumulated other comprehensive loss, net into earnings follows:


	Fiscal Year Ended December 31,
	2019		2018		2017
Statement of Operations Location	(Expense) Income
Interest expense	$	(553)	$	(363)	$	(421)

Fair Value of Debt

As of December 31, 2019, the fair value of our fixed rate debt, including the FAME Bonds, Vermont Bonds, New York Bonds and New Hampshire Bonds was approximately $131,357 and the carrying value was $122,000. The fair value of the FAME Bonds, Vermont Bonds, New York Bonds and New Hampshire Bonds is considered to be Level 2 within the fair value hierarchy as the fair value is determined using market approach pricing provided by a third-party that utilizes pricing models and pricing systems, mathematical tools and judgment to determine the evaluated price for the security based on the market information of each of the bonds or securities with similar characteristics.

As of December 31, 2019, the carrying value of our Term Loan Facility was $350,000 and the carrying value of our Revolving Credit Facility was $26,900. Their fair values are based on current borrowing rates for similar types of borrowing arrangements, or Level 2 inputs, and approximate their carrying values.

Although we have determined the estimated fair value amounts of the FAME Bonds, Vermont Bonds, New York Bonds and New Hampshire Bonds using available market information and commonly accepted valuation methodologies, a change in available market information, and/or the use of different assumptions and/or estimation methodologies could have a material effect on the estimated fair values. These amounts have not been revalued, and current estimates of fair value could differ significantly from the amounts presented.

Future Maturities of Debt

Aggregate principal maturities of debt are as follows:



Estimated Future Payments as of December 31, 2019
Fiscal year ending December 31, 2020	$	4,300
Fiscal year ending December 31, 2021	3,593
Fiscal year ending December 31, 2022	5,358
Fiscal year ending December 31, 2023	379,945
Fiscal year ending December 31, 2024	2,893
Thereafter	126,639
	$	522,728

COMMITMENTS AND CONTINGENCIES

12 Months Ended

Dec. 31, 2019

Commitments and Contingencies Disclosure [Abstract]

COMMITMENTS AND CONTINGENCIES

In the ordinary course of our business and as a result of the extensive governmental regulation of the solid waste industry, we are subject to various judicial and administrative proceedings involving state and local agencies. In these proceedings, an agency may seek to impose fines or to revoke or deny renewal of an operating permit held by us. From time to time, we may also be subject to actions brought by special interest or other groups, adjacent landowners or residents in connection with the permitting and licensing of landfills and transfer stations, or allegations of environmental damage or violations of the permits and licenses pursuant to which we operate. In addition, we may be named defendants in various claims and suits pending for alleged damages to persons and property, alleged violations of certain laws and alleged liabilities arising out of matters occurring during the ordinary operation of a waste management business.

In accordance with FASB ASC 450 - Contingencies, we accrue for legal proceedings, inclusive of legal costs, when losses become probable and reasonably estimable. As of the end of each applicable reporting period, we review each of our legal proceedings to determine whether it is probable, reasonably possible or remote that a liability has been incurred and, if it is at least reasonably possible, whether a range of loss can be reasonably estimated under the provisions of FASB ASC 450-20. In instances where we determine that a loss is probable and we can reasonably estimate a range of loss we may incur with respect to such a matter, we record an accrual for the amount within the range that constitutes our best estimate of the possible loss. If we are able to reasonably estimate a range, but no amount within the range appears to be a better estimate than any other, we record an accrual in the amount that is the low end of such range. When a loss is reasonably possible, but not probable, we will not record an accrual, but we will disclose our estimate of the possible range of loss where such estimate can be made in accordance with FASB ASC 450-20.

Environmental Remediation Liability (including related litigation)

We are subject to liability for environmental damage, including personal injury and property damage, that our solid waste, recycling and power generation facilities may cause to neighboring property owners, particularly as a result of the contamination of drinking water sources or soil, possibly including damage resulting from conditions that existed before we acquired the facilities. We may also be subject to liability for similar claims arising from off-site environmental contamination caused by pollutants or hazardous substances if we or our predecessors arrange or arranged to transport, treat or dispose of those materials. The following matters represent our material outstanding claims.

Southbridge Recycling & Disposal Park, Inc.

In October 2015, our Southbridge Recycling and Disposal Park, Inc. (“SRD”) subsidiary reported to the Massachusetts Department of Environmental Protection (“MADEP”) results of analysis of samples collected pursuant to our existing permit from private drinking water wells located near the Town of Southbridge, Massachusetts (“Town”) Landfill (“Southbridge Landfill”), which was operated by SRD and later closed in November 2018 when Southbridge Landfill reached its final capacity. Those results indicated the presence of contaminants above the levels triggering notice and response obligations under MADEP regulations. In response to those results, we are carrying out an Immediate Response Action pursuant to Massachusetts General Law Chapter 21E (the "Charlton 21E Obligations") pursuant to state law. Further, we have implemented a plan to analyze and better understand the groundwater near the Southbridge Landfill and we are investigating with the objective of identifying the source or sources of the elevated levels of contamination measured in the well samples. If it is determined that some or all of the contamination originated at the Southbridge Landfill, we will work with the Town (the Southbridge Landfill owner and the former operator of an unlined portion of the Southbridge Landfill, which was used prior to our operation of a double-lined portion of the Southbridge Landfill commencing in 2004) to evaluate and allocate the liabilities related to the Charlton 21E Obligations. In July 2016, we sent correspondence to the Town pursuant to Chapter 21E of Massachusetts General Laws demanding that the Town reimburse us for the environmental response costs we had spent and that the Town be responsible for all such costs in the future, as well as any other costs or liabilities resulting from the release of contaminants from the unlined portion of the Southbridge Landfill. The Town responded in September 2016, denying that the Southbridge Landfill is the source of such contamination, and claiming that if it is, that we may owe an indemnity to the Town pursuant to the Operating Agreement between us and the Town dated May 29, 2007, as amended. We entered into a Tolling Agreement with the Town to delay any further administrative or legal actions until our work with MADEP more specifically defines the parties’ responsibilities for the Charlton 21E Obligations, if any. Please see below for further discussion of our relationship with the Town regarding the Charlton 21E Obligations.

In February 2016, we and the Town received a Notice of Intent to Sue under the Resource Conservation and Recovery Act ("RCRA") from a law firm purporting to represent residents proximate to the Southbridge Landfill (“Residents”), indicating its intent to file suit against us on behalf of the Residents alleging the groundwater contamination originated from the Southbridge Landfill. In February 2017, we received an additional Notice of Intent to Sue from the National Environmental Law Center under the Federal Clean Water Act ("CWA") and RCRA (collectively the “Acts”) on behalf of Environment America, Inc., d/b/a Environment Massachusetts, and Toxics Action Center, Inc., which have referred to themselves as the Citizen Groups. The Citizen Groups alleged that we had violated the Acts, and that they intended to seek appropriate relief in federal court for those alleged violations. On or about June 9, 2017, a lawsuit was filed against us, SRD and the Town in the United States District Court for the District of Massachusetts (the “Massachusetts Court”) by the Citizen Groups and the Residents alleging violations of the Acts (the “Litigation”), and demanding a variety of remedies under the Acts, including fines, remediation, mitigation and costs of litigation, and remedies for violations of Massachusetts civil law related to personal and property damages, including remediation, diminution of property values, compensation for lost use and enjoyment of properties, enjoinment of further operation of the Southbridge Landfill, and costs of litigation, plus interest on any damage award, on behalf of the Residents. We believe the Litigation to be factually inaccurate, and without legal merit, and we and SRD intend to vigorously defend the Litigation. Nevertheless, we believe it is reasonably possible that a loss will occur as a result of the Litigation although an estimate of loss cannot be reasonably provided at this time. We also continue to believe the Town should be responsible for costs or liabilities associated with the Litigation relative to alleged contamination originating from the unlined portion of the Southbridge Landfill, although there can be no assurance that we will not be required to incur some or all of such costs and liabilities.

In December 2017, we filed a Motion to Dismiss the Litigation, and on October 1, 2018, the Massachusetts Court granted our Motion to Dismiss, and accordingly, dismissed the Citizen Groups claims under the Acts. The Massachusetts Court has retained jurisdiction of the Residents claims. The Citizen Groups intend to appeal the Massachusetts Court’s decision to grant our Motion to Dismiss. The Residents moved for a stay of their case until the Citizen Groups appealed. We opposed the stay and in March 2019, the Massachusetts Court denied the Residents motion for a stay. We are in active discovery in the Residents case.

We entered into an Administrative Consent Order on April 26, 2017 (the “ACO”), with MADEP, the Town, and the Town of Charlton, committing us to equally share the costs with MADEP, of up to $10,000 ($5,000 each) for the Town to install a municipal waterline in the Town of Charlton ("Waterline"). Upon satisfactory completion of that Waterline, and other matters covered by the ACO, we and the Town will be released by MADEP from any future responsibilities for the Charlton 21E Obligations. We also entered into an agreement with the Town on April 28, 2017 entitled the “21E Settlement and Water System Construction Funding Agreement” (the “Waterline Agreement”), wherein we and the Town released each other from claims arising from the Charlton 21E Obligations. Pursuant to the Waterline Agreement, the Town will issue a twenty (20) year bond for our portion of the Waterline costs (up to $5,000). We have agreed to reimburse the Town for periodic payments under such bond. Construction of the waterline is complete and homeowners are relying on municipal water supply. Remaining aspects of the project are minor and are expected to be completed in early 2020. Bond reimbursement to the Town will commence in the fiscal year ending December 31, 2020.

We have recorded an environmental remediation liability related to our obligation associated with installation of the Waterline in other accrued liabilities and other long-term liabilities. We inflate the estimated costs in current dollars to the expected time of payment and discount the total cost to present value using a risk-free interest rate of 1.9%. Our expenditures could be significantly higher if costs exceed estimates.

A summary of the changes to the environmental remediation liability associated with the Southbridge Landfill follows:



	Fiscal Year Ended December 31,
	2019		2018
Beginning balance	$	5,173	$	5,936
Accretion expense	124		—
Obligations incurred	—		152

Obligations settled (1)	(701)		(915)
Ending balance	$	4,596	$	5,173

(1)Includes amounts that are being processed through accounts payable as a part of our disbursements cycle.

We completed the first phase of landfill capping and closure in fiscal year 2019 at the Southbridge Landfill and are actively seeking approval from MADEP to close and cap the remainder of the landfill.

The costs and liabilities we may be required to incur in connection with the foregoing Southbridge Landfill matters could be material to our results of operations, our cash flows and our financial condition.

Potsdam Environmental Remediation Liability

On December 20, 2000, the State of New York Department of Environmental Conservation (“DEC”) issued an Order on Consent (“Order”) which named Waste-Stream, Inc. (“WSI”), our subsidiary, General Motors Corporation (“GM”) and Niagara Mohawk Power Corporation (“NiMo”) as Respondents. The Order required that the Respondents undertake certain work on a 25-acre scrap yard and solid waste transfer station owned by WSI in Potsdam, New York, including the preparation of a Remedial Investigation and Feasibility Study (“Study”). A draft of the Study was submitted to the DEC in January 2009 (followed by a final report in May 2009). The Study estimated that the undiscounted costs associated with implementing the preferred remedies would be approximately $10,219. On February 28, 2011, the DEC issued a Proposed Remedial Action Plan for the site and accepted public comments on the proposed remedy through March 29, 2011. We submitted comments to the DEC on this matter. In April 2011, the DEC issued the final Record of Decision (“ROD”) for the site. The ROD was subsequently rescinded by the DEC for failure to respond to all submitted comments. The preliminary ROD, however, estimated that the present cost associated with implementing the preferred remedies would be approximately $12,130. The DEC issued the final ROD in June 2011 with proposed remedies consistent with its earlier ROD. An Order on Consent and Administrative Settlement naming WSI and NiMo as Respondents was executed by the Respondents and DEC with an effective date of October 25, 2013. On January 29, 2016, a Cost-Sharing Agreement was executed between WSI, NiMo, Alcoa Inc. (“Alcoa”) and Reynolds Metal Company (“Reynolds”) whereby Alcoa and Reynolds elected to voluntarily participate in the onsite remediation activities at a combined 15% participant share. The majority of the remediation work was completed in fiscal year 2019. WSI is jointly and severally liable with NiMo, Alcoa and Reynolds for the total cost to remediate.

We have recorded an environmental remediation liability associated with the Potsdam site based on incurred costs to date and estimated costs to complete the remediation in other accrued liabilities and other long-term liabilities. Our expenditures could be significantly higher if costs exceed estimates. We inflate the estimated costs in current dollars to the expected time of payment and discount the total cost to present value using a risk-free interest rate of 1.5%.

A summary of the changes to the environmental remediation liability associated with the Potsdam site follows:


	Fiscal Year Ended December 31,
	2019		2018
Beginning balance	$	5,614	$	5,758

Obligations settled (1)	(4,463)		(171)
Obligations incurred	—		27

Ending balance	$	1,151	$	5,614

(1)Includes amounts that are being processed through accounts payable as a part of our disbursements cycle.

The total expected environmental remediation payments, in today’s dollars, for each of the five succeeding fiscal years and the aggregate amount thereafter are as follows:


Estimated Future Environmental Remediation Payments as of December 31, 2019
Fiscal year ending December 31, 2020	$	446
Fiscal year ending December 31, 2021	382
Fiscal year ending December 31, 2022	392
Fiscal year ending December 31, 2023	367
Fiscal year ending December 31, 2024	386
Thereafter	4,630
Total	$	6,603

A reconciliation of the expected aggregate non-inflated, undiscounted environmental remediation liability to the amount recognized in the statement of financial position is as follows:



Undiscounted liability	$	6,603
Less discount, net	(856)
Liability balance - December 31, 2019	$	5,747

Any substantial liability incurred by us arising from environmental damage could have a material adverse effect on our business, financial condition and results of operations. We are not presently aware of any other situations that would have a material adverse impact on our business, financial condition, results of operations or cash flows.

Legal Proceedings

North Country Environmental Services

On or about March 8, 2018, the Citizen Groups described above delivered correspondence to our subsidiary, North Country Environmental Services, Inc. ("NCES") and us, providing notice of the Citizen Groups' intent to sue NCES and us for violations of the CWA in conjunction with NCES's operation of its landfill in Bethlehem, New Hampshire ("NCES Landfill"). On May 14, 2018, the Citizen Groups filed a lawsuit against NCES and us in the United States District Court for the District of New Hampshire (the “New Hampshire Court”) alleging violations of the CWA, arguing that ground water discharging into the Ammonoosuc River is a "point source" under the CWA (the "New Hampshire Litigation"). The New Hampshire Litigation seeks remediation and fines under the CWA. On June 15, 2018, we and NCES filed a Motion to Dismiss the New Hampshire Litigation. On July 13, 2018, the Citizen Groups filed objections to our Motion to Dismiss. On July 27, 2018, we filed a reply in support of our Motion to Dismiss. On September 25, 2018, the New Hampshire Court denied our Motion to Dismiss. In March of 2019, we filed a motion in the New Hampshire Litigation asking for a stay of this litigation until certain appeals from discordant federal circuits were heard by the Supreme Court of the United States (“SCOTUS”). SCOTUS has granted certiorari determining that the circumstances described are sufficient for SCOTUS to hear such cases. Our motion for a stay was granted in the New Hampshire Litigation, and SCOTUS is expected to hear and rule on such cases this calendar year. In any event, we intend to continue to vigorously defend against the New Hampshire Litigation, which we believe is without merit.

Ontario County, New York Class Action Litigation

On or about September 17, 2019, Richard Vandemortel and Deb Vandemortel filed a class action complaint against us on behalf of similarly situated citizens in Ontario County, New York. The lawsuit has been filed in Ontario County (the “New York Litigation”). It alleges that over one thousand (1,000) citizens constitute the putative class in the New York Litigation, and it seeks damages for diminution of property values and infringement of the putative class’ rights to live without interference to their daily lives due to odors emanating from the Ontario County Landfill, which is operated by us pursuant to a long-term Operation, Maintenance and Lease Agreement with Ontario County. The New York Litigation was served on us on October 14, 2019. We are reviewing the New York Litigation and intend to present a vigorous defense.

Loss Contingency

On January 9, 2019, NCES filed an application for a 1.2 million (cy) expansion of the capacity of the NCES Landfill with the New Hampshire Department of Environmental Services (“NHDES”) (“Stage VI Expansion”). The Stage VI Expansion would provide NCES with over five (5) years of additional capacity beyond the capacity of Stage V.

In January 2020, NHDES informed NCES and us that NHDES had concerns regarding the short-term public benefit need for the Stage VI expansion, and also in respect of certain technical concerns regarding the Stage VI expansion. Given the fact the NHDES decided to review our permit application for the Stage VI Expansion with respect to public benefit determination using a different regulatory framework than used in any of our previous permitting activities at NCES, we informed the NHDES on February 11, 2020, that while we vigorously disagreed with NHDES’ review of our application and the context for the NHDES’ concerns, we would withdraw our application with the expectation of refiling the application with the NHDES as soon as possible. While the refiling of the application for the Stage VI Expansion could be rejected by the NHDES, and while delay of the Stage VI Expansion will surely occur, we remain confident that we will receive a permit for the Stage VI Expansion. We believe that a loss of $1,195 is reasonably possible, but not probable.

Employment Contracts

We have entered into employment contracts with five of our executive officers. The contracts are dated June 18, 2001, March 31, 2006, July 6, 2010, September 1, 2012 and March 1, 2016. Each contract had an initial term between one and three years and a covenant not-to-compete ranging from one to two years from the date of termination. These contracts automatically extend for a one year period at the end of the initial term and any renewal period. Total annual commitments for salaries under these contracts are $1,937. In the event of a change in control of us, or in the event of involuntary termination without cause, the employment contracts provide for a payment ranging from one to three years of salary and bonuses. We also have other employment contracts or arrangements with employees who are not executive officers.

STOCKHOLDERS' EQUITY

12 Months Ended

Dec. 31, 2019

Equity [Abstract]

STOCKHOLDERS' EQUITY

Public Offering of Class A Common Stock

In fiscal year 2019, we completed a public offering of 3,565 shares of our Class A common stock at a public offering price of $29.50 per share. The offering resulted in net proceeds to us of $100,446, after deducting underwriting discounts and commissions and offering expenses. The net proceeds from the offering were and are to be used for general corporate purposes, including potential acquisitions or development of new operations or assets with the goal of complementing or expanding our business, working capital and capital expenditures.

In fiscal year 2019, we completed the unregistered sale of 59 shares of our Class A common stock at a price of $44.15 per share. The sale resulted in net proceeds to us of $2,619. The shares were previously held in escrow according to the terms of our acquisition of WSI and released to us for liquidation to offset costs associated with the environmental remediation of the WSI's Potsdam, New York site. We recorded a $2,619 reduction of goodwill in line with business combination standards in place at the time the shares held in escrow were issued. See Note 12, Commitments and Contingencies for additional disclosure.

Common Stock

The holders of the Class A common stock are entitled to one vote for each share held. The holders of the Class B common stock are entitled to ten votes for each share held, except for the election of one director, who is elected by the holders of the Class A common stock exclusively. The Class B common stock is convertible into Class A common stock on a share-for-share basis at the option of the shareholder.

Preferred Stock

We are authorized to issue up to 944 shares of preferred stock in one or more series. As of December 31, 2019 and December 31, 2018, we had no shares issued.

Stock Based Compensation

Stock Incentive Plans

2006 Stock Incentive Plan. In the fiscal year ended April 30, 2007, we adopted the 2006 Stock Incentive Plan (“2006 Plan”). The 2006 Plan was amended in the fiscal year ended April 30, 2010. The 2006 Plan terminated as of October 9, 2016 and as a result no additional awards may be made pursuant to the 2006 Plan. Outstanding shares which are not actually issued under the 2006 Plan because such awards expire or otherwise result in shares not being issued are reserved for issuance under the 2016 Plan.

2016 Incentive Plan. In fiscal year 2016, we adopted the 2016 Incentive Plan (“2016 Plan”). Under the 2016 Plan, we may grant awards up to an aggregate amount of shares equal to the sum of: (i) 2,250 shares of Class A common stock (subject to adjustment in the event of stock splits and other similar events), plus (ii) such additional number of shares of Class A common stock (up to 2,723 shares) as is equal to the sum of the number of shares of Class A common stock that remained available for grant under the 2006 Plan immediately prior to the expiration of the 2006 Plan and the number of shares of Class A common stock subject to awards granted under the 2006 Plan that expire or otherwise result in shares not being issued.

As of December 31, 2019, there were 1,361 Class A common stock equivalents available for future grant under the 2016 Plan, inclusive of additional Class A common stock equivalents that were previously issued under terminated plans and have become available for grant because such awards expired or otherwise resulted in shares not being issued.

Our equity awards granted consist of stock options, including market-based performance stock options, restricted stock, restricted stock units and performance stock units, including market-based performance stock units.

Stock options are granted at a price equal to the prevailing fair value of our Class A common stock at the date of grant. Generally, stock options granted have a term not to exceed ten years and vest over a one year to four year period from the date of grant.

The fair value of each stock option granted, with the exception of market-based performance stock option grants, is estimated using a Black-Scholes option-pricing model, which requires extensive use of accounting judgment and financial estimation, including estimates of the expected term stock option holders will retain their vested stock options before exercising them and the estimated volatility of our Class A common stock price over the expected term. The fair value of each market-based performance stock option granted is estimated using a Monte Carlo option-pricing model, which also requires extensive use of accounting judgment and financial estimation, including estimates of the expected term stock option holders will retain their vested stock options before exercising them and the estimated volatility of our Class A common stock price over the expected term, but also including estimates of share price appreciation of our Class A common stock as compared to the Russell 2000 Index over the requisite service period.

Restricted stock, restricted stock units and performance stock units are granted at a price equal to the fair value of our Class A common stock at the date of grant. The fair value of each market-based performance stock unit is estimated using a Monte Carlo pricing model, which requires extensive use of accounting judgment and financial estimation, including the estimated share price appreciation plus the value of dividends of our Class A common stock as compared to the Russell 2000 Index over the requisite service period.

Restricted stock granted to non-employee directors vest incrementally over a three year period beginning on the first anniversary of the date of grant. Restricted stock units granted to non-employee directors vest in full on the first anniversary of the grant date. Restricted stock units vest incrementally over an identified service period beginning on the grant date based on continued employment. Performance stock units and market-based performance stock units vest at a future date following the grant date and are based on the attainment of performance targets and market achievements.

Stock Options

A summary of stock option activity is as follows:


	Stock Options	Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (years)	Aggregate Intrinsic Value
Outstanding, December 31, 2018	669	$	6.37
Granted	—	$	—
Exercised	(571)	$	5.88
Forfeited or expired	—	$	—

Outstanding, December 31, 2019	98	$	9.20	5.8	$	3,614
Exercisable, December 31, 2019	98	$	9.20	5.8	$	3,614

During fiscal years 2019, 2018 and 2017, stock-based compensation expense for stock options was $0, $473 and 644, respectively.

During fiscal years 2019, 2018 and 2017, the aggregate intrinsic value of stock options exercised was $19,475, $1,916 and $4,664, respectively.

As of December 31, 2019, there was no remaining unrecognized stock-based compensation expense related to outstanding stock options.

Our calculation of stock-based compensation expense associated with stock options granted, with the exception of market-based performance stock option grants which are valued using a Monte Carlo option-pricing model, was made using the Black-Scholes valuation model. We did not grant any new stock options in fiscal years 2019, 2018 or 2017.

Expected life is calculated based on the weighted average historical life of the vested stock options, giving consideration to vesting schedules and historical exercise patterns. Risk-free interest rate is based on the U.S. Treasury yield curve for the period of the expected life of the stock option. Expected volatility is calculated using the weekly historical volatility of our Class A common stock over the expected life, except in the case of market-based performance stock option where the daily historical volatility of our Class A common stock over the expected life is used.

The Black-Scholes valuation model and the Monte Carlo option-pricing model each require extensive use of accounting judgment and financial estimation. Application of alternative assumptions could produce significantly different estimates of the fair value of stock-based compensation and consequently, the related amounts recognized in the consolidated statements of operations.

Other Stock Awards

A summary of restricted stock, restricted stock unit and performance stock unit activity is as follows:


	Restricted Stock, Restricted Stock Units, and Performance Stock Units (1)	Weighted Average Grant Price		Weighted Average Remaining Contractual Term (years)	Aggregate Intrinsic Value
Outstanding, December 31, 2018	686	$	15.56
Granted	166	$	37.24
Class A common stock vested	(449)	$	12.38
Forfeited or canceled	(10)	$	23.41
Outstanding, December 31, 2019	393	$	28.23	1.3	$	6,992
Unvested, December 31, 2019	579	$	29.69	1.4	$	9,458

(1)Market-based performance stock unit grants are included at 100%. Attainment of maximum performance targets and market achievements would result in the issuance of an additional 186 shares of Class A common stock currently included in unvested. The market-based performance stock unit grants that vested in fiscal year 2019 resulted in the issuance of 178 additional shares of Class A common stock.

During fiscal years 2019, 2018 and 2017, stock-based compensation expense related to restricted stock, restricted stock units and performance stock units was $7,036, $7,821 and $5,652, respectively.

During fiscal years 2019, 2018 and 2017, the total fair value of other stock awards vested was $8,177, $10,529 and $5,706, respectively.

As of December 31, 2019, total unrecognized stock-based compensation expense related to restricted stock units was $3,156, which will be recognized over a weighted average period of 1.2 years. Total unrecognized stock-based compensation expense related to performance stock units, assuming the attainment of maximum performance targets, was $6,051, which will be recognized over a weighted average period of 1.5 years.

The weighted average fair value of market-based performance stock units granted during fiscal year 2019 was $38.74 per award, which was calculated using a Monte Carlo pricing model assuming a risk free interest rate of 2.28% and an expected volatility of 30.9% assuming no expected dividend yield. Risk-free interest rate is based on the U.S. Treasury yield curve for the expected service period of the award. Expected volatility is calculated using the daily volatility of our Class A common stock over the expected service period of the award.

The Monte Carlo pricing model requires extensive use of accounting judgment and financial estimation. Application of alternative assumptions could produce significantly different estimates of the fair value of stock-based compensation and consequently, the related amounts recognized in the consolidated statements of operations.

We also recorded $186, $150 and $136 of stock-based compensation expense related to our Amended and Restated 1997 Employee Stock Purchase Plan during fiscal years 2019, 2018 and 2017, respectively.

Tax (benefits) provisions for income taxes associated with stock-based compensation during fiscal years 2019, 2018 and 2017 of $(291), $(23) and $117, respectively.

Accumulated Other Comprehensive Income (Loss)

Accumulated other comprehensive income (loss) is a component of stockholders' equity (deficit) included in the accompanying consolidated balance sheets and includes, as applicable, the effective portion of changes in the fair value of our cash flow hedges and the changes in fair value of our marketable securities.

The changes in the balances of each component of accumulated other comprehensive income (loss) are as follows:


	Marketable Securities		Interest Rate Swaps		Total
Balance as of December 31, 2016	$	(68)	$	—	$	(68)

Other comprehensive income (loss) before reclassifications	59		(143)		(84)
Amounts reclassified from accumulated other comprehensive income (loss)	—		421		421
Income tax expense related to items in other comprehensive income (loss)	27		(112)		(85)
Other comprehensive income, net	86		166		252
Balance as of December 31, 2017	18		166		184
Cumulative effect of new accounting principle	(18)		—		(18)
Other comprehensive loss before reclassifications	—		(1,837)		(1,837)
Amounts reclassified from accumulated other comprehensive loss	—		363		363

Other comprehensive loss	—		(1,474)		(1,474)
Balance as of December 31, 2018	—		(1,308)		(1,308)

Other comprehensive loss before reclassifications	—		(5,286)		(5,286)
Amounts reclassified from accumulated other comprehensive loss	—		553		553

Other comprehensive loss	—		(4,733)		(4,733)
Balance as of December 31, 2019	$	—	$	(6,041)	$	(6,041)

A summary of reclassifications out of accumulated other comprehensive income (loss) for fiscal years 2019, 2018 and 2017 is as follows:


	Fiscal Year Ended December 31,
	2019		2018		2017
Details About Accumulated Other Comprehensive Income (Loss) Components	Amounts Reclassified Out of Accumulated Other Comprehensive Income (Loss)							Affected Line Item in the Consolidated Statements of Operations
Interest rate swaps	$	553	$	363	$	421	Interest expense
	553		363		421		Income (loss) before income taxes
	—		—		—		Benefit for income taxes
	$	553	$	363	$	421	Net income (loss)

FAIR VALUE OF FINANCIAL INSTRUMENTS

12 Months Ended

Dec. 31, 2019

Fair Value Disclosures [Abstract]

FAIR VALUE OF FINANCIAL INSTRUMENTS

We use a three-tier fair value hierarchy to classify and disclose all assets and liabilities measured at fair value on a recurring basis, as well as assets and liabilities measured at fair value on a non-recurring basis, in periods subsequent to their initial measurement. These tiers include: Level 1, defined as quoted market prices in active markets for identical assets or liabilities; Level 2, defined as inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; and Level 3, defined as unobservable inputs that are not corroborated by market data.

We use valuation techniques that maximize the use of market prices and observable inputs and minimize the use of unobservable inputs. In measuring the fair value of our financial assets and liabilities, we rely on market data or assumptions that we believe market participants would use in pricing an asset or a liability.

Assets and Liabilities Accounted for at Fair Value on a Recurring Basis

Our financial instruments include cash and cash equivalents, accounts receivable, restricted investment securities held in trust on deposit with various banks as collateral for our obligations relative to our landfill final capping, closure and post-closure costs, interest rate derivatives, trade payables and long-term debt. The carrying values of cash and cash equivalents, accounts receivable and trade payables approximate their respective fair values due to their short-term nature. The fair value of restricted investment securities held in trust, which are valued using quoted market prices, are included as restricted assets in the Level 1 tier below. The fair value of interest rate derivatives included in the Level 2 tier below is calculated using discounted cash flow valuation methodologies based upon the one month LIBOR yield curves that are observable at commonly quoted intervals for the full term of the swaps. We recognize all derivatives accounted for on the balance sheet at fair value. See Note 11, Debt for disclosure over the fair value of debt.

Recurring Fair Value Measurements

Summaries of our financial assets and liabilities that are measured at fair value on a recurring basis are as follows:


	Fair Value Measurement at December 31, 2019 Using:
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:



Restricted investment securities - landfill closure	$	1,586	$	—	$	—
Liabilities:
Interest rate swaps	$	—	$	5,427	$	—


	Fair Value Measurement at December 31, 2018 Using:
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:

Restricted investment securities - landfill closure	$	1,248	$	—	$	—
Interest rate swaps	—		820		—
	$	1,248	$	820	$	—
Liabilities:
Interest rate swaps	$	—	$	1,942	$	—

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

EMPLOYEE BENEFIT PLANS

12 Months Ended

Dec. 31, 2019

Retirement Benefits [Abstract]

EMPLOYEE BENEFIT PLANS

Defined Contribution Plan

We offer our eligible employees the opportunity to contribute to a 401(k) plan (“401(k) Plan”). Under the provisions of the 401(k) Plan participants may direct us to defer a portion of their compensation to the 401(k) Plan, subject to Internal Revenue Code limitations. We provide an employer matching contribution equal to fifty cents for every dollar an employee invests in the 401(k) Plan up to our maximum match of one thousand dollars per employee per calendar year, subject to revision. Participants vest in employer contributions ratable over a three year period. Employer contributions for fiscal years 2019, 2018 and 2017 amounted to $1,608, $1,319 and $1,817, respectively.

Employee Stock Purchase Plan

We offer our eligible employees the opportunity to participate in an employee stock purchase plan. Under this plan, qualified employees may purchase shares of Class A common stock by payroll deduction at a 15% discount from the market price. During fiscal years 2019, 2018 and 2017, 23, 26 and 41 shares, respectively, of Class A common stock were issued under this plan. As of December 31, 2019, 94 shares of Class A common stock were available for distribution under this plan.

Multiemployer Pension Plan

We make contributions to a multiemployer defined benefit pension plan, the New England Teamsters and Trucking Industry Pension Fund (the “Pension Plan”), under the terms of a collective bargaining agreement (“CBA”) that covers certain of our union represented employees. The Pension Plan provides retirement benefits to participants based on their service to contributing employers. We do not administer the Pension Plan. The risks of participating in a multiemployer pension plan are different from a single-employer pension plan in that: (i) assets contributed to the multiemployer pension plan by one employer may be used to provide benefits to employees or former employees of other participating employers; (ii) if a participating employer stops contributing to the plan, the unfunded obligations of the plan may be required to be assumed by the remaining participating employers; and (iii) if we choose to stop participating in our multiemployer Pension Plan, we may be required to pay the plan a withdrawal amount based on the underfunded status of the plan.

In October 2019, we reached an agreement to withdraw from the Pension Plan by entering into Withdrawal and Re-entry Agreements with the Pension Plan. In accordance with FASB ASC 450 - Contingencies, because of our withdrawal from the Pension Plan, we recorded an obligation of $3,194 as of September 30, 2019 and a charge of $3,591 as pension withdrawal expense, offset by a $397 retroactive contribution credit recorded as cost of operations, in fiscal year 2019. While the withdrawal generates a fixed yearly contingent liability for us for a period of approximately seventeen (17) years, it caps our gross payments at $4,224 significantly reducing our cash exposure from the potential $18,511 withdrawal liability as determined based on a complete withdrawal. As per the Re-entry Agreements and upon withdrawal, we re-entered the Pension Plan with certainty from a liability perspective. We have not, however, changed the terms of our CBA with Local 170, which remains in effect until June 30, 2020. As of December 31, 2019, we had a remaining obligation of $1,838 associated with our withdrawal.

The following table outlines the status of the Pension Plan:


Pension Fund	EIN/Pension Plan Number	Pension Protection Act Zone Status			Funding Improvement or Rehabilitation Plan Status		Contributions to Plan								Expiration Date of CBA
													Fiscal Year Ended December 31,
			2019	2018					2019			2018		2017
New England Teamsters and Trucking Industry Pension Fund	04-6372430	Critical and declining	Critical and declining	Implemented	$	409	$	726		$	627		June 30, 2020

The status is based on the latest plan information for the plan year ended September 30, 2019 that we received from the Pension Plan and is certified by the Pension Plans’ actuary. Plans with a “critical and declining” status are funded at less than 65%, have a projected funding deficiency in the current or next four plan years and have a projected insolvency date which is less than the 20-year minimum statutory requirement. Our contributions to the Pension Plan represent less than 5% of total contributions to such plan for the plan year ended September 30, 2018 and a rehabilitation plan has been implemented with no surcharge imposed. Under current law regarding multiemployer benefit plans, a plan’s termination, our voluntary withdrawal, or the withdrawal of all contributing employers from any under-funded multiemployer pension plan would require us to make payments to the plan for our proportionate share of the multiemployer plan’s unfunded vested liabilities. We could have adjustments to estimates for these matters in the near term that could have a material effect on its consolidated financial position, results of operations or cash flows. At the date these financial statements were issued, a Form 5500 was not available for the plan year ended September 30, 2019.

INCOME TAXES

12 Months Ended

Dec. 31, 2019

Income Tax Disclosure [Abstract]

INCOME TAXES

A summary of the benefit for income taxes is as follows:


	Fiscal Year Ended December 31,
	2019		2018		2017
Federal
Current	$	(951)	$	(1,902)	$	—

Deferred	(699)		1,255		(15,614)
	(1,650)		(647)		(15,614)
State
Current	321		2,575		301
Current benefit of loss carryforwards	—		(2,307)		(28)
Deferred	(545)		(5)		88
	(224)		263		361
Benefit for income taxes	$	(1,874)	$	(384)	$	(15,253)

During fiscal years 2019 and 2018, we recognized a $(2,385) and $(937) deferred tax benefit, respectively, due to a reduction of the valuation allowance on acquisitions. In determining the need for a valuation allowance, we have assessed the available means of recovering deferred tax assets, including the existence of reversing temporary differences. The valuation allowance decreased due to the recognition of additional reversing temporary differences from the $2,385 and $937 deferred tax liability recorded through goodwill on the acquisition of a company in May 2019 and the acquisition of two companies in January 2018, respectively. The deferred tax liabilities related to the acquisitions were based on the impact of temporary differences between the amounts of assets and liabilities recognized for financial reporting purposes and such amounts recognized for income tax purposes. The valuation allowance was reduced by $(2,137) and $(1,635) in the quarters ended June 30, 2019 and March 31, 2018, respectively, with the offsetting increase in the goodwill, based on initial estimates of the acquired temporary differences. The valuation allowance was decreased by $(248) in the quarter ended December 31, 2019 and increased by $698 in subsequent quarters of fiscal year 2018, with an offsetting adjustment to goodwill, based on the availability of better estimates upon the filing of the prior year returns by the sellers.

During 2019, we recognized a $(297) deferred tax benefit due to a reduction of the deferred tax liability related to indefinite lived assets. The financial statement value of indefinite lived goodwill was reduced as a result of a settlement of an acquisition contingency that pre-dated the effective date of ASC 805, which resulted in a reduction of the related deferred tax liability.

On December 22, 2017, the Tax Cuts and Jobs Act was enacted. The Tax Cuts and Jobs Act, which is also commonly referred to as “U.S. tax reform,” significantly changes United States corporate income tax laws by, among other things, reducing the US corporate income tax rate from 35% to 21% starting in 2018. Under the Tax Cuts and Jobs Act, federal net operating loss carryforwards generated as of the end of 2017 continue to be carried forward for 20 years and are generally available to fully offset taxable income earned in a tax year. Federal net operating losses generated after 2017 will be carried forward indefinitely, but generally may only offset up to 80% of taxable income earned in future tax years. In fiscal year 2017, we revalued our deferred taxes due to these changes, including (a) revaluing our federal net deferred taxes before valuation allowance using the 21% tax rate resulting in an increased net federal deferred tax provision of $33,700; (b) revaluing our federal valuation allowance using the 21% tax rate, including the impact of tax planning strategies, resulting in a federal deferred tax benefit to continuing operations of $(36,556); and (c) recognizing a federal deferred tax benefit of $(12,758) for 80% of indefinite lived deferred tax liabilities, which are anticipated to be available as a source of taxable income upon reversal of deferred tax assets that would also have indefinite lives.

The differences in the benefit for income taxes and the amounts determined by applying the Federal statutory rate to income before provision for income taxes are as follows:


	Fiscal Year Ended December 31,
	2019			2018			2017
Federal statutory rate	21		%	21		%	35		%
Tax at statutory rate	$	6,254		$	1,268		$	(12,968)
State income taxes, net of federal benefit	(161)			(89)			(1,959)
Decrease in net federal deferred tax assets before valuation allowance change due to federal rate change	—			—			33,700
Decrease in valuation allowance by 80% of indefinite lived deferred liabilities due to US tax reform	—			—			(12,758)
Other changes in valuation allowance, including the federal rate change in fiscal year 2017	(978)			(1,613)			(18,848)
Deductible stock awards	(7,235)			(2,048)			(1,825)
Non-deductible expenses	638			633			542
Non-deductible officer compensation	314			2,214			—

Tax credits	(82)			(686)			(1,000)



Other, net	(624)			(63)			(137)
Benefit for income taxes	$	(1,874)		$	(384)		$	(15,253)

Deferred income taxes reflect the impact of temporary differences between the amounts of assets and liabilities recognized for financial reporting purposes and such amounts recognized for income tax purposes. A summary of deferred tax assets and liabilities is as follows:


	December 31,
	2019		2018
Deferred tax assets:
Net operating loss carryforwards	$	45,900	$	31,241
Accrued expenses and reserves	36,342		34,647
General business tax credit carryforwards	6,273		6,192
Book over tax depreciation of property and equipment	2,882		19,048
Unrealized loss on hedges and swaps	1,768		—
Stock awards	1,746		2,310
Alternative minimum tax credit carryforwards	951		1,902

Other	2,576		3,023
Total deferred tax assets	98,438		98,363
Less: valuation allowance	(69,402)		(69,189)
Total deferred tax assets after valuation allowance	29,036		29,174
Deferred tax liabilities:
Amortization of intangibles	(22,910)		(22,026)
Other	(192)		(73)
Total deferred tax liabilities	(23,102)		(22,099)
Net deferred tax asset	$	5,934	$	7,075

The net deferred tax asset at December 31, 2019 is reflected on the balance sheet as a long-term deferred federal tax asset of $8,577 and a long-term deferred state tax liability of $(2,643).

As of December 31, 2019, we have, for federal income tax purposes, net operating loss carryforwards of approximately $110,587 that expire in the fiscal years ending December 31, 2031 through 2037 and $67,399, which do not expire. We have state net operating loss carryforwards of approximately $101,628 that expire in the fiscal years ending December 31, 2020 through 2039. In addition, we have $951 minimum tax credit carryforwards which are fully refundable for tax years 2020 through 2021, if not otherwise used to offset tax liabilities. We also have $6,273 general business credit carryforwards which expire in the fiscal years ending December 31, 2022 through 2039. Sections 382 and 383 of the Internal Revenue Code can limit the amount of net operating loss and credit carryforwards which may be used in a tax year in the event of certain stock ownership changes. With the exception of $1,756 federal net operating losses we acquired through acquisitions, we are not currently subject to these limitations but could become subject to them if there were significant changes in the ownership of our stock.

In assessing the realizability of carryforwards and other deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. We adjust the valuation allowance in the period management determines it is more likely than not that deferred tax assets will or will not be realized. The change in the valuation allowance was an increase of $213 and $834 from fiscal years 2019 and 2018, respectively. In determining the need for a valuation allowance, we have assessed the available means of recovering deferred tax assets, including the ability to carryback net operating losses, the existence of reversing temporary differences, and available sources of future taxable income. We have also considered the ability to implement certain strategies, such as a potential sale of assets that would, if necessary, be implemented to accelerate taxable income and use expiring deferred tax assets.

The net deferred tax assets include deferred tax liabilities related to amortizable goodwill, which are anticipated to reverse in an indefinite future period and to generate future taxable income upon reversal. Prior to the Tax Cuts and Jobs Act, federal net operating losses, including potential losses from the reversal of deferred tax assets, could only be carried forward for 20 years. The reversal of the indefinite lived goodwill was not available as a source of future taxable income since it was uncertain whether the income generated would be available in the same tax periods in which losses from the reversal of deferred tax assets could be utilized. As such, prior to the Tax Cuts and Jobs Act we did not treat the reversal of amortizable goodwill as an available source of taxable income in determining the valuation allowance.

Beginning in 2018 under the Tax Cuts and Jobs Act, future federal net operating losses generated may be carried forward indefinitely and generally may offset up to 80% of taxable income earned in a tax year. Because potential losses from the reversal of deferred tax assets in future years may be carried forward indefinitely, we consider it more likely than not that 80% of the reversal of deferred tax liabilities for amortizable goodwill will be available as a source of taxable income.

In the fourth quarter of 2017, we revalued our net federal deferred tax assets using the 21% tax rate as enacted under the Tax Cuts and Jobs Act. The valuation allowance was also adjusted in this quarter due to the federal tax rate change and to recognize a $(12,758) federal deferred tax benefit for 80% of deferred tax liabilities for amortizable goodwill. Due to the Tax Cuts and Jobs Act, we recognized a $(15,614) federal deferred tax benefit in 2017 and decreased our total valuation allowance by $(29,234). We believe we are able to support the deferred tax assets recognized as of the end of fiscal years 2019 and 2018 based on all of the available evidence.

The provisions of FASB ASC 740-10-25-5 prescribe the minimum recognition threshold that a tax position is required to meet before being recognized in the financial statements. Additionally, FASB ASC 740-10-25-5 provides guidance on de-recognition, measurement, classification, interest and penalties, accounting in interim periods, disclosure and transition. Under FASB ASC 740-10-25-5, an entity may only recognize or continue to recognize tax positions that meet a “more likely than not” threshold.

A reconciliation of the beginning and ending amount of gross unrecognized tax benefits is as follows:


	Fiscal Year Ended December 31,
	2019		2018
Unrecognized tax benefits at beginning of period	$	2	$	1,941


Reductions resulting from lapse of statute of limitations	(1)		(1,939)


Unrecognized tax benefits at end of period	$	1	$	2

The fiscal year 2018 reductions resulting from a lapse of the statute of limitations primarily related to unrecognized benefits which had reduced net operating loss carryforwards. The tax positions primarily related to fiscal years 2007 and prior and, based on administrative practice of the tax authorities, we have reduced the unrecognized tax benefits.

Included in the balances at December 31, 2019 and December 31, 2018 are $1 and $2, respectively, of unrecognized tax benefits (net of the federal benefit on state issues) that, if recognized, would favorably affect the effective income tax rate in future periods. We anticipate $0 of unrecognized tax benefits to reverse within the next 12 months due to the expiration of the applicable statute of limitations.

Our continuing practice is to recognize interest and penalties related to income tax matters in income tax expense. Related to uncertain tax positions during fiscal years 2019, 2018 and 2017, we have accrued interest of $1, $2 and $3 and penalties of $1, $1 and $2, respectively. We accrued $(1), $(2) and $(3) for interest and penalties in income tax expense related to uncertain tax positions during fiscal years 2019, 2018 and 2017, respectively.

To the extent interest and penalties are not assessed with respect to uncertain tax positions, amounts accrued will be reduced and reflected as a reduction of the overall income tax provision.

We are subject to U.S. federal income tax, as well as income tax of multiple state jurisdictions. Due to Federal and state net operating loss carryforwards, income tax returns from years ending in 1998 through 2019 remain open for examination, with limited exceptions.

OTHER ITEMS AND CHARGES

12 Months Ended

Dec. 31, 2019

Unusual or Infrequent Items, or Both [Abstract]

OTHER ITEMS AND CHARGES

Southbridge Landfill Closure Charge, Net

In June 2017, we initiated the plan to cease operations of our Southbridge Landfill and later closed it in November 2018 when Southbridge Landfill reached its final capacity. Accordingly, in fiscal years 2019, 2018 and 2017, we recorded charges associated with the closure of our Southbridge Landfill as follows:


	Fiscal Year Ended December 31,
	2019		2018		2017
Asset impairment charge (1)	$	—	$	—	$	47,999
Project development charge (2)	—		—		9,149
Environmental remediation charge (3)	—		—		6,379
Contract settlement charge (4)	—		8,724		—
Landfill closure project charge (5)	—		6,012		—
Charlton settlement charge (6)	—		1,216		—
Legal and transaction costs (7)	2,709		2,102		1,656
Recovery on insurance settlement (8)	—		(10,000)		—
Southbridge Landfill closure charge, net	$	2,709	$	8,054	$	65,183

(1)We performed a test of recoverability under FASB ASC 360, which indicated that the carrying value of our asset group that includes the Southbridge Landfill was no longer recoverable and, as a result, the asset group was assessed for impairment with an impairment charge allocated to the long-lived assets of the Southbridge Landfill in accordance with FASB ASC 360.

(2)We wrote-off deferred costs associated with Southbridge Landfill permitting activities no longer deemed viable.

(3)We recorded an environmental remediation charge associated with the installation of a municipal waterline.

(4)We recorded a contract settlement charge associated with the closure of Southbridge Landfill and the remaining future obligations due to the Town of Southbridge under the landfill operating agreement with the Town of Southbridge.

(5)We recorded a landfill closure project charge associated with increased costs under the revised closure plan at our Southbridge Landfill.

(6)We established a reserve associated with settlement of the Town of Charlton's claim against us.

(7)We incurred legal costs as well as other costs associated with various matters as part of the Southbridge Landfill closure.

(8)We recorded a recovery on an environmental insurance settlement associated with the Southbridge Landfill closure.

Expense from Acquisition Activities and Other Items

In fiscal year 2019, we recorded a charge of $2,687 associated primarily with acquisition activities. In fiscal year 2018, we recorded a charge of $1,872 associated with acquisition activities and the write-off of deferred costs related to the expiration of our shelf registration statement, and in fiscal year 2017, we recorded a charge of $176 associated with acquisition activities. See Note 5, Business Combinations for disclosure over acquisition activity.

Contract Settlement Charge

In fiscal year 2018, we recorded contract settlement charges of $2,100 associated with the termination and discounted buy-out of a commodities marketing and brokerage agreement.

Development Project Charge

In fiscal year 2018, we recorded a development project charge of $311 associated with previously deferred costs that were written off as a result of the negative vote in a public referendum relating to the NCES Landfill.

EARNINGS PER SHARE

12 Months Ended

Dec. 31, 2019

Earnings Per Share [Abstract]

EARNINGS PER SHARE

A summary of the numerator and denominators used in the computation of earnings per share is as follows:


	Fiscal Year Ended December 31,
	2019		2018		2017
Numerator:
Net income (loss)	$	31,653	$	6,420	$	(21,799)
Denominator:
Class A common stock	46,803		41,944		41,298
Class B common stock	988		988		988
Shares to be issued - acquisition	36		103		—
Unvested restricted stock	—		(9)		(38)
Effect of weighted average shares outstanding	(601)		(338)		(402)
Basic weighted average common shares outstanding	47,226		42,688		41,846
Impact of potentially dilutive securities:
Dilutive effect of stock options and stock awards	740		1,480		—
Diluted weighted average common shares outstanding	47,966		44,168		41,846
Antidilutive potentially issuable shares	2		2		2,219

RELATED PARTY TRANSACTIONS	12 Months Ended
RELATED PARTY TRANSACTIONS	Dec. 31, 2019
Related Party Transactions [Abstract]
RELATED PARTY TRANSACTIONS	RELATED PARTY TRANSACTIONS Services During fiscal years 2019, 2018 and 2017, we retained the services of Casella Construction, Inc. ("CCI"), a company substantially owned by sons of John Casella, our Chairman and Chief Executive Officer, and Douglas Casella, a member of our Board of Directors, as a contractor in developing or closing certain landfills owned by us as well as providing transportation services. Total purchased services charged to operations or capitalized to landfills for fiscal years 2019, 2018 and 2017 were $7,990, $3,442 and $3,398, respectively, of which $851 and $32 were outstanding and included in either accounts payable or other current liabilities as of December 31, 2019 and December 31, 2018, respectively. In addition to the total purchased services, we provided various waste collection and disposal services to CCI. Total revenues recorded for fiscal years 2019, 2018 and 2017 were $132, $156 and $237, respectively. Leases In the fiscal year ended April 30, 1994, we entered into two leases for operating facilities with a partnership of which John Casella, our Chairman and Chief Executive Officer, and Douglas Casella, a member of our Board of Directors, are the general partners. The leases have since been extended through August 2023. The terms of the lease agreements require monthly payments of approximately $29. Total expense charged to operations for fiscal years 2019, 2018 and 2017 under these agreements was $339, $349 and $360, respectively. Landfill Post-closure We have agreed to pay the cost of post-closure on a landfill owned by John Casella, our Chairman and Chief Executive Officer, and Douglas Casella, a member of our Board of Directors. We paid the cost of closing this landfill in 1992, and the post-closure maintenance obligations are expected to last until the fiscal year ending December 31, 2024. In fiscal years 2019, 2018 and 2017, we paid $9, $14 and $27, respectively, pursuant to this agreement. As of December 31, 2019 and December 31, 2018, we have accrued $37 and $48, respectively, for costs associated with its post-closure obligations.

SEGMENT REPORTING

12 Months Ended

Dec. 31, 2019

Segment Reporting [Abstract]

SEGMENT REPORTING

We report selected information about operating segments in a manner consistent with that used for internal management reporting. We classify our solid waste operations on a geographic basis through regional operating segments, our Western and Eastern regions. Revenues associated with our solid waste operations are derived mainly from solid waste collection and disposal, landfill, landfill gas-to-energy, transfer and recycling services in the northeastern United States. Our revenues in the Recycling segment are derived from municipalities and customers in the form of processing fees, tipping fees and commodity sales. Organics services, ancillary operations, along with major account and industrial services, are included in our Other segment. Effective January 1, 2020, we reorganized our operating segments as follows: we aligned our organics services and our major account and industrial services, with our Recycling segment to form the Resource Solutions segment, thus creating a single resource renewal-focused segment. We also moved our ancillary transportation services, which were previously included in our Other segment, into our Western region. Accordingly, as of January 1, 2020, our operating segments consist of the Eastern and Western regions and Resource Solutions.

Fiscal Year Ended December 31, 2019


Segment	Outside revenues		Inter-company revenue		Depreciation and amortization		Operating income (loss)		Interest expense, net		Capital expenditures		Goodwill		Total assets
Eastern	$	219,475	$	54,738	$	24,322	$	9,503	$	218	$	24,499	$	30,720	$	207,060
Western	343,399		97,339		47,666		41,883		63		63,540		141,054		598,910
Recycling	42,820		9,400		4,009		(814)		160		9,719		12,316		56,688
Other	137,596		2,443		3,793		2,503		24,294		5,407		1,729		69,524
Eliminations	—		(163,920)		—		—		—		—		—		—
Total	$	743,290	$	—	$	79,790	$	53,075	$	24,735	$	103,165	$	185,819	$	932,182

Fiscal Year Ended December 31, 2018


Segment	Outside revenues		Inter-company revenue		Depreciation and amortization		Operating income (loss)		Interest expense, net		Capital expenditures		Goodwill		Total assets
Eastern	$	206,473	$	52,866	$	26,538	$	4,684	$	12	$	23,393	$	28,154	$	184,679
Western	286,262		81,515		35,843		41,529		(148)		41,850		120,536		428,934
Recycling	42,191		6,426		4,345		(7,805)		140		4,476		12,315		48,629
Other	125,734		1,982		3,782		1,325		26,017		3,513		1,729		70,168
Eliminations	—		(142,789)		—		—		—		—		—		—
Total	$	660,660	$	—	$	70,508	$	39,733	$	26,021	$	73,232	$	162,734	$	732,410

Fiscal Year Ended December 31, 2017


Segment	Outside revenues		Inter-company revenue		Depreciation and amortization		Operating income (loss)		Interest expense, net		Capital expenditures		Goodwill		Total assets
Eastern	$	181,170	$	50,335	$	23,815	$	(51,867)	$	3	$	17,153	$	19,192	$	157,248
Western	250,771		71,510		30,766		35,035		(220)		42,082		89,369		344,324
Recycling	62,307		246		4,125		2,805		143		2,006		12,315		48,612
Other	105,061		1,881		3,396		1,444		24,961		3,621		1,729		64,765
Eliminations	—		(123,972)		—		—		—		—		—		—
Total	$	599,309	$	—	$	62,102	$	(12,583)	$	24,887	$	64,862	$	122,605	$	614,949

Amount of our total revenue attributable to services provided are as follows:


	Fiscal Year Ended December 31,
	2019						2018						2017
Collection	$	372,041	50.1	%	$	303,418	45.9	%	$	263,688	44.0	%
Disposal	181,895		24.5	%	181,110		27.4	%	160,073		26.7	%
Power generation	3,576		0.5	%	5,129		0.8	%	5,375		0.9	%
Processing	7,175		0.9	%	7,174		1.1	%	7,994		1.3	%
Solid waste operations	564,687		76.0	%	496,831		75.2	%	437,130		72.9	%
Organics	56,326		7.5	%	54,174		8.2	%	39,815		6.6	%
Customer solutions	79,457		10.7	%	67,464		10.2	%	60,057		10.1	%
Recycling	42,820		5.8	%	42,191		6.4	%	62,307		10.4	%
Total revenues	$	743,290	100.0	%	$	660,660	100.0	%	$	599,309	100.0	%

QUARTERLY FINANCIAL INFORMATION (UNAUDITED)

12 Months Ended

Dec. 31, 2019

Quarterly Financial Information Disclosure [Abstract]

QUARTERLY FINANCIAL INFORMATION (UNAUDITED)

The following is a summary of certain items in the consolidated statements of operations by quarter:


Fiscal Year 2019	First Quarter		Second Quarter		Third Quarter		Fourth Quarter
Revenues	$	163,664	$	187,459	$	198,547	$	193,619
Operating income	$	4,442	$	15,544	$	18,485	$	14,604
Net (loss) income	$	(1,714)	$	11,915	$	12,386	$	9,066

Earnings per common share:
Basic weighted average common shares outstanding	45,913		47,464		47,690		47,811
Basic earnings per share	$	(0.04)	$	0.25	$	0.26	$	0.19
Diluted weighted average common shares outstanding	42,913		48,221		48,361		48,583
Diluted earnings per share	$	(0.04)	$	0.25	$	0.26	$	0.19


Fiscal Year 2018	First Quarter		Second Quarter		Third Quarter		Fourth Quarter
Revenues	$	147,455	$	165,649	$	172,832	$	174,724
Operating income (loss)	$	838	$	15,149	$	28,884	$	(5,138)
Net (loss) income	$	(3,910)	$	1,704	$	22,302	$	(13,676)

Earnings per common share:
Basic weighted average common shares outstanding	42,370		42,661		42,779		42,936
Basic earnings per share	$	(0.09)	$	0.04	$	0.52	$	(0.32)
Diluted weighted average common shares outstanding	42,370		43,916		44,175		42,936
Diluted earnings per share	$	(0.09)	$	0.04	$	0.50	$	(0.32)

Our transfer and disposal revenues historically have been lower from the months of November through March. This seasonality reflects the lower volume of waste during the late fall, winter and early spring months. Since certain of our operating and fixed costs remain constant throughout fiscal year, operating income is impacted by a similar seasonality. In addition, particularly harsh weather conditions typically result in increased operating costs.

Our recycling business experiences increased volumes of newspaper in November and December due to increased retail activity during the holiday season.

Schedule II - Valuation Accounts

12 Months Ended

Dec. 31, 2019

SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]

Schedule II - Valuation Accounts

Schedule II

Valuation Accounts

Allowance for Doubtful Accounts

(in thousands)


	Fiscal Year Ended December 31,
			2019			2018			2017
Balance at beginning of period	$	931		$	809		$	1,069
Additions—charged to expense	1,360			1,620			290
Deductions—bad debts written off, net of recoveries	(823)			(1,498)			(550)
Balance at end of period	$	1,468		$	931		$	809

ACCOUNTING CHANGES (Policies)

12 Months Ended

Dec. 31, 2019

Accounting Changes and Error Corrections [Abstract]

Basis of Accounting

Casella Waste Systems, Inc. (“Parent”), its consolidated subsidiaries and any partially owned entities over which it has a controlling financial interest (collectively, “we”, “us” or “our”), is a regional, vertically integrated solid waste services company that provides collection, transfer, disposal, landfill, landfill gas-to-energy, recycling and organics services in the northeastern United States. We market recyclable metals, aluminum, plastics, paper and corrugated cardboard, which have been processed at our recycling facilities, as well as recyclables purchased from third-parties. We manage our solid waste operations on a geographic basis through two regional operating segments, our Eastern and Western regions, each of which provides a full range of solid waste services, and our larger-scale recycling and commodity brokerage operations through our Recycling segment. Organics services, ancillary operations, along with major account and industrial services are included in our Other segment. Effective January 1, 2020, we reorganized our operating segments as follows: we aligned our organics services and our major account and industrial services, with our Recycling segment to form the Resource Solutions segment, thus creating a single resource renewal-focused segment. We also moved our ancillary transportation services, which were previously included in our Other segment, into our Western region. Accordingly, as of January 1, 2020, our operating segments consist of the Eastern and Western regions and Resource Solutions.

The accompanying consolidated financial statements, which include the accounts of the Parent, our wholly-owned subsidiaries and any partially owned entities over which we have a controlling financial interest, have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). All significant intercompany accounts and transactions are eliminated in consolidation. Investments in entities in which we do not have a controlling financial interest are accounted for under either the equity method or the cost method of accounting, as appropriate.

Accounting Standards that are Adopted and Pending Adoption

Standard

Description

Effect on the Financial Statements or Other
Significant Matters

Accounting standards adopted effective January 1, 2019

ASU No. 2016-02, as amended through March 2019: Leases (Topic 842)

Standard

Description

Effect on the Financial Statements or Other
Significant Matters

Accounting standards issued pending adoption

ASU No. 2019-12: Income Taxes (Topic 740)

Reduces the complexity over accounting for income taxes by removing certain exceptions and amending guidance to improve consistent application of accounting over income taxes.

ASU No. 2017-04: Intangibles - Goodwill and Other (Topic 350)

ASU No. 2016-13: Financial Instrument Credit Losses (Topic 326)

Requires that an entity measures all of its expected credit losses for financial assets held based on historical experience, current conditions, and reasonable and supportable forecasts.

Management's Estimates and Assumptions

Management’s Estimates and Assumptions

Cash and Cash Equivalents

We consider all highly liquid investments purchased with original maturities of three months or less to be cash equivalents.

Concentrations of Credit Risk

Accounts Receivable, Net of Allowance for Doubtful Accounts

Accounts Receivable, Net of Allowance for Doubtful AccountsAccounts receivable represent receivables from customers for collection, transfer, recycling, disposal and other services. Our accounts receivable are recorded when billed or when related revenue is earned, if earlier, and represent claims against third-parties that will be settled in cash. The carrying value of our accounts receivable, net of allowance for doubtful accounts represents its estimated net realizable value. Estimates are used in determining our allowance for doubtful accounts based on our historical collection experience, current economic conditions and trends, credit policy and a review of our accounts receivable by aging category. Our reserve is evaluated and revised on a monthly basis. Past due accounts receivable are written off when deemed to be uncollectible.

Inventory

InventoryInventory includes secondary fibers, recyclables ready for sale, and parts and supplies. Inventory is stated at the lower of cost (first-in, first-out) or market.

Property, Plant and Equipment


Asset Classification						Estimated Useful Life
Buildings and improvements						10-30 years
Machinery and equipment						5-10 years
Rolling stock						5-10 years
Containers						5-12 years
Furniture and Fixtures						3-8 years

The cost of maintenance and repairs is charged to operations as incurred.

Landfill Accounting

Life Cycle Accounting

Landfill Development Costs

Landfill Airspace

We apply the following guidelines in determining a landfill’s remaining permitted and expansion airspace:

•we control the land on which the expansion is sought;

•all technical siting criteria have been met or a variance has been obtained or is reasonably expected to be obtained;

•we have not identified any legal or political impediments which we believe will not be resolved in our favor;

•we are actively working on obtaining any necessary permits and we expect that all required permits will be received; and

•senior management has approved the project based on a review of the engineering design and determination that the financial return profile meets our investment criteria.

Final Capping, Closure and Post-Closure Costs

The following is a description of our landfill asset retirement activities and related accounting:

See Note 10, Final Capping, Closure and Post-Closure Costs for disclosure over asset retirement obligations related to final capping, closure and post-closure costs.

Lease Accounting

Goodwill and Intangible Assets

See Note 9, Goodwill and Intangible Assets for disclosure over goodwill.

Investments in Unconsolidated Entities

Fair Value of Financial Instruments

Fair Value of Financial InstrumentsOur financial instruments may include cash and cash equivalents, accounts receivable, restricted investment securities held in trust on deposit with various banks as collateral for our obligations relative to our landfill final capping, closure and post-closure costs, restricted cash reserved to finance certain capital projects, interest rate derivatives, trade payables and long-term debt. Accounting standards include disclosure requirements around fair values used for certain financial instruments and establish a fair value hierarchy. The three-tier hierarchy prioritizes valuation inputs into three levels based on the extent to which inputs used in measuring fair value are observable in the market. Each fair value measurement is reported in one of three levels: Level 1, defined as quoted market prices in active markets for identical assets or liabilities; Level 2, defined as inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; and Level 3, defined as unobservable inputs that are not corroborated by market data.

Business Combinations

Environmental Remediation Liabilities

Self-Insurance Liabilities and Related Costs

Self-Insurance Liabilities and Related CostsWe are self-insured for vehicles and workers’ compensation with reinsurance coverage limiting our maximum exposure. Our maximum exposure in fiscal year 2019 under the workers’ compensation plan was $1,250 per individual event. Our maximum exposure in fiscal year 2019 under the automobile plan was $1,200 per individual event. The liability for unpaid claims and associated expenses, including incurred but not reported losses, is determined by management with the assistance of a third-party actuary and reflected in our consolidated balance sheet as an accrued liability. We use a third-party to track and evaluate actual claims experience for consistency with the data used in the annual actuarial valuation. The actuarial-determined liability is calculated based on historical data, which considers both the frequency and settlement amount of claims.

Income Taxes

Derivatives and Hedging

Contingent Liabilities and Legal Proceedings

Contingent Liabilities

Revenue Recognition

Asset Impairments

•a significant decrease in the market price of an asset or asset group;

•a significant adverse change in the extent or manner in which an asset or asset group is being used or in its physical condition;

•a significant adverse change in legal factors or in the business climate that could affect the value of an asset or asset group, including an adverse action or assessment by a regulator;

•an accumulation of costs significantly in excess of the amount originally expected for the acquisition or construction of a long-lived asset;

•a current expectation that, more likely than not, a long-lived asset or asset group will be sold or otherwise disposed of significantly before the end of its previously estimated useful life; or

•an impairment of goodwill at a reporting unit.

See Note 17, Other Items and Charges for disclosure related to long-lived asset impairments recognized during the reporting periods.

Goodwill. We annually assess goodwill for impairment at the end of our fiscal year or more frequently if events or circumstances indicate that impairment may exist.

•a significant adverse change in legal status or in the business climate;

•an adverse action or assessment by a regulator;

•a more likely than not expectation that a segment or a significant portion thereof will be sold; or

•the testing for recoverability of a significant asset group within the segment.

Defined Benefit Pension Plan

Defined Benefit Pension Plan We make contributions to one qualified multiemployer defined benefit pension plan, the New England Teamsters and Trucking Industry Pension Fund ("Pension Plan"). The Pension Plan provides retirement benefits to participants based on their service to contributing employers. We do not administer this plan. The Pension Plan’s benefit formula is based on credited years of service and hours worked as defined in the Pension Plan document. Our pension contributions are made in accordance with funding standards established by the Employee Retirement Income Security Act of 1974 and the Internal Revenue Code, as amended by the Pension Protection Act of 2006. The Pension Plan’s assets have been invested as determined by the Pension Plan's fiduciaries in accordance with the Pension Plan's investment policy. The Pension Plan’s asset allocation is based on the Pension Plan's investment policy and is reviewed as deemed necessary.

Stock-Based Compensation

Earnings per Share

Earnings per ShareBasic earnings per share is computed by dividing the net income (loss) by the weighted average number of common shares outstanding during the period. Diluted earnings per share is calculated based on the combined weighted average number of common shares and potentially dilutive shares. Dilutive shares include the assumed exercise of employee stock options, including market-based performance stock options based on the expected achievement of performance targets, unvested restricted stock awards, unvested restricted stock units and unvested performance stock units, including market-based performance units based on the expected achievement of performance targets. In computing diluted earnings per share, we utilize the treasury stock method.

Subsequent Events

Restricted Assets

Fair Value Measurement

Assets and Liabilities Accounted for at Fair Value on a Recurring Basis

Segment Reporting

ACCOUNTING CHANGES (Tables)

12 Months Ended

Dec. 31, 2019

Accounting Changes and Error Corrections [Abstract]

Schedule of Recent Accounting Pronouncements

Standard

Description

Effect on the Financial Statements or Other
Significant Matters

Accounting standards adopted effective January 1, 2019

ASU No. 2016-02, as amended through March 2019: Leases (Topic 842)

Standard

Description

Effect on the Financial Statements or Other
Significant Matters

Accounting standards issued pending adoption

ASU No. 2019-12: Income Taxes (Topic 740)

Reduces the complexity over accounting for income taxes by removing certain exceptions and amending guidance to improve consistent application of accounting over income taxes.

ASU No. 2017-04: Intangibles - Goodwill and Other (Topic 350)

ASU No. 2016-13: Financial Instrument Credit Losses (Topic 326)

Requires that an entity measures all of its expected credit losses for financial assets held based on historical experience, current conditions, and reasonable and supportable forecasts.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)

12 Months Ended

Dec. 31, 2019

Accounting Policies [Abstract]

Components of Property, Plant and Equipment

We provide for depreciation and amortization using the straight-line method by charges to operations in amounts that allocate the cost of the assets over their estimated useful lives as follows:


Asset Classification						Estimated Useful Life
Buildings and improvements						10-30 years
Machinery and equipment						5-10 years
Rolling stock						5-10 years
Containers						5-12 years
Furniture and Fixtures						3-8 years

A summary of property, plant and equipment is as follows:


	December 31,
	2019		2018
Land	$	28,703	$	25,490
Landfills	578,814		544,663
Landfill operating lease contracts (1)	—		121,877
Finance lease right-of-use assets (2)	24,038		—
Buildings and improvements	161,316		150,885
Machinery and equipment	168,735		153,222
Rolling stock	183,145		163,758
Containers	143,948		123,383
	1,288,699		1,283,278
Less: accumulated depreciation and amortization (1)	(844,874)		(878,701)
	$	443,825	$	404,577

REVENUE RECOGNITION (Tables)

12 Months Ended

Dec. 31, 2019

Revenue from Contract with Customer [Abstract]

Disaggregation of Revenue

A table of revenues disaggregated by service line and timing of revenue recognition by operating segment follows:

Fiscal Year Ended December 31, 2019



	Eastern		Western		Recycling		Other		Total Revenues
Collection	$	154,805	$	223,034	$	—	$	—	$	377,839
Landfill	19,362		73,657		—		—		93,019
Transfer	44,413		31,725		—		—		76,138
Customer solutions	—		—		—		79,457		79,457


Recycling	5		1,486		42,820		—		44,311


Organics	—		—		—		56,326		56,326
Transportation	—		10,811		—		1,813		12,624


Landfill gas-to-energy	890		2,686		—		—		3,576
Total revenues	$	219,475	$	343,399	$	42,820	$	137,596	$	743,290

Transferred at a point-in-time	$	159	$	921	$	19,738	$	3,468	$	24,286
Transferred over time	219,316		342,478		23,082		134,128		719,004
Total revenues	$	219,475	$	343,399	$	42,820	$	137,596	$	743,290

Fiscal Year Ended December 31, 2018



	Eastern		Western		Recycling		Other		Total Revenues
Collection	$	136,661	$	170,278	$	—	$	—	$	306,939
Landfill	28,419		66,567		—		—		94,986
Transfer	39,991		27,592		—		—		67,583
Customer solutions	—		—		—		67,464		67,464


Recycling	5		3,823		42,191		—		46,019


Organics	—		—		—		54,174		54,174
Transportation	—		14,270		—		4,096		18,366


Landfill gas-to-energy	1,397		3,732		—		—		5,129
Total Revenues	$	206,473	$	286,262	$	42,191	$	125,734	$	660,660

Transferred at a point-in-time	$	648	$	1,145	$	27,260	$	3,921	$	32,974
Transferred over time	205,825		285,117		14,931		121,813		627,686
Total revenues	$	206,473	$	286,262	$	42,191	$	125,734	$	660,660

BUSINESS COMBINATIONS (Tables)

12 Months Ended

Dec. 31, 2019

Business Combinations [Abstract]

Schedule of Purchase Price Paid for Acquisitions

The purchase price paid for these acquisitions and the allocation of the purchase price is as follows:


	Fiscal Year Ended December 31,
	2019		2018		2017
Purchase Price:
Cash used in acquisitions, net of cash acquired	$	72,118	$	86,686	$	4,823
Notes payable	2,714		—		2,400
Class A common stock issued	—		4,258		—
Other non-cash considerations	5,470		—		101
Contingent consideration and holdbacks	1,875		8,521		736
Total	82,177		99,465		8,060
Current assets	2,051		3,276		93
Non-current assets	367		—		—
Land	2,487		—		—
Buildings	5,422		7,889		—
Equipment	20,482		23,882		2,994
Other liabilities, net	(3,122)		(4,708)		(49)
Deferred tax liability	(2,385)		(937)		—
Intangible assets	31,171		29,934		2,334
Fair value of assets acquired and liabilities assumed	56,473		59,336		5,372
Excess purchase price to be allocated to goodwill	$	25,704	$	40,129	$	2,688

Schedule of Unaudited Pro forma Combined Information

The following unaudited pro forma combined information shows our operational results as though each of the acquisitions completed had occurred as of January 1, 2017.


	Fiscal Year Ended December 31,
	2019		2018		2017
Revenues	$	773,845	$	752,916	$	708,909
Operating income (loss)	$	56,997	$	49,893	$	(1,061)
Net income (loss)	$	33,893	$	12,167	$	(15,291)
Basic weighted average shares outstanding	47,226		42,688		41,846
Basic earnings (loss) per common share	$	0.72	$	0.29	$	(0.37)
Diluted weighted average shares outstanding	47,966		44,168		41,846
Diluted earnings (loss) per common share	$	0.71	$	0.28	$	(0.37)

RESTRICTED ASSETS (Tables)

12 Months Ended

Dec. 31, 2019

Receivables [Abstract]

Summary of Restricted Assets

A summary of restricted assets is as follows:


	December 31,
Non Current:	2019		2018




Restricted investment securities - landfill closure	$	1,586	$	1,248

PROPERTY, PLANT AND EQUIPMENT (Tables)

12 Months Ended

Dec. 31, 2019

Property, Plant and Equipment [Abstract]

Components of Property, Plant and Equipment

We provide for depreciation and amortization using the straight-line method by charges to operations in amounts that allocate the cost of the assets over their estimated useful lives as follows:


Asset Classification						Estimated Useful Life
Buildings and improvements						10-30 years
Machinery and equipment						5-10 years
Rolling stock						5-10 years
Containers						5-12 years
Furniture and Fixtures						3-8 years

A summary of property, plant and equipment is as follows:


	December 31,
	2019		2018
Land	$	28,703	$	25,490
Landfills	578,814		544,663
Landfill operating lease contracts (1)	—		121,877
Finance lease right-of-use assets (2)	24,038		—
Buildings and improvements	161,316		150,885
Machinery and equipment	168,735		153,222
Rolling stock	183,145		163,758
Containers	143,948		123,383
	1,288,699		1,283,278
Less: accumulated depreciation and amortization (1)	(844,874)		(878,701)
	$	443,825	$	404,577

LEASES (Tables)

12 Months Ended

Dec. 31, 2019

Leases [Abstract]

Schedule of Lease Costs and Other Lease Information

A schedule of lease costs and other lease information follows:


	Fiscal Year Ended December 31, 2019
Lease cost:
Amortization of right-of-use assets	$	2,122
Interest expense	767
Fixed lease cost - vehicles, equipment and property	9,560
Fixed lease cost - landfill operating leases	7,711
Fixed lease cost	17,271
Short-term lease cost	3,878
Variable lease cost	190
Total lease cost	$	24,228

Other information:
Cash paid for amounts included in the measurement of lease liabilities:
Financing cash flows for finance leases	$	2,601
Operating cash flows for operating leases	$	13,840
Right-of-use assets obtained in exchange for new finance lease liabilities	$	9,433
Right-of-use assets obtained in exchange for new operating lease liabilities	$	3,351

	December 31, 2019
Weighted-average remaining lease term - finance leases (years)	6.5
Weighted-average remaining lease term - operating leases (years)	12.0
Weighted-average discount rate - finance leases	5.0		%
Weighted-average discount rate - operating leases	5.1		%

Schedule of Estimated Minimum Future Finance Lease Obligations

Estimated minimum future lease obligations are as follows:


	Operating Leases		Finance Leases
Fiscal year ending December 31, 2020	$	13,210	$	4,141
Fiscal year ending December 31, 2021	11,238		3,758
Fiscal year ending December 31, 2022	8,848		3,163
Fiscal year ending December 31, 2023	6,905		2,994
Fiscal year ending December 31, 2024	6,251		2,891
Thereafter	63,717		5,332
Total lease payments	110,169		22,279
Less: interest expense	(30,104)		(3,915)
Lease liability balance	$	80,065	$	18,364

Schedule of Estimated Minimum Future Operating Lease Obligations

Estimated minimum future lease obligations are as follows:


	Operating Leases		Finance Leases
Fiscal year ending December 31, 2020	$	13,210	$	4,141
Fiscal year ending December 31, 2021	11,238		3,758
Fiscal year ending December 31, 2022	8,848		3,163
Fiscal year ending December 31, 2023	6,905		2,994
Fiscal year ending December 31, 2024	6,251		2,891
Thereafter	63,717		5,332
Total lease payments	110,169		22,279
Less: interest expense	(30,104)		(3,915)
Lease liability balance	$	80,065	$	18,364

GOODWILL AND INTANGIBLE ASSETS (Tables)

12 Months Ended

Dec. 31, 2019

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Activity and Balances Related to Goodwill by Reporting Segment

A summary of the activity and balances related to goodwill by reporting segment is as follows:


	December 31, 2018		Acquisitions		Other (1)		December 31, 2019
Eastern	$	28,154	$	2,566	$	—	$	30,720
Western	120,536		23,138		(2,619)		141,055
Recycling	12,315		—		—		12,315
Other	1,729		—		—		1,729
Total	$	162,734	$	25,704	$	(2,619)	$	185,819

(1)Relates to unregistered sale of Class A common stock that was previously held in escrow and released to us for liquidation. See Note 13, Stockholders' Equity (Deficit) for additional disclosure.


	December 31, 2017		Acquisitions		December 31, 2018
Eastern	$	19,192	$	8,962	$	28,154
Western	89,369		31,167		120,536
Recycling	12,315		—		12,315
Other	1,729		—		1,729
Total	$	122,605	$	40,129	$	162,734

Components of Intangible Assets

A summary of intangible assets is as follows:


	Covenants Not-to-Compete		Client Lists		Total
Balance, December 31, 2019
Intangible assets	$	26,162	$	71,122	$	97,284
Less accumulated amortization	(18,968)		(19,595)		(38,563)
	$	7,194	$	51,527	$	58,721


	Covenants Not-to-Compete		Client Lists		Total
Balance, December 31, 2018
Intangible assets	$	21,750	$	44,363	$	66,113
Less accumulated amortization	(17,584)		(13,762)		(31,346)
	$	4,166	$	30,601	$	34,767

Estimated Future Amortization Expense

The intangible amortization expense estimated for the five fiscal years following fiscal year 2019 and thereafter is as follows:



Estimated Future Amortization Expense as of December 31, 2019
Fiscal year ending December 31, 2020	$	8,222
Fiscal year ending December 31, 2021	$	6,826
Fiscal year ending December 31, 2022	$	6,188
Fiscal year ending December 31, 2023	$	5,993
Fiscal year ending December 31, 2024	$	6,974
Thereafter	$	24,518

FINAL CAPPING, CLOSURE AND POST-CLOSURE COSTS (Tables)

12 Months Ended

Dec. 31, 2019

Asset Retirement Obligation Disclosure [Abstract]

Changes to Accrued Capping, Closure and Post-Closure Liabilities

The changes to accrued final capping, closure and post-closure liabilities are as follows:


	Fiscal Year Ended December 31,
	2019		2018
Beginning balance	$	73,075	$	62,290
Obligations incurred	2,549		3,713
Revisions in estimates (1)	(1,538)		5,095
Accretion expense	6,227		5,556
Obligations settled (2)	(8,386)		(3,579)
Ending balance	$	71,927	$	73,075

(2)Includes amounts paid and amounts that are being processed through accounts payable as a part of our disbursement cycle.

DEBT (Tables)

12 Months Ended

Dec. 31, 2019

Debt Disclosure [Abstract]

Components of Long-Term Debt and Capital Leases

A summary of debt is as follows:


	December 31,
	2019		2018
Senior Secured Credit Facility:
Revolving Credit Facility due May 2023 ("Revolving Credit Facility"); bearing interest at LIBOR plus 1.75%	$	26,900	$	69,600
Term Loan A Facility due May 2023 (Term Loan Facility"); bearing interest at LIBOR plus 1.75%	350,000		350,000
Tax-Exempt Bonds:
New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014 ("New York Bonds 2014") due December 2044 - fixed rate interest period through 2029; bearing interest at 2.875%	25,000		25,000
New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014R-2 ("New York Bonds 2014R-2") due December 2044 - fixed rate interest period through 2026; bearing interest at 3.125%	15,000		15,000
Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2005R-3 ("FAME Bonds 2005R-3") due January 2025 - fixed rate interest period through 2025; bearing interest at 5.25%	25,000		25,000
Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2015R-1 ("FAME Bonds 2015R-1") due August 2035 - fixed rate interest period through 2025; bearing interest at 5.125%	15,000		15,000
Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2015R-2 ("FAME Bonds 2015R-2") due August 2035 - fixed rate interest period through 2025; bearing interest at 4.375%	15,000		15,000
Vermont Economic Development Authority Solid Waste Disposal Long-Term Revenue Bonds Series 2013 ("Vermont Bonds") due April 2036 - fixed rate interest period through 2028; bearing interest at 4.625%	16,000		16,000
Business Finance Authority of the State of New Hampshire Solid Waste Disposal Revenue Bonds Series 2013 ("New Hampshire Bonds") due April 2029 - fixed rate interest period through 2029; bearing interest at 2.95%	11,000		11,000
Other:
Finance leases maturing through December 2107; bearing interest at a weighted average of 5.0%	18,364		11,248
Notes payable maturing through June 2027; bearing interest at a weighted average of 3.5%	5,464		2,401
Principal amount of debt	522,728		555,249
Less—unamortized discount and debt issuance costs (1)	9,406		10,950
Debt less unamortized discount and debt issuance costs	513,322		544,299
Less—current maturities of debt	4,301		2,298
	$	509,021	$	542,001

(1)A summary of unamortized discount and debt issuance costs by debt instrument follows:


	December 31,
	2019		2018
Revolving Credit Facility and Term Loan Facility (collectively, the "Credit Facility")	$	5,478	$	7,118
New York Bonds 2014	1,057		847
New York Bonds 2014R-2	390		450
FAME Bonds 2005R-3	432		517
FAME Bonds 2015R-1	552		622
FAME Bonds 2015R-2	417		493
Vermont Bonds	541		595
New Hampshire Bonds	539		308
	$	9,406	$	10,950

Components of Interest Expense

The components of interest expense are as follows:


	Fiscal Year Ended December 31,
	2019		2018		2017
Interest expense on long-term debt and finance leases	$	22,553	$	23,431	$	22,060
Amortization of debt issuance costs and discount on long-term debt	2,293		2,449		2,692
Letter of credit fees	519		554		703
Less: capitalized interest	(263)		(140)		(295)
Total interest expense	$	25,102	$	26,294	$	25,160

Schedule of Cash Flow Hedges Related to Derivative Instruments

A summary of the effect of cash flow hedges related to derivative instruments on the consolidated balance sheet follows:


		Fair Value
	Balance Sheet Location	December 31, 2019		December 31, 2018
Interest rate swaps	Other current assets	$	—	$	338
Interest rate swaps	Other non-current assets	—		482
Total		$	—	$	820

Interest rate swaps	Other accrued liabilities	$	1,824	$	387
Interest rate swaps	Other long-term liabilities	3,603		1,555
Total		$	5,427	$	1,942

Interest rate swaps	Accumulated other comprehensive loss, net	$	(5,929)	$	(1,196)
Interest rate swaps - tax provision	Accumulated other comprehensive loss, net	(112)		(112)
		$	(6,041)	$	(1,308)

Schedule of Gain (Loss) On Cash Flow Hedges

A summary of the amount of gain or (loss) on cash flow hedging relationships related to interest rate swaps reclassified from accumulated other comprehensive loss, net into earnings follows:


	Fiscal Year Ended December 31,
	2019		2018		2017
Statement of Operations Location	(Expense) Income
Interest expense	$	(553)	$	(363)	$	(421)

Schedule of Future Maturities of Debt

Aggregate principal maturities of debt are as follows:



Estimated Future Payments as of December 31, 2019
Fiscal year ending December 31, 2020	$	4,300
Fiscal year ending December 31, 2021	3,593
Fiscal year ending December 31, 2022	5,358
Fiscal year ending December 31, 2023	379,945
Fiscal year ending December 31, 2024	2,893
Thereafter	126,639
	$	522,728

COMMITMENTS AND CONTINGENCIES (Tables)

12 Months Ended

Dec. 31, 2019

Site Contingency [Line Items]

Schedule of Total Expected Environmental Remediation Payments for Succeeding Year

The total expected environmental remediation payments, in today’s dollars, for each of the five succeeding fiscal years and the aggregate amount thereafter are as follows:


Estimated Future Environmental Remediation Payments as of December 31, 2019
Fiscal year ending December 31, 2020	$	446
Fiscal year ending December 31, 2021	382
Fiscal year ending December 31, 2022	392
Fiscal year ending December 31, 2023	367
Fiscal year ending December 31, 2024	386
Thereafter	4,630
Total	$	6,603

Reconciliation of Expected Aggregate Non-inflated, Undiscounted Environmental Remediation Liability to Amount Recognized in Statement of Financial Position

A reconciliation of the expected aggregate non-inflated, undiscounted environmental remediation liability to the amount recognized in the statement of financial position is as follows:



Undiscounted liability	$	6,603
Less discount, net	(856)
Liability balance - December 31, 2019	$	5,747

Southbridge Landfill

Site Contingency [Line Items]

Schedule of Environmental Remedial Liability

A summary of the changes to the environmental remediation liability associated with the Southbridge Landfill follows:



	Fiscal Year Ended December 31,
	2019		2018
Beginning balance	$	5,173	$	5,936
Accretion expense	124		—
Obligations incurred	—		152

Obligations settled (1)	(701)		(915)
Ending balance	$	4,596	$	5,173

(1)Includes amounts that are being processed through accounts payable as a part of our disbursements cycle.

Potsdam Environmental Remediation Liability

Site Contingency [Line Items]

Schedule of Environmental Remedial Liability

A summary of the changes to the environmental remediation liability associated with the Potsdam site follows:


	Fiscal Year Ended December 31,
	2019		2018
Beginning balance	$	5,614	$	5,758

Obligations settled (1)	(4,463)		(171)
Obligations incurred	—		27

Ending balance	$	1,151	$	5,614

(1)Includes amounts that are being processed through accounts payable as a part of our disbursements cycle.

STOCKHOLDERS' EQUITY (Tables)

12 Months Ended

Dec. 31, 2019

Equity [Abstract]

Summary of Stock Option Activity

A summary of stock option activity is as follows:


	Stock Options	Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (years)	Aggregate Intrinsic Value
Outstanding, December 31, 2018	669	$	6.37
Granted	—	$	—
Exercised	(571)	$	5.88
Forfeited or expired	—	$	—

Outstanding, December 31, 2019	98	$	9.20	5.8	$	3,614
Exercisable, December 31, 2019	98	$	9.20	5.8	$	3,614

Summary of Restricted Stock, Restricted Stock Unit and Performance Stock Unit Activity

A summary of restricted stock, restricted stock unit and performance stock unit activity is as follows:


	Restricted Stock, Restricted Stock Units, and Performance Stock Units (1)	Weighted Average Grant Price		Weighted Average Remaining Contractual Term (years)	Aggregate Intrinsic Value
Outstanding, December 31, 2018	686	$	15.56
Granted	166	$	37.24
Class A common stock vested	(449)	$	12.38
Forfeited or canceled	(10)	$	23.41
Outstanding, December 31, 2019	393	$	28.23	1.3	$	6,992
Unvested, December 31, 2019	579	$	29.69	1.4	$	9,458

Accumulated Other Comprehensive Income (Loss)

The changes in the balances of each component of accumulated other comprehensive income (loss) are as follows:


	Marketable Securities		Interest Rate Swaps		Total
Balance as of December 31, 2016	$	(68)	$	—	$	(68)

Other comprehensive income (loss) before reclassifications	59		(143)		(84)
Amounts reclassified from accumulated other comprehensive income (loss)	—		421		421
Income tax expense related to items in other comprehensive income (loss)	27		(112)		(85)
Other comprehensive income, net	86		166		252
Balance as of December 31, 2017	18		166		184
Cumulative effect of new accounting principle	(18)		—		(18)
Other comprehensive loss before reclassifications	—		(1,837)		(1,837)
Amounts reclassified from accumulated other comprehensive loss	—		363		363

Other comprehensive loss	—		(1,474)		(1,474)
Balance as of December 31, 2018	—		(1,308)		(1,308)

Other comprehensive loss before reclassifications	—		(5,286)		(5,286)
Amounts reclassified from accumulated other comprehensive loss	—		553		553

Other comprehensive loss	—		(4,733)		(4,733)
Balance as of December 31, 2019	$	—	$	(6,041)	$	(6,041)

Reclassification Out of Accumulated Other Comprehensive Income (Loss)

A summary of reclassifications out of accumulated other comprehensive income (loss) for fiscal years 2019, 2018 and 2017 is as follows:


	Fiscal Year Ended December 31,
	2019		2018		2017
Details About Accumulated Other Comprehensive Income (Loss) Components	Amounts Reclassified Out of Accumulated Other Comprehensive Income (Loss)							Affected Line Item in the Consolidated Statements of Operations
Interest rate swaps	$	553	$	363	$	421	Interest expense
	553		363		421		Income (loss) before income taxes
	—		—		—		Benefit for income taxes
	$	553	$	363	$	421	Net income (loss)

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)

12 Months Ended

Dec. 31, 2019

Fair Value Disclosures [Abstract]

Assets and Liabilities Measured at Fair Value on Recurring Basis

Summaries of our financial assets and liabilities that are measured at fair value on a recurring basis are as follows:


	Fair Value Measurement at December 31, 2019 Using:
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:



Restricted investment securities - landfill closure	$	1,586	$	—	$	—
Liabilities:
Interest rate swaps	$	—	$	5,427	$	—


	Fair Value Measurement at December 31, 2018 Using:
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:

Restricted investment securities - landfill closure	$	1,248	$	—	$	—
Interest rate swaps	—		820		—
	$	1,248	$	820	$	—
Liabilities:
Interest rate swaps	$	—	$	1,942	$	—

EMPLOYEE BENEFIT PLANS EMPLOYEE BENEFIT PLANS (Tables)

12 Months Ended

Dec. 31, 2019

Retirement Benefits [Abstract]

Schedule of Multiemployer Defined Benefit Pension Plans

The following table outlines the status of the Pension Plan:


Pension Fund	EIN/Pension Plan Number	Pension Protection Act Zone Status			Funding Improvement or Rehabilitation Plan Status		Contributions to Plan								Expiration Date of CBA
													Fiscal Year Ended December 31,
			2019	2018					2019			2018		2017
New England Teamsters and Trucking Industry Pension Fund	04-6372430	Critical and declining	Critical and declining	Implemented	$	409	$	726		$	627		June 30, 2020

INCOME TAXES (Tables)

12 Months Ended

Dec. 31, 2019

Income Tax Disclosure [Abstract]

Schedule of Benefit for Income Taxes

A summary of the benefit for income taxes is as follows:


	Fiscal Year Ended December 31,
	2019		2018		2017
Federal
Current	$	(951)	$	(1,902)	$	—

Deferred	(699)		1,255		(15,614)
	(1,650)		(647)		(15,614)
State
Current	321		2,575		301
Current benefit of loss carryforwards	—		(2,307)		(28)
Deferred	(545)		(5)		88
	(224)		263		361
Benefit for income taxes	$	(1,874)	$	(384)	$	(15,253)

Schedule of Difference in Benefit for Income Taxes

The differences in the benefit for income taxes and the amounts determined by applying the Federal statutory rate to income before provision for income taxes are as follows:


	Fiscal Year Ended December 31,
	2019			2018			2017
Federal statutory rate	21		%	21		%	35		%
Tax at statutory rate	$	6,254		$	1,268		$	(12,968)
State income taxes, net of federal benefit	(161)			(89)			(1,959)
Decrease in net federal deferred tax assets before valuation allowance change due to federal rate change	—			—			33,700
Decrease in valuation allowance by 80% of indefinite lived deferred liabilities due to US tax reform	—			—			(12,758)
Other changes in valuation allowance, including the federal rate change in fiscal year 2017	(978)			(1,613)			(18,848)
Deductible stock awards	(7,235)			(2,048)			(1,825)
Non-deductible expenses	638			633			542
Non-deductible officer compensation	314			2,214			—

Tax credits	(82)			(686)			(1,000)



Other, net	(624)			(63)			(137)
Benefit for income taxes	$	(1,874)		$	(384)		$	(15,253)

Schedule of Deferred Tax Assets and Liabilities


	December 31,
	2019		2018
Deferred tax assets:
Net operating loss carryforwards	$	45,900	$	31,241
Accrued expenses and reserves	36,342		34,647
General business tax credit carryforwards	6,273		6,192
Book over tax depreciation of property and equipment	2,882		19,048
Unrealized loss on hedges and swaps	1,768		—
Stock awards	1,746		2,310
Alternative minimum tax credit carryforwards	951		1,902

Other	2,576		3,023
Total deferred tax assets	98,438		98,363
Less: valuation allowance	(69,402)		(69,189)
Total deferred tax assets after valuation allowance	29,036		29,174
Deferred tax liabilities:
Amortization of intangibles	(22,910)		(22,026)
Other	(192)		(73)
Total deferred tax liabilities	(23,102)		(22,099)
Net deferred tax asset	$	5,934	$	7,075

Schedule of Reconciliation of Gross Unrecognized Tax Benefits

A reconciliation of the beginning and ending amount of gross unrecognized tax benefits is as follows:


	Fiscal Year Ended December 31,
	2019		2018
Unrecognized tax benefits at beginning of period	$	2	$	1,941


Reductions resulting from lapse of statute of limitations	(1)		(1,939)


Unrecognized tax benefits at end of period	$	1	$	2

OTHER ITEMS AND CHARGES (Tables)

12 Months Ended

Dec. 31, 2019

Unusual or Infrequent Items, or Both [Abstract]

Charges Associated with Closure of Southbridge Landfill

Accordingly, in fiscal years 2019, 2018 and 2017, we recorded charges associated with the closure of our Southbridge Landfill as follows:


	Fiscal Year Ended December 31,
	2019		2018		2017
Asset impairment charge (1)	$	—	$	—	$	47,999
Project development charge (2)	—		—		9,149
Environmental remediation charge (3)	—		—		6,379
Contract settlement charge (4)	—		8,724		—
Landfill closure project charge (5)	—		6,012		—
Charlton settlement charge (6)	—		1,216		—
Legal and transaction costs (7)	2,709		2,102		1,656
Recovery on insurance settlement (8)	—		(10,000)		—
Southbridge Landfill closure charge, net	$	2,709	$	8,054	$	65,183

(2)We wrote-off deferred costs associated with Southbridge Landfill permitting activities no longer deemed viable.

(3)We recorded an environmental remediation charge associated with the installation of a municipal waterline.

(5)We recorded a landfill closure project charge associated with increased costs under the revised closure plan at our Southbridge Landfill.

(6)We established a reserve associated with settlement of the Town of Charlton's claim against us.

(7)We incurred legal costs as well as other costs associated with various matters as part of the Southbridge Landfill closure.

(8)We recorded a recovery on an environmental insurance settlement associated with the Southbridge Landfill closure.

EARNINGS PER SHARE (Tables)

12 Months Ended

Dec. 31, 2019

Earnings Per Share [Abstract]

Schedule of Numerator and Denominator Used in Computation of Earnings per Share

A summary of the numerator and denominators used in the computation of earnings per share is as follows:


	Fiscal Year Ended December 31,
	2019		2018		2017
Numerator:
Net income (loss)	$	31,653	$	6,420	$	(21,799)
Denominator:
Class A common stock	46,803		41,944		41,298
Class B common stock	988		988		988
Shares to be issued - acquisition	36		103		—
Unvested restricted stock	—		(9)		(38)
Effect of weighted average shares outstanding	(601)		(338)		(402)
Basic weighted average common shares outstanding	47,226		42,688		41,846
Impact of potentially dilutive securities:
Dilutive effect of stock options and stock awards	740		1,480		—
Diluted weighted average common shares outstanding	47,966		44,168		41,846
Antidilutive potentially issuable shares	2		2		2,219

SEGMENT REPORTING (Tables)

12 Months Ended

Dec. 31, 2019

Segment Reporting [Abstract]

Summary of Financial Information by Reportable Segment

Fiscal Year Ended December 31, 2019


Segment	Outside revenues		Inter-company revenue		Depreciation and amortization		Operating income (loss)		Interest expense, net		Capital expenditures		Goodwill		Total assets
Eastern	$	219,475	$	54,738	$	24,322	$	9,503	$	218	$	24,499	$	30,720	$	207,060
Western	343,399		97,339		47,666		41,883		63		63,540		141,054		598,910
Recycling	42,820		9,400		4,009		(814)		160		9,719		12,316		56,688
Other	137,596		2,443		3,793		2,503		24,294		5,407		1,729		69,524
Eliminations	—		(163,920)		—		—		—		—		—		—
Total	$	743,290	$	—	$	79,790	$	53,075	$	24,735	$	103,165	$	185,819	$	932,182

Fiscal Year Ended December 31, 2018


Segment	Outside revenues		Inter-company revenue		Depreciation and amortization		Operating income (loss)		Interest expense, net		Capital expenditures		Goodwill		Total assets
Eastern	$	206,473	$	52,866	$	26,538	$	4,684	$	12	$	23,393	$	28,154	$	184,679
Western	286,262		81,515		35,843		41,529		(148)		41,850		120,536		428,934
Recycling	42,191		6,426		4,345		(7,805)		140		4,476		12,315		48,629
Other	125,734		1,982		3,782		1,325		26,017		3,513		1,729		70,168
Eliminations	—		(142,789)		—		—		—		—		—		—
Total	$	660,660	$	—	$	70,508	$	39,733	$	26,021	$	73,232	$	162,734	$	732,410

Fiscal Year Ended December 31, 2017


Segment	Outside revenues		Inter-company revenue		Depreciation and amortization		Operating income (loss)		Interest expense, net		Capital expenditures		Goodwill		Total assets
Eastern	$	181,170	$	50,335	$	23,815	$	(51,867)	$	3	$	17,153	$	19,192	$	157,248
Western	250,771		71,510		30,766		35,035		(220)		42,082		89,369		344,324
Recycling	62,307		246		4,125		2,805		143		2,006		12,315		48,612
Other	105,061		1,881		3,396		1,444		24,961		3,621		1,729		64,765
Eliminations	—		(123,972)		—		—		—		—		—		—
Total	$	599,309	$	—	$	62,102	$	(12,583)	$	24,887	$	64,862	$	122,605	$	614,949

Summary of Revenue Attributable to Services Provided by Company

Amount of our total revenue attributable to services provided are as follows:


	Fiscal Year Ended December 31,
	2019						2018						2017
Collection	$	372,041	50.1	%	$	303,418	45.9	%	$	263,688	44.0	%
Disposal	181,895		24.5	%	181,110		27.4	%	160,073		26.7	%
Power generation	3,576		0.5	%	5,129		0.8	%	5,375		0.9	%
Processing	7,175		0.9	%	7,174		1.1	%	7,994		1.3	%
Solid waste operations	564,687		76.0	%	496,831		75.2	%	437,130		72.9	%
Organics	56,326		7.5	%	54,174		8.2	%	39,815		6.6	%
Customer solutions	79,457		10.7	%	67,464		10.2	%	60,057		10.1	%
Recycling	42,820		5.8	%	42,191		6.4	%	62,307		10.4	%
Total revenues	$	743,290	100.0	%	$	660,660	100.0	%	$	599,309	100.0	%

QUARTERLY FINANCIAL INFORMATION (UNAUDITED) (Tables)

12 Months Ended

Dec. 31, 2019

Quarterly Financial Information Disclosure [Abstract]

Summary of Quarterly Financial Information

The following is a summary of certain items in the consolidated statements of operations by quarter:


Fiscal Year 2019	First Quarter		Second Quarter		Third Quarter		Fourth Quarter
Revenues	$	163,664	$	187,459	$	198,547	$	193,619
Operating income	$	4,442	$	15,544	$	18,485	$	14,604
Net (loss) income	$	(1,714)	$	11,915	$	12,386	$	9,066

Earnings per common share:
Basic weighted average common shares outstanding	45,913		47,464		47,690		47,811
Basic earnings per share	$	(0.04)	$	0.25	$	0.26	$	0.19
Diluted weighted average common shares outstanding	42,913		48,221		48,361		48,583
Diluted earnings per share	$	(0.04)	$	0.25	$	0.26	$	0.19


Fiscal Year 2018	First Quarter		Second Quarter		Third Quarter		Fourth Quarter
Revenues	$	147,455	$	165,649	$	172,832	$	174,724
Operating income (loss)	$	838	$	15,149	$	28,884	$	(5,138)
Net (loss) income	$	(3,910)	$	1,704	$	22,302	$	(13,676)

Earnings per common share:
Basic weighted average common shares outstanding	42,370		42,661		42,779		42,936
Basic earnings per share	$	(0.09)	$	0.04	$	0.52	$	(0.32)
Diluted weighted average common shares outstanding	42,370		43,916		44,175		42,936
Diluted earnings per share	$	(0.09)	$	0.04	$	0.50	$	(0.32)

BASIS OF PRESENTATION (Detail)	12 Months Ended
BASIS OF PRESENTATION (Detail)	Dec. 31, 2019 Segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Operating segments	2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Estimated Useful Lives of Assets (Detail)	12 Months Ended
	Dec. 31, 2019
Minimum \| Buildings and improvements
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful life	10 years
Minimum \| Machinery and equipment
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful life	5 years
Minimum \| Rolling stock
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful life	5 years
Minimum \| Containers
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful life	5 years
Minimum \| Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful life	3 years
Maximum \| Buildings and improvements
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful life	30 years
Maximum \| Machinery and equipment
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful life	10 years
Maximum \| Rolling stock
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful life	10 years
Maximum \| Containers
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful life	12 years
Maximum \| Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful life	8 years

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Landfill and Lease Accounting (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) Agreement	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Property, Plant and Equipment [Line Items]
Capitalized interest	$ 263	$ 140	$ 295
Closure and post-closure costs incurrence period	30 years
Estimate of inflation rate	1.60%
Accretion expense	$ 6,227	5,556
Number of operation and management agreements entered into \| Agreement	3
Closure And Post Closure Costs
Property, Plant and Equipment [Line Items]
Accretion expense	$ 6,227	5,556	$ 4,401
Surety bond	220,633	201,177
Letters of credit	$ 0	$ 0
Discount rate \| Minimum
Property, Plant and Equipment [Line Items]
Asset retirement obligation measurement input	8.70%
Discount rate \| Maximum
Property, Plant and Equipment [Line Items]
Asset retirement obligation measurement input	10.00%

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Goodwill and Intangible Assets (Detail)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Intangible assets, useful life (no more than)	10 years

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Investments in Unconsolidated Entities (Detail) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Investments under equity method of accounting	$ 0	$ 0
Cost method investments	$ 11,264,000	$ 11,264,000

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Self-Insurance Liabilities and Related Costs (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Capital Leased Assets [Line Items]
Maximum exposure automobile plan per individual event	$ 1,250,000
Self insurance reserves	16,853,000	$ 15,040,000
Automobile Plan
Capital Leased Assets [Line Items]
Maximum exposure automobile plan per individual event	$ 1,200,000

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES -Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Rebates	$ (193,619)	$ (198,547)	$ (187,459)	$ (163,664)	$ (174,724)	$ (172,832)	$ (165,649)	$ (147,455)	$ (743,290)	$ (660,660)	$ (599,309)
Gross receivables from contracts	80,191				73,500				80,191	73,500
Contract liabilities	$ 2,299				$ 3,074				2,299	3,074
Difference between revenue guidance in effect before and after topic 606 \| Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Rebates									$ 4,428	$ 6,279

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Asset Impairments (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Goodwill impairment incurred	$ 0	$ 0	$ 0
Impairment of investments	0	1,069,000	$ 0
Cost method investments	$ 11,264,000	11,264,000
Recycle Rewards Inc
Segment Reporting Information [Line Items]
Impairment of investments		$ 1,069,000
Outstanding common stock percentage	6.80%
Eastern
Segment Reporting Information [Line Items]
Percentage of fair value in excess of carrying amount	34.40%
Western
Segment Reporting Information [Line Items]
Percentage of fair value in excess of carrying amount	34.40%
Recycling
Segment Reporting Information [Line Items]
Percentage of fair value in excess of carrying amount	34.40%
Customer Solutions
Segment Reporting Information [Line Items]
Percentage of fair value in excess of carrying amount	34.40%

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Defined Benefit Pension Plan (Details)	12 Months Ended
	Dec. 31, 2019 plan
Multiemployer Pension Plans \| New England Teamsters and Trucking Industry Pension Fund
Multiemployer Plans [Line Items]
Number of plans	1

BUSINESS COMBINATIONS - Narrative (Detail)	12 Months Ended
BUSINESS COMBINATIONS - Narrative (Detail)	Dec. 31, 2019 vote transfer_station	Dec. 31, 2018 vote transfer_station	Dec. 31, 2017 transfer_station
Business Acquisition [Line Items]
Number of businesses acquired	9	9	4
Intangible assets, useful life	10 years
Minimum
Business Acquisition [Line Items]
Intangible assets, useful life	5 years
Maximum
Business Acquisition [Line Items]
Intangible assets, useful life	10 years
Eastern \| Solid Waste Collection Business
Business Acquisition [Line Items]
Number of businesses acquired	3		1
Eastern \| Collection Business
Business Acquisition [Line Items]
Number of businesses acquired		2
Western \| Solid Waste Collection Business
Business Acquisition [Line Items]
Number of businesses acquired	4	6	3
Western \| Transfer Business
Business Acquisition [Line Items]
Number of businesses acquired		1

BUSINESS COMBINATIONS - Schedule of Purchase Price Paid for Acquisitions (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Purchase Price:
Cash used in acquisitions, net of cash acquired	$ 75,379	$ 88,918	$ 5,056
Excess purchase price to be allocated to goodwill	185,819	162,734	122,605
Transfer Stations Acquisition
Purchase Price:
Cash used in acquisitions, net of cash acquired	72,118	86,686	4,823
Notes payable	2,714	0	2,400
Class A common stock issued	0	4,258	0
Other non-cash considerations	5,470	0	101
Contingent consideration and holdbacks	1,875	8,521	736
Total	82,177	99,465	8,060
Current assets	2,051	3,276	93
Non-current assets	367	0	0
Land	2,487	0	0
Buildings	5,422	7,889	0
Equipment	20,482	23,882	2,994
Other liabilities, net	(3,122)	(4,708)	(49)
Deferred tax liability	(2,385)	(937)	0
Intangible assets	31,171	29,934	2,334
Fair value of assets acquired and liabilities assumed	56,473	59,336	5,372
Excess purchase price to be allocated to goodwill	$ 25,704	$ 40,129	$ 2,688

BUSINESS COMBINATIONS - Schedule of Unaudited Pro forma Combined Information (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Combinations [Abstract]
Revenues									$ 773,845	$ 752,916	$ 708,909
Operating income (loss)									56,997	49,893	(1,061)
Net income (loss)									$ 33,893	$ 12,167	$ (15,291)
Basic weighted average shares outstanding	47,811	47,690	47,464	45,913	42,936	42,779	42,661	42,370	47,226	42,688	41,846
Basic earnings (loss) per common share (in dollars per share)									$ 0.72	$ 0.29	$ (0.37)
Diluted weighted average shares outstanding	48,583	48,361	48,221	42,913	42,936	44,175	43,916	42,370	47,966	44,168	41,846
Diluted earnings (loss) per common share (in dollars per share)									$ 0.71	$ 0.28	$ (0.37)

RESTRICTED ASSETS (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Receivables [Abstract]
Restricted investment securities - landfill closure	$ 1,586	$ 1,248

PROPERTY, PLANT AND EQUIPMENT - Components of Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		$ 1,283,278
Finance lease right-of-use assets	$ 24,038
Property, plant and equipment and finance lease right-of-use asset, gross	1,288,699
Less: accumulated depreciation and amortization	(844,874)
Less: accumulated depreciation and amortization		(878,701)
Property, plant and equipment and finance lease right-of-use asset, net	443,825
Property, plant and equipment, net		404,577
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	28,703	25,490
Landfills
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	578,814	544,663
Landfill operating lease contracts
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	0	121,877
Buildings and improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	161,316	150,885
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	168,735	153,222
Rolling stock
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	183,145	163,758
Containers
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 143,948	$ 123,383

PROPERTY, PLANT AND EQUIPMENT - Narrative (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 45,060	$ 35,351	$ 32,131
Depletion expense on operating lease contracts		9,724	9,646
Landfills
Property, Plant and Equipment [Line Items]
Amortization expense	$ 27,512	$ 31,841	$ 27,910

LEASES - Schedule of Lease Costs and Other Lease Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)
Lease cost:
Amortization of right-of-use assets	$ 2,122
Interest expense	767
Fixed lease cost	17,271
Short-term lease cost	3,878
Variable lease cost	190
Total lease cost	24,228
Cash paid for amounts included in the measurement of lease liabilities:
Financing cash flows for finance leases	2,601
Operating cash flows for operating leases	13,840
Right-of-use assets obtained in exchange for new finance lease liabilities	9,433
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 3,351
Weighted-average remaining lease term - finance leases (years)	6 years 6 months
Weighted-average remaining lease term - operating leases (years)	12 years
Weighted-average discount rate - finance leases	5.00%
Weighted-average discount rate - operating leases	5.10%
Machinery and equipment
Lease cost:
Fixed lease cost	$ 9,560
Landfills
Lease cost:
Fixed lease cost	$ 7,711

LEASES - Schedule of Estimated Minimum Future Lease Obligations (Details) $ in Thousands	Dec. 31, 2019 USD ($)
Operating Leases
Fiscal year ending December 31, 2020	$ 13,210
Fiscal year ending December 31, 2021	11,238
Fiscal year ending December 31, 2022	8,848
Fiscal year ending December 31, 2023	6,905
Fiscal year ending December 31, 2024	6,251
Thereafter	63,717
Total lease payments	110,169
Less: interest expense	(30,104)
Lease liability balance	80,065
Finance Leases
Fiscal year ending December 31, 2020	4,141
Fiscal year ending December 31, 2021	3,758
Fiscal year ending December 31, 2022	3,163
Fiscal year ending December 31, 2023	2,994
Fiscal year ending December 31, 2024	2,891
Thereafter	5,332
Total lease payments	22,279
Less: interest expense	(3,915)
Lease liability balance	$ 18,364

GOODWILL AND INTANGIBLE ASSETS - Schedule of Activity and Balances Related to Goodwill by Reporting Segment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 162,734	$ 122,605
Acquisitions	25,704	40,129
Other	(2,619)
Goodwill, ending balance	185,819	162,734
Eastern
Goodwill [Roll Forward]
Goodwill, beginning balance	28,154	19,192
Acquisitions	2,566	8,962
Other	0
Goodwill, ending balance	30,720	28,154
Western
Goodwill [Roll Forward]
Goodwill, beginning balance	120,536	89,369
Acquisitions	23,138	31,167
Other	(2,619)
Goodwill, ending balance	141,055	120,536
Recycling
Goodwill [Roll Forward]
Goodwill, beginning balance	12,315	12,315
Acquisitions	0	0
Other	0
Goodwill, ending balance	12,315	12,315
Other
Goodwill [Roll Forward]
Goodwill, beginning balance	1,729	1,729
Acquisitions	0	0
Other	0
Goodwill, ending balance	$ 1,729	$ 1,729

GOODWILL AND INTANGIBLE ASSETS - Components of Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Intangible assets	$ 97,284	$ 66,113
Less accumulated amortization	(38,563)	(31,346)
Intangible assets, net	58,721	34,767
Intangible amortization expenses	7,218	3,316	$ 2,061
Covenants Not-to-Compete
Finite-Lived Intangible Assets [Line Items]
Intangible assets	26,162	21,750
Less accumulated amortization	(18,968)	(17,584)
Intangible assets, net	7,194	4,166
Client Lists
Finite-Lived Intangible Assets [Line Items]
Intangible assets	71,122	44,363
Less accumulated amortization	(19,595)	(13,762)
Intangible assets, net	$ 51,527	$ 30,601

GOODWILL AND INTANGIBLE ASSETS - Estimated Future Amortization Expense (Detail) $ in Thousands	Dec. 31, 2019 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Fiscal year ending December 31, 2020	$ 8,222
Fiscal year ending December 31, 2021	6,826
Fiscal year ending December 31, 2022	6,188
Fiscal year ending December 31, 2023	5,993
Fiscal year ending December 31, 2024	6,974
Thereafter	$ 24,518

FINAL CAPPING, CLOSURE AND POST-CLOSURE COSTS (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	$ 73,075	$ 62,290
Obligations incurred	2,549	3,713
Revisions in estimates	(1,538)	5,095
Accretion expense	6,227	5,556
Obligations settled	(8,386)	(3,579)
Ending balance	$ 71,927	$ 73,075

DEBT - Components of Long-Term Debt and Capital Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Finance leases maturing through December 2107; bearing interest at a weighted average of 5.2%	$ 18,364
Principal amount of debt	522,728	$ 555,249
Less—unamortized discount and debt issuance costs	9,406	10,950
Debt less unamortized discount and debt issuance costs	513,322	544,299
Less—current maturities of debt	4,301	2,298
Debt, less current portion	$ 509,021	542,001
Weighted-average discount rate - finance leases	5.00%
Revolving Credit Facility due May 2023 ("Revolving Credit Facility"); bearing interest at LIBOR plus 1.75%
Debt Instrument [Line Items]
Principle amount of debt	$ 26,900
Principal amount of debt		69,600
New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014 ("New York Bonds 2014") due December 2044 - fixed rate interest period through 2029; bearing interest at 2.875%
Debt Instrument [Line Items]
Principle amount of debt	25,000
Principal amount of debt		25,000
Less—unamortized discount and debt issuance costs	$ 1,057	847
Stated interest rate	2.875%
New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014R-2 ("New York Bonds 2014R-2") due December 2044 - fixed rate interest period through 2026; bearing interest at 3.125%
Debt Instrument [Line Items]
Principle amount of debt	$ 15,000
Principal amount of debt		15,000
Less—unamortized discount and debt issuance costs	$ 390	450
Stated interest rate	3.125%
Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2005R-3 ("FAME Bonds 2005R-3") due January 2025 - fixed rate interest period through 2025; bearing interest at 5.25%
Debt Instrument [Line Items]
Principle amount of debt	$ 25,000
Principal amount of debt		25,000
Less—unamortized discount and debt issuance costs	$ 432	517
Stated interest rate	5.25%
Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2015R-1 ("FAME Bonds 2015R-1") due August 2035 - fixed rate interest period through 2025; bearing interest at 5.125%
Debt Instrument [Line Items]
Principle amount of debt	$ 15,000
Principal amount of debt		15,000
Less—unamortized discount and debt issuance costs	$ 552	622
Stated interest rate	5.125%
Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2015R-2 ("FAME Bonds 2015R-2") due August 2035 - fixed rate interest period through 2025; bearing interest at 4.375%
Debt Instrument [Line Items]
Principle amount of debt	$ 15,000
Principal amount of debt		15,000
Less—unamortized discount and debt issuance costs	$ 417	493
Stated interest rate	4.375%
Vermont Economic Development Authority Solid Waste Disposal Long-Term Revenue Bonds Series 2013 ("Vermont Bonds") due April 2036 - fixed rate interest period through 2028; bearing interest at 4.625%
Debt Instrument [Line Items]
Principle amount of debt	$ 16,000
Principal amount of debt		16,000
Less—unamortized discount and debt issuance costs	$ 541	595
Stated interest rate	4.625%
Business Finance Authority of the State of New Hampshire Solid Waste Disposal Revenue Bonds Series 2013 ("New Hampshire Bonds") due April 2029 - fixed rate interest period through 2029; bearing interest at 2.95%
Debt Instrument [Line Items]
Principle amount of debt	$ 11,000
Principal amount of debt		11,000
Less—unamortized discount and debt issuance costs	$ 539	308
Stated interest rate	2.95%
Finance leases maturing through December 2107; bearing interest at a weighted average of 5.0%
Debt Instrument [Line Items]
Principal amount of debt		11,248
Notes payable maturing through June 2027; bearing interest at a weighted average of 3.5%
Debt Instrument [Line Items]
Principle amount of debt	$ 5,464
Principal amount of debt		2,401
Weighted average interest rate	3.50%
Credit Facility
Debt Instrument [Line Items]
Less—unamortized discount and debt issuance costs	$ 5,478	7,118
Term Loan A Facility due May 2023 (Term Loan Facility"); bearing interest at LIBOR plus 1.75% \| Secured Debt
Debt Instrument [Line Items]
Principle amount of debt	$ 350,000
Principal amount of debt		$ 350,000
LIBOR \| Revolving Credit Facility due May 2023 ("Revolving Credit Facility"); bearing interest at LIBOR plus 1.75%
Debt Instrument [Line Items]
Basis spread on variable rate	1.75%
LIBOR \| Term Loan A Facility due May 2023 (Term Loan Facility"); bearing interest at LIBOR plus 1.75% \| Secured Debt
Debt Instrument [Line Items]
Basis spread on variable rate	1.75%

DEBT - Credit Facility (Details)	12 Months Ended
DEBT - Credit Facility (Details)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Secured Debt \| Term Loan Facility \| Line of Credit
Line of Credit Facility [Line Items]
Aggregate principal amount issued		$ 350,000,000
Secured Debt \| Term Loan B Facility
Line of Credit Facility [Line Items]
Aggregate principal amount issued		350,000,000
Facility term	5 years
Net leverage ratio	2.25
Secured Debt \| Term Loan B Facility \| LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.25%
Secured Debt \| Term Loan B Facility \| LIBOR \| Maximum
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.75%
Revolving Credit Facility
Line of Credit Facility [Line Items]
Additional revolver capacity	$ 125,000,000
Revolving Credit Facility \| Revolving Credit Facility \| Line of Credit
Line of Credit Facility [Line Items]
Credit facility maximum		200,000,000
Line of Credit \| Refinanced Revolving Credit Facility \| Revolving Credit Facility
Line of Credit Facility [Line Items]
Credit facility maximum		$ 160,000,000
Remaining capacity	148,575,000
Line of Credit \| Refinanced Revolving Credit Facility \| Letter of Credit
Line of Credit Facility [Line Items]
Outstanding irrevocable letters of credit totaling	$ 24,525,000

DEBT - Tax-Exempt Financings (Details)	12 Months Ended
DEBT - Tax-Exempt Financings (Details)	Dec. 31, 2019 USD ($)
Unsecured Debt \| New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014 ("New York Bonds 2014") due December 2044 - fixed rate interest period through 2029; bearing interest at 2.875%
Debt Instrument [Line Items]
Aggregate principal amount issued	$ 25,000,000
Aggregate principal amount outstanding	25,000,000
Unsecured Debt \| New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014R-2 ("New York Bonds 2014R-2") due December 2044 - fixed rate interest period through 2026; bearing interest at 3.125%
Debt Instrument [Line Items]
Aggregate principal amount outstanding	15,000,000
Unsecured Debt \| Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2015R-2 due August 2035 - fixed rate interest period through 2025; bearing interest at 4.375%
Debt Instrument [Line Items]
Aggregate principal amount issued	15,000,000
Aggregate principal amount outstanding	$ 15,000,000
Stated interest rate	4.375%
Unsecured Debt \| Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2005R-3 ("FAME Bonds 2005R-3") due January 2025 - fixed rate interest period through 2025; bearing interest at 5.25%
Debt Instrument [Line Items]
Aggregate principal amount outstanding	$ 25,000,000
Stated interest rate	5.25%
Unsecured Debt \| Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2015 (FAME Bonds 2015R-1)
Debt Instrument [Line Items]
Aggregate principal amount outstanding	$ 15,000,000
Stated interest rate	5.125%
Unsecured Debt \| Vermont Economic Development Authority Solid Waste Disposal Revenue Bonds
Debt Instrument [Line Items]
Debt instrument, interest rate during period	4.625%
New York Bonds, 2014R-1
Debt Instrument [Line Items]
Stated interest rate	2.875%
New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014R-2 ("New York Bonds 2014R-2") due December 2044 - fixed rate interest period through 2026; bearing interest at 3.125%
Debt Instrument [Line Items]
Aggregate principal amount outstanding	$ 15,000,000
Stated interest rate	3.125%
Fixed Rate Bonds \| Vermont Bonds
Debt Instrument [Line Items]
Aggregate principal amount issued	$ 16,000,000
Aggregate principal amount outstanding	$ 16,000,000
Stated interest rate	4.75%
New Hampshire Bonds
Debt Instrument [Line Items]
Aggregate principal amount issued	$ 11,000,000
Aggregate principal amount outstanding	$ 11,000,000
Stated interest rate	2.95%

DEBT - Loss on Debt Extinguishment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
Loss on debt extinguishment	$ 0	$ 7,352	$ 517

DEBT - Components of Interest Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
Interest expense on long-term debt and finance leases	$ 22,553	$ 23,431	$ 22,060
Amortization of debt issuance costs and discount on long-term debt	2,293	2,449	2,692
Letter of credit fees	519	554	703
Less: capitalized interest	(263)	(140)	(295)
Total interest expense	$ 25,102	$ 26,294	$ 25,160

DEBT - Cash Flow Hedges (Details) - Interest Rate Contract - Cash Flow Hedging - USD ($)	Feb. 28, 2021	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Notional amount		$ 190,000,000	$ 190,000,000
Weighted average interest rate		2.50%	2.50%
Forecast
Debt Instrument [Line Items]
Notional amount	$ 65,000,000
Weighted average interest rate	1.80%

DEBT - Schedule of Cash Flow Hedges Related to Derivative Instruments on the Balance Sheet (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Cash flow hedge derivatives, assets	$ 0	$ 820
Cash flow hedge derivatives, liabilities	5,427	1,942
Unrealized (loss) gain resulting from changes in fair value of derivative instruments	(4,788)	(1,476)	$ 267
Other current assets \| Designated as hedging instrument \| Interest rate swaps
Debt Instrument [Line Items]
Cash flow hedge derivatives, assets	0	338
Other non-current assets \| Designated as hedging instrument \| Interest rate swaps
Debt Instrument [Line Items]
Cash flow hedge derivatives, assets	0	482
Other accrued liabilities \| Designated as hedging instrument \| Interest rate swaps
Debt Instrument [Line Items]
Cash flow hedge derivatives, liabilities	1,824	387
Other long-term liabilities \| Designated as hedging instrument \| Interest rate swaps
Debt Instrument [Line Items]
Cash flow hedge derivatives, liabilities	3,603	1,555
Accumulated other comprehensive loss, net \| Designated as hedging instrument \| Interest rate swaps
Debt Instrument [Line Items]
Unrealized (loss) gain resulting from changes in fair value of derivative instruments	(5,929)	(1,196)
Accumulated other comprehensive loss, interest rate swaps, tax provision	(112)	(112)
Accumulated other comprehensive loss, interest rate swaps, net	$ (6,041)	$ (1,308)

DEBT - Schedule of Gain (Loss) On Cash Flow Hedges (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Other comprehensive loss, reclassification adjustment from AOCI	$ (553)	$ (363)	$ (421)
Designated as hedging instrument \| Interest rate swaps \| Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Other comprehensive loss, reclassification adjustment from AOCI	$ (553)	$ (363)	$ (421)

DEBT - Fair Value of Debt (Details) $ in Thousands	Dec. 31, 2019 USD ($)
Fair Value \| Fixed Rate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of debt	$ 131,357
Carrying Value \| Fixed Rate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of debt	122,000
Carrying Value \| Secured Debt \| Term Loan Facility
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of debt	350,000
Carrying Value \| Revolving Credit Facility \| Revolving Credit Facility due May 2023 ("Revolving Credit Facility"); bearing interest at LIBOR plus 1.75%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of debt	$ 26,900

DEBT - Schedule of Future Maturities of Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Fiscal year ending December 31, 2020	$ 4,300
Fiscal year ending December 31, 2021	3,593
Fiscal year ending December 31, 2022	5,358
Fiscal year ending December 31, 2023	379,945
Fiscal year ending December 31, 2024	2,893
Thereafter	126,639
Principal amount of debt	$ 522,728	$ 555,249

COMMITMENTS AND CONTINGENCIES - Narrative (Detail) numberOfPlantiffs in Thousands			12 Months Ended
	Sep. 17, 2019 numberOfPlantiffs	Apr. 28, 2017 USD ($)	Dec. 31, 2019 USD ($) executive_officer	Jan. 31, 2020 USD ($)	Apr. 26, 2017 USD ($)	Jan. 29, 2016	Apr. 30, 2011 USD ($)	May 31, 2009 USD ($)	Dec. 20, 2000 a
Other Commitments [Line Items]
Contract extension period			1 year
Number of executive officers \| executive_officer			5
Intangible assets, useful life			10 years
Total annual commitments for salaries			$ 1,937,000
New York Class Litigation
Other Commitments [Line Items]
Number of plaintiffs \| numberOfPlantiffs	1
Notice of Intent to Sue under the Resource Conservation and Recovery Act
Other Commitments [Line Items]
Estimated possible loss					$ 5,000,000
Minimum
Other Commitments [Line Items]
Initial term of employment contract			1 year
Intangible assets, useful life			5 years
Salary and bonuses payment range			1 year
Minimum \| Employment Contracts
Other Commitments [Line Items]
Intangible assets, useful life			1 year
Maximum
Other Commitments [Line Items]
Initial term of employment contract			3 years
Intangible assets, useful life			10 years
Salary and bonuses payment range			3 years
Maximum \| Employment Contracts
Other Commitments [Line Items]
Intangible assets, useful life			2 years
Southbridge Landfill
Other Commitments [Line Items]
Risk free interest rate			1.90%
Potsdam Environmental Remediation Liability
Other Commitments [Line Items]
Risk free interest rate			1.50%
Number of acres composing solid waste transfer station (in acres) \| a									25
Estimate of total undiscounted costs associated with implementing the preferred remedies							$ 12,130,000	$ 10,219,000
Remediation activities, participant share percentage						15.00%
NCES Landfil \| Notice of Intent to Sue for Violations of the CWA \| Subsequent Event
Other Commitments [Line Items]
Estimated possible loss				$ 1,195,000
MADEP \| Notice of Intent to Sue under the Resource Conservation and Recovery Act
Other Commitments [Line Items]
Estimated possible loss					$ 10,000,000
21E Settlement and Water System Construction Funding Agreement \| Bonds
Other Commitments [Line Items]
Facility term		20 years
21E Settlement and Water System Construction Funding Agreement \| Bonds \| Maximum
Other Commitments [Line Items]
Anticipated costs		$ 5,000,000

COMMITMENTS AND CONTINGENCIES - Schedule of Environmental Liability Associated with Southbridge Landfill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Accrual for Environmental Loss Contingencies [Roll Forward]
Ending balance	$ 5,747
Southbridge Landfill
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	5,173	$ 5,936
Accretion expense	124	0
Obligations incurred	0	152
Obligations settled	(701)	(915)
Ending balance	$ 4,596	$ 5,173

COMMITMENTS AND CONTINGENCIES - Schedule of Environmental Liability Associated with Potsdam (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Accrual for Environmental Loss Contingencies [Roll Forward]
Ending balance	$ 5,747
Potsdam Environmental Remediation Liability
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	5,614	$ 5,758
Obligations settled	(4,463)	(171)
Obligations incurred	0	27
Ending balance	$ 1,151	$ 5,614

COMMITMENTS AND CONTINGENCIES - Schedule of Future Minimum Rental (Detail) $ in Thousands	Dec. 31, 2019 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Fiscal year ending December 31, 2020	$ 446
Fiscal year ending December 31, 2021	382
Fiscal year ending December 31, 2022	392
Fiscal year ending December 31, 2023	367
Fiscal year ending December 31, 2024	386
Thereafter	4,630
Total	$ 6,603

COMMITMENTS AND CONTINGENCIES - Reconciliation of Expected Aggregate Non-inflated, Undiscounted Amount to Amount Recognized in Statements of Financial Position (Detail) $ in Thousands	Dec. 31, 2019 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Undiscounted liability	$ 6,603
Less discount, net	(856)
Liability balance	$ 5,747

STOCKHOLDERS' EQUITY - Narrative (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) vote $ / shares shares	Dec. 31, 2018 USD ($) vote shares	Dec. 31, 2017 USD ($)
Limited Partners' Capital Account [Line Items]
Reduction of goodwill	$ 2,619
Preferred stock authorized to issue (up to) (in shares) \| shares	944,000
Shares issued \| shares	0	0
Total fair value of other stock awards vested	$ 8,177	$ 10,529	$ 5,706
Stock Options
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense	0	473	644
Aggregate intrinsic value of stock options exercised	19,475	1,916	4,664
Restricted Stock, Restricted Stock Units and Performance Stock Units
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense	7,036	7,821	5,652
Tax provision (benefit)	(291)
Income tax (benefit) provision associated with stock-based compensation expense		(23)	117
Restricted Stock and Restricted Stock Unit
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense	$ 3,156
Market-based Performance Stock Units
Limited Partners' Capital Account [Line Items]
Weighted average fair value of market-based performance (in dollars per share) \| $ / shares	$ 38.74
Risk-free interest rate	2.28%
Expected volatility	30.90%
Expected dividend yield	0.00%
Amended and Restated 1997 Employee Stock Purchase Plan
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense	$ 186	$ 150	$ 136
Non-Employee Director \| Restricted Stock Awards
Limited Partners' Capital Account [Line Items]
Options vesting period	3 years
Maximum \| Performance Stock Units
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense	$ 6,051
Weighted Average \| Restricted Stock and Restricted Stock Unit
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense, weighted average period	1 year 2 months 12 days
Weighted Average \| Performance Stock Units
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense, weighted average period	1 year 6 months
2016 Incentive Plan
Limited Partners' Capital Account [Line Items]
Options granted period	10 years
2016 Incentive Plan \| Minimum
Limited Partners' Capital Account [Line Items]
Options vesting period	1 year
2016 Incentive Plan \| Maximum
Limited Partners' Capital Account [Line Items]
Options vesting period	4 years
Class A Common Stock
Limited Partners' Capital Account [Line Items]
Vote for each share held (in votes per share) \| vote	1
Number of shares available for future grant \| shares	94,000
Class A Common Stock \| Public Stock Offering
Limited Partners' Capital Account [Line Items]
Sale of stock, number of shares issued \| shares	3,565,000
Sale of stock, price per share (in dollars per share) \| $ / shares	$ 29.50
Sale of stock, net proceeds	$ 100,446
Class A Common Stock \| Unregistered Sale
Limited Partners' Capital Account [Line Items]
Sale of stock, number of shares issued \| shares	59,000
Sale of stock, price per share (in dollars per share) \| $ / shares	$ 44.15
Sale of stock, net proceeds	$ 2,619
Class A Common Stock \| 2016 Incentive Plan
Limited Partners' Capital Account [Line Items]
Common stock, authorized shares \| shares	2,250,000
Common stock, additional authorized shares \| shares	2,723,000
Number of shares available for future grant \| shares	1,361,000
Class B Common Stock
Limited Partners' Capital Account [Line Items]
Vote for each share held (in votes per share) \| vote	10	10

STOCKHOLDERS' EQUITY - Summary of Stock Option Activity (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) $ / shares shares
Stock Options
Outstanding, beginning balance (in shares) \| shares	669,000
Granted (in shares) \| shares	0
Exercised (in shares) \| shares	(571,000)
Forfeited or expired (in shares) \| shares	0
Outstanding, ending balance (in shares) \| shares	98,000
Exercisable (in shares) \| shares	98,000
Weighted Average Exercise Price
Outstanding, beginning balance (in dollars per share) \| $ / shares	$ 6.37
Granted (in dollars per share) \| $ / shares	0
Exercised (in dollars per share) \| $ / shares	5.88
Forfeited or expired (in dollars per share) \| $ / shares	0
Outstanding, ending balance (in dollars per share) \| $ / shares	9.20
Exercisable (in dollars per share) \| $ / shares	$ 9.20
Weighted average remaining contractual term, outstanding	5 years 9 months 18 days
Weighted average remaining contractual term, exercisable	5 years 9 months 18 days
Aggregate intrinsic value, outstanding \| $	$ 3,614
Aggregate intrinsic value, exercisable \| $	$ 3,614

STOCKHOLDERS' EQUITY - Summary of Restricted Stock, Restricted Stock Unit and Performance Stock Unit Activity (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) $ / shares shares
Restricted Stock, Restricted Stock Units and Performance Stock Units
Restricted Stock, Restricted Stock Units, and Performance Stock Units
Outstanding, beginning balance (in shares)	686,000
Granted (in shares)	166,000
Vested (in shares)	(449,000)
Forfeited or canceled (in shares)	(10,000)
Outstanding, ending balance (in shares)	393,000
Unvested, ending balance (in shares)	579,000
Weighted Average Grant Price
Outstanding, beginning balance (in dollars per share) \| $ / shares	$ 15.56
Granted (in dollars per share) \| $ / shares	37.24
Vested (in dollars per share) \| $ / shares	12.38
Forfeited or canceled (in dollars per share) \| $ / shares	23.41
Outstanding, ending balance (in dollars per share) \| $ / shares	28.23
Weighted average grant price, unvested, ending balance (in dollars per share) \| $ / shares	$ 29.69
Weighted average remaining contractual term, outstanding	1 year 3 months 18 days
Weighted average remaining contractual term, unvested	1 year 4 months 24 days
Aggregate intrinsic value, outstanding \| $	$ 6,992
Aggregate intrinsic value, unvested \| $	$ 9,458
Performance Stock Units
Weighted Average Grant Price
Attainment level percentage	100.00%
Class A Common Stock \| Performance Stock Units
Weighted Average Grant Price
Additional issuance if performance targets met (in shares)	186,000
Additional shares issued	178,000

STOCKHOLDERS' EQUITY - Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ (15,832)	$ (37,862)	$ (24,550)
Cumulative effect of new accounting principle				$ 0
Ending balance	122,753	(15,832)	(37,862)
Marketable Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	0	18	(68)
Cumulative effect of new accounting principle				(18)
Other comprehensive income (loss) before reclassifications	0	0	59
Amounts reclassified from accumulated other comprehensive income (loss)	0	0	0
Income tax expense related to items in other comprehensive income (loss)			27
Other comprehensive income (loss), net of tax	0	0	86
Ending balance	0	0	18
Interest Rate Swaps
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(1,308)	166	0
Cumulative effect of new accounting principle				0
Other comprehensive income (loss) before reclassifications	(5,286)	(1,837)	(143)
Amounts reclassified from accumulated other comprehensive income (loss)	553	363	421
Income tax expense related to items in other comprehensive income (loss)			(112)
Other comprehensive income (loss), net of tax	(4,733)	(1,474)	166
Ending balance	(6,041)	(1,308)	166
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(1,308)	184	(68)
Cumulative effect of new accounting principle				$ (18)
Other comprehensive income (loss) before reclassifications	(5,286)	(1,837)	(84)
Amounts reclassified from accumulated other comprehensive income (loss)	553	363	421
Income tax expense related to items in other comprehensive income (loss)			(85)
Other comprehensive income (loss), net of tax	(4,733)	(1,474)	252
Ending balance	$ (6,041)	$ (1,308)	$ 184

STOCKHOLDERS' EQUITY - Reclassification Out of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ (25,102)	$ (26,294)	$ (25,160)
Income (loss) before income taxes	29,779	6,036	(37,052)
Benefit for income taxes	1,874	384	15,253
Net income (loss)	31,653	6,420	(21,799)
Interest Rate Swaps \| Interest rate swaps \| Reclassification out of AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	553	363	421
Income (loss) before income taxes	553	363	421
Benefit for income taxes	0	0	0
Net income (loss)	$ 553	$ 363	$ 421

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

FAIR VALUE OF FINANCIAL INSTRUMENTS (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Assets:
Restricted investment securities - landfill closure	$ 1,586		$ 1,248
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Fair Value, Measurements, Recurring
Assets:
Interest rate swaps		$ 0
Total asset fair value	1,586	1,248
Liabilities:
Interest rate swaps	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Fair Value, Measurements, Recurring \| Landfills
Assets:
Restricted investment securities - landfill closure		1,248
Significant Other Observable Inputs (Level 2) \| Fair Value, Measurements, Recurring
Assets:
Interest rate swaps		820
Total asset fair value	0	820
Liabilities:
Interest rate swaps	5,427	1,942
Significant Other Observable Inputs (Level 2) \| Fair Value, Measurements, Recurring \| Landfills
Assets:
Restricted investment securities - landfill closure		0
Significant Unobservable Inputs (Level 3) \| Fair Value, Measurements, Recurring
Assets:
Interest rate swaps		0
Total asset fair value	0	0
Liabilities:
Interest rate swaps	$ 0	0
Significant Unobservable Inputs (Level 3) \| Fair Value, Measurements, Recurring \| Landfills
Assets:
Restricted investment securities - landfill closure		$ 0

EMPLOYEE BENEFIT PLANS - Narrative (Detail) - USD ($) shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2019
Employee Stock Purchase Plan [Line Items]
Maximum matching contribution per dollar per employee contribution	$ 0.50
Maximum match per employee per calendar year	$ 1,000
Employer contributions vesting period	3 years
Employer contributions	$ 1,608,000	$ 1,319,000	$ 1,817,000
Multiemployer pension plan withdrawal obligation	1,838,000			$ 3,194,000
Withdrawal costs - multiemployer pension plan	3,591,000	$ 0	$ 0
Reversal of pension costs	$ 397,000
Contingent liability term	17 years
Multiemployer pension plan withdrawal obligation, undiscounted	$ 4,224,000
Estimated accumulated benefit obligation as complete withdrawal	$ 18,511,000
Class A Common Stock
Employee Stock Purchase Plan [Line Items]
Discount rate	15.00%
Stock issued under stock purchase plan (in shares)	23	26	41
Stock available for distribution under stock purchase plan (in shares)	94

EMPLOYEE BENEFIT PLANS - Multiemployer Defined Benefit Pension Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Multiemployer Pension Plans \| New England Teamsters and Trucking Industry Pension Fund
Multiemployer Plans [Line Items]
Contributions to Plan	$ 409	$ 726	$ 627

INCOME TAXES - Schedule of Benefit for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Federal
Current	$ (951)	$ (1,902)	$ 0
Deferred	(699)	1,255	(15,614)
Total	(1,650)	(647)	(15,614)
State
Current	321	2,575	301
Current benefit of loss carryforwards	0	(2,307)	(28)
Deferred	(545)	(5)	88
Total	(224)	263	361
Benefit for income taxes	$ (1,874)	$ (384)	$ (15,253)

INCOME TAXES - Narrative (Detail) - USD ($) $ in Thousands	3 Months Ended					12 Months Ended
INCOME TAXES - Narrative (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	May 31, 2019	Jan. 31, 2018
Operating Loss Carryforwards [Line Items]
Deferred income tax benefit						$ (1,244)	$ 1,250	$ (15,525)
Deferred tax liabilities, goodwill									$ 2,385	$ 937
Increase (decrease) in valuation allowance	$ (248)	$ (2,137)	$ 698	$ (1,635)			213	834
Deferred tax (benefit), indefinite lived assets						(297)
Increase in tax provision due to Tax Act								33,700
Increase (decrease) deferred tax benefit related to continuing operations					$ (29,234)			(36,556)
Deferred tax benefit of indefinite lived deferred tax liabilities due to US tax reform					12,758	0	0	12,758
Net deferred tax asset	5,934		7,075			5,934	7,075
Net operating loss carryforwards subject to expiration	110,587					110,587
Net operating loss carryforwards not subject to expiration	67,399					67,399
State net operating loss carryforwards expiry period	101,628					101,628
Alternative minimum tax credit carryforwards	951		1,902			951	1,902
General business tax credit carryforwards	6,273		6,192			6,273	6,192
Deferred tax expense (benefit) due to Tax Cuts and Jobs Act					(15,614)
Unrecognized tax benefit net of federal benefit on state issue			1		2		1	2
Unrecognized tax benefits	0					0
Uncertain tax positions, accrued interest	1		2		3	1	2	3
Uncertain tax positions, penalties	1		1		2	1	1	2
Accrued income tax expense	1		$ 2		$ 3	1	2	$ 3
Federal
Operating Loss Carryforwards [Line Items]
Net deferred tax asset	8,577					8,577
State
Operating Loss Carryforwards [Line Items]
Net deferred tax liability	(2,643)					(2,643)
Goodwill
Operating Loss Carryforwards [Line Items]
Deferred income tax benefit						(2,385)	$ (937)
Complete Disposal Company, Inc
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 1,756					$ 1,756

INCOME TAXES - Schedule of Difference in Benefit for Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Federal statutory rate		21.00%	21.00%	35.00%
Tax at statutory rate		$ 6,254	$ 1,268	$ (12,968)
State income taxes, net of federal benefit		(161)	(89)	(1,959)
Decrease in net federal deferred tax assets before valuation allowance change due to federal rate change		0	0	33,700
Decrease in valuation allowance by 80% of indefinite lived deferred liabilities due to US tax reform	$ (12,758)	0	0	(12,758)
Other changes in valuation allowance, including the federal rate change in fiscal year 2017		(978)	(1,613)	(18,848)
Deductible stock awards		(7,235)	(2,048)	(1,825)
Non-deductible expenses		638	633	542
Non-deductible officer compensation		314	2,214	0
Tax credits		(82)	(686)	(1,000)
Other, net		(624)	(63)	(137)
Benefit for income taxes		$ (1,874)	$ (384)	$ (15,253)

INCOME TAXES - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Net operating loss carryforwards	$ 45,900	$ 31,241
Accrued expenses and reserves	36,342	34,647
General business tax credit carryforwards	6,273	6,192
Book over tax depreciation of property and equipment	2,882	19,048
Unrealized loss on hedges and swaps	1,768	0
Stock awards	1,746	2,310
Alternative minimum tax credit carryforwards	951	1,902
Other	2,576	3,023
Total deferred tax assets	98,438	98,363
Less: valuation allowance	(69,402)	(69,189)
Total deferred tax assets after valuation allowance	29,036	29,174
Deferred tax liabilities:
Amortization of intangibles	(22,910)	(22,026)
Other	(192)	(73)
Total deferred tax liabilities	(23,102)	(22,099)
Net deferred tax asset	$ 5,934	$ 7,075

INCOME TAXES - Schedule of Reconciliation of Gross Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits at beginning of period	$ 2	$ 1,941
Reductions resulting from lapse of statute of limitations	(1)	(1,939)
Unrecognized tax benefits at end of period	$ 1	$ 2

OTHER ITEMS AND CHARGES - Charges Associated with Closure of Southbridge Landfill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Site Contingency [Line Items]
Project development charge	$ 0	$ 311	$ 0
Gain (loss) on contract termination		2,100
Landfill closure project charge	74	16,179	63,526
Southbridge Landfill closure charge, net	2,709	8,054	65,183
Southbridge Landfill
Site Contingency [Line Items]
Asset impairment charge	0	0	47,999
Project development charge	0	0	9,149
Environmental remediation charge	0	0	6,379
Gain (loss) on contract termination	0	8,724	0
Landfill closure project charge	0	6,012	0
Charlton settlement charge	0	1,216	0
Legal and transaction costs	2,709	2,102	1,656
Recovery on insurance settlement	0	(10,000)	0
Southbridge Landfill closure charge, net	$ 2,709	$ 8,054	$ 65,183

OTHER ITEMS AND CHARGES - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Unusual or Infrequent Items, or Both [Abstract]
Expense from acquisition activities	$ 2,687		$ 1,872	$ 176
Contract settlement charges			2,100
Development project charge		$ 0	$ 311	$ 0

EARNINGS PER SHARE (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
EARNINGS PER SHARE (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Numerator:
Net income (loss)									$ 31,653	$ 6,420	$ (21,799)
Denominator:
Shares to be issued - acquisition (in shares)									36,000	103,000	0
Unvested restricted stock (in shares)									0	(9,000)	(38,000)
Effect of weighted average shares outstanding (in shares)									(601,000)	(338,000)	(402,000)
Basic weighted average shares outstanding	47,811,000	47,690,000	47,464,000	45,913,000	42,936,000	42,779,000	42,661,000	42,370,000	47,226,000	42,688,000	41,846,000
Dilutive effect of stock options and stock awards (in shares)									740,000	1,480,000	0
Diluted weighted average shares outstanding	48,583,000	48,361,000	48,221,000	42,913,000	42,936,000	44,175,000	43,916,000	42,370,000	47,966,000	44,168,000	41,846,000
Antidilutive potentially issuable shares (in shares)									2,000	2,000	2,219,000
Class A Common Stock
Denominator:
Common stock, outstanding shares	46,803,000				41,944,000				46,803,000	41,944,000	41,298,000
Class B Common Stock
Denominator:
Common stock, outstanding shares	988,000				988,000				988,000	988,000	988,000

RELATED PARTY TRANSACTIONS (Detail) $ in Thousands	12 Months Ended
RELATED PARTY TRANSACTIONS (Detail) $ in Thousands	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Apr. 30, 1994 Lease
Related Party Transaction [Line Items]
Total services purchased	$ 7,990	$ 3,442	$ 3,398
Outstanding accounts payable	851	32
Number of leases \| Lease				2
Amortization of right-of-use assets	2,122
Accrued costs associated with post-closure obligations	71,927	73,075	62,290
Landfills
Related Party Transaction [Line Items]
Landfill post-closure cost	9	14	27
Accrued costs associated with post-closure obligations	37	48
CCI
Related Party Transaction [Line Items]
Revenue from related party	132	156	237
Related Party
Related Party Transaction [Line Items]
Leases monthly payments	29
Amortization of right-of-use assets	$ 339
Total expense charged to operations under lease agreement		$ 349	$ 360

SEGMENT REPORTING - Summary of Financial Information by Reportable Segment (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenues	$ 193,619	$ 198,547	$ 187,459	$ 163,664	$ 174,724	$ 172,832	$ 165,649	$ 147,455	$ 743,290	$ 660,660	$ 599,309
Depreciation and amortization									79,790	70,508	62,102
Operating income (loss)	14,604	$ 18,485	$ 15,544	$ 4,442	(5,138)	$ 28,884	$ 15,149	$ 838	53,075	39,733	(12,583)
Goodwill	185,819				162,734				185,819	162,734	122,605
Total assets	932,182				732,410				932,182	732,410
Eastern
Segment Reporting Information [Line Items]
Goodwill	30,720				28,154				30,720	28,154	19,192
Western
Segment Reporting Information [Line Items]
Goodwill	141,055				120,536				141,055	120,536	89,369
Recycling
Segment Reporting Information [Line Items]
Goodwill	12,315				12,315				12,315	12,315	12,315
Other
Segment Reporting Information [Line Items]
Goodwill	1,729				1,729				1,729	1,729	1,729
Operating Segments
Segment Reporting Information [Line Items]
Revenues									743,290	660,660	599,309
Depreciation and amortization									79,790	70,508	62,102
Operating income (loss)									53,075	39,733	(12,583)
Interest expense, net									24,735	26,021	24,887
Capital expenditures									103,165	73,232	64,862
Goodwill	185,819				162,734				185,819	162,734	122,605
Total assets	932,182				732,410				932,182	732,410	614,949
Operating Segments \| Eastern
Segment Reporting Information [Line Items]
Revenues									219,475	206,473	181,170
Depreciation and amortization									24,322	26,538	23,815
Operating income (loss)									9,503	4,684	(51,867)
Interest expense, net									218	12	3
Capital expenditures									24,499	23,393	17,153
Goodwill	30,720				28,154				30,720	28,154	19,192
Total assets	207,060				184,679				207,060	184,679	157,248
Operating Segments \| Western
Segment Reporting Information [Line Items]
Revenues									343,399	286,262	250,771
Depreciation and amortization									47,666	35,843	30,766
Operating income (loss)									41,883	41,529	35,035
Interest expense, net									63	(148)	(220)
Capital expenditures									63,540	41,850	42,082
Goodwill	141,054				120,536				141,054	120,536	89,369
Total assets	598,910				428,934				598,910	428,934	344,324
Operating Segments \| Recycling
Segment Reporting Information [Line Items]
Revenues									42,820	42,191	62,307
Depreciation and amortization									4,009	4,345	4,125
Operating income (loss)									(814)	(7,805)	2,805
Interest expense, net									160	140	143
Capital expenditures									9,719	4,476	2,006
Goodwill	12,316				12,315				12,316	12,315	12,315
Total assets	56,688				48,629				56,688	48,629	48,612
Operating Segments \| Other
Segment Reporting Information [Line Items]
Revenues									137,596	125,734	105,061
Depreciation and amortization									3,793	3,782	3,396
Operating income (loss)									2,503	1,325	1,444
Interest expense, net									24,294	26,017	24,961
Capital expenditures									5,407	3,513	3,621
Goodwill	1,729				1,729				1,729	1,729	1,729
Total assets	$ 69,524				$ 70,168				69,524	70,168	64,765
Eliminations
Segment Reporting Information [Line Items]
Revenues									(163,920)	(142,789)	(123,972)
Interest expense, net											0
Eliminations \| Eastern
Segment Reporting Information [Line Items]
Revenues									(54,738)	(52,866)	(50,335)
Eliminations \| Western
Segment Reporting Information [Line Items]
Revenues									(97,339)	(81,515)	(71,510)
Eliminations \| Recycling
Segment Reporting Information [Line Items]
Revenues									(9,400)	(6,426)	(246)
Eliminations \| Other
Segment Reporting Information [Line Items]
Revenues									$ (2,443)	$ (1,982)	$ (1,881)

SEGMENT REPORTING - Summary of Revenue Attributable to Services Provided by Company (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue from External Customer [Line Items]
Revenues	$ 193,619	$ 198,547	$ 187,459	$ 163,664	$ 174,724	$ 172,832	$ 165,649	$ 147,455	$ 743,290	$ 660,660	$ 599,309
Revenues percentage									100.00%	100.00%	100.00%
Collection
Revenue from External Customer [Line Items]
Revenues									$ 372,041	$ 303,418	$ 263,688
Revenues percentage									50.10%	45.90%	44.00%
Disposal
Revenue from External Customer [Line Items]
Revenues									$ 181,895	$ 181,110	$ 160,073
Revenues percentage									24.50%	27.40%	26.70%
Power generation
Revenue from External Customer [Line Items]
Revenues									$ 3,576	$ 5,129	$ 5,375
Revenues percentage									0.50%	0.80%	0.90%
Processing
Revenue from External Customer [Line Items]
Revenues									$ 7,175	$ 7,174	$ 7,994
Revenues percentage									0.90%	1.10%	1.30%
Solid waste operations
Revenue from External Customer [Line Items]
Revenues									$ 564,687	$ 496,831	$ 437,130
Revenues percentage									76.00%	75.20%	72.90%
Organics
Revenue from External Customer [Line Items]
Revenues									$ 56,326	$ 54,174	$ 39,815
Revenues percentage									7.50%	8.20%	6.60%
Customer solutions
Revenue from External Customer [Line Items]
Revenues									$ 79,457	$ 67,464	$ 60,057
Revenues percentage									10.70%	10.20%	10.10%
Recycling
Revenue from External Customer [Line Items]
Revenues									$ 42,820	$ 42,191	$ 62,307
Revenues percentage									5.80%	6.40%	10.40%

QUARTERLY FINANCIAL INFORMATION (UNAUDITED) (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 193,619	$ 198,547	$ 187,459	$ 163,664	$ 174,724	$ 172,832	$ 165,649	$ 147,455	$ 743,290	$ 660,660	$ 599,309
Operating income	14,604	18,485	15,544	4,442	(5,138)	28,884	15,149	838	$ 53,075	$ 39,733	$ (12,583)
Net (loss) income	$ 9,066	$ 12,386	$ 11,915	$ (1,714)	$ (13,676)	$ 22,302	$ 1,704	$ (3,910)
Earnings per common share:
Basic weighted average shares outstanding	47,811	47,690	47,464	45,913	42,936	42,779	42,661	42,370	47,226	42,688	41,846
Basic earnings (loss) per common share (in dollars per share)	$ 0.19	$ 0.26	$ 0.25	$ (0.04)	$ (0.32)	$ 0.52	$ 0.04	$ (0.09)	$ 0.67	$ 0.15	$ (0.52)
Diluted weighted average shares outstanding	48,583	48,361	48,221	42,913	42,936	44,175	43,916	42,370	47,966	44,168	41,846
Diluted earnings (loss) per common share (in dollars per share)	$ 0.19	$ 0.26	$ 0.25	$ (0.04)	$ (0.32)	$ 0.50	$ 0.04	$ (0.09)	$ 0.66	$ 0.15	$ (0.52)

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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- Definition

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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+ Details

Schedule II - Valuation Accounts (Detail) - Allowance for Credit Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	$ 931	$ 809	$ 1,069
Additions—charged to expense	1,360	1,620	290
Deductions—bad debts written off, net of recoveries	(823)	(1,498)	(550)
Balance at end of period	$ 1,468	$ 931	$ 809

Label	Element	Value
Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 18,000

REVENUE RECOGNITION (Details) - USD ($) $ in Thousands	12 Months Ended
REVENUE RECOGNITION (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	$ 743,290	$ 660,660	$ 599,309
Eastern
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	219,475	206,473
Western
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	343,399	286,262
Recycling
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	42,820	42,191
Other
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	137,596	125,734
Collection
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	377,839	306,939
Collection \| Eastern
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	154,805	136,661
Collection \| Western
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	223,034	170,278
Collection \| Recycling
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	0	0
Collection \| Other
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	0	0
Landfill
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	93,019	94,986
Landfill \| Eastern
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	19,362	28,419
Landfill \| Western
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	73,657	66,567
Landfill \| Recycling
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	0	0
Landfill \| Other
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	0	0
Transfer
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	76,138	67,583
Transfer \| Eastern
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	44,413	39,991
Transfer \| Western
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	31,725	27,592
Transfer \| Recycling
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	0	0
Transfer \| Other
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	0	0
Customer solutions
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	79,457	67,464
Customer solutions \| Eastern
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	0	0
Customer solutions \| Western
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	0	0
Customer solutions \| Recycling
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	0	0
Customer solutions \| Other
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	79,457	67,464
Recycling
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	44,311	46,019
Recycling \| Eastern
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	5	5
Recycling \| Western
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	1,486	3,823
Recycling \| Recycling
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	42,820	42,191
Recycling \| Other
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	0	0
Organics
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	56,326	54,174
Organics \| Eastern
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	0	0
Organics \| Western
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	0	0
Organics \| Recycling
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	0	0
Organics \| Other
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	56,326	54,174
Transportation
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	12,624	18,366
Transportation \| Eastern
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	0	0
Transportation \| Western
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	10,811	14,270
Transportation \| Recycling
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	0	0
Transportation \| Other
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	1,813	4,096
Landfill gas-to-energy
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	3,576	5,129
Landfill gas-to-energy \| Eastern
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	890	1,397
Landfill gas-to-energy \| Western
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	2,686	3,732
Landfill gas-to-energy \| Recycling
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	0	0
Landfill gas-to-energy \| Other
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	0	0
Transferred at a point-in-time
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	24,286	32,974
Transferred at a point-in-time \| Eastern
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	159	648
Transferred at a point-in-time \| Western
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	921	1,145
Transferred at a point-in-time \| Recycling
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	19,738	27,260
Transferred at a point-in-time \| Other
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	3,468	3,921
Transferred over time
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	719,004	627,686
Transferred over time \| Eastern
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	219,316	205,825
Transferred over time \| Western
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	342,478	285,117
Transferred over time \| Recycling
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	23,082	14,931
Transferred over time \| Other
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	$ 134,128	$ 121,813