Casella Waste Systems (CWST) 10-Q 28 Apr 23 2023 Q1 Quarterly report Financial data

COVER

COVER - shares	3 Months Ended
	Mar. 31, 2023	Apr. 15, 2023
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2023
Document Transition Report	false
Entity File Number	000-23211
Entity Registrant Name	CASELLA WASTE SYSTEMS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	03-0338873
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
Title of 12(b) Security	Class A common stock, $0.01 par value per share
Trading Symbol	CWST
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Central Index Key	0000911177
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q1
Amendment Flag	false
Class A Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		50,897,927
Class B Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		988,200

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
CURRENT ASSETS:
Cash and cash equivalents	$ 60,226	$ 71,152
Accounts receivable, net of allowance for credit losses of $3,590 and $3,016, respectively	95,192	100,886
Prepaid expenses	11,627	15,182
Inventory	14,175	13,472
Other current assets	6,608	6,787
Total current assets	187,828	207,479
Property, plant and equipment, net of accumulated depreciation and amortization of $1,090,951 and $1,064,756, respectively	711,440	720,550
Operating lease right-of-use assets	95,406	92,063
Goodwill	274,458	274,458
Intangible assets, net	87,712	91,783
Restricted assets	1,972	1,900
Cost method investments	10,967	10,967
Deferred income taxes	23,491	22,903
Other non-current assets	26,616	27,112
Total assets	1,419,890	1,449,215
CURRENT LIABILITIES:
Current maturities of debt	9,274	8,968
Current operating lease liabilities	7,190	7,000
Accounts payable	66,640	74,203
Accrued payroll and related expenses	8,484	23,556
Accrued interest	3,442	2,858
Contract liabilities	4,146	3,742
Current accrued final capping, closure and post-closure costs	10,991	11,036
Other accrued liabilities	34,955	46,237
Total current liabilities	145,122	177,600
Debt, less current portion	577,567	585,015
Operating lease liabilities, less current portion	62,155	57,345
Accrued final capping, closure and post-closure costs, less current portion	105,165	102,642
Deferred income taxes	438	437
Other long-term liabilities	27,788	28,276
COMMITMENTS AND CONTINGENCIES
STOCKHOLDERS' EQUITY:
Additional paid-in capital	663,735	661,761
Accumulated deficit	(168,372)	(171,920)
Accumulated other comprehensive income, net of tax	5,773	7,542
Total stockholders' equity	501,655	497,900
Total liabilities and stockholders' equity	1,419,890	1,449,215
Class A Common Stock
STOCKHOLDERS' EQUITY:
Common stock	509	507
Class B Common Stock
STOCKHOLDERS' EQUITY:
Common stock	$ 10	$ 10

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2023 USD ($) vote $ / shares shares	Dec. 31, 2022 USD ($) vote $ / shares shares
Accounts receivable - trade, allowance for credit losses | $	$ 3,590	$ 3,016
Accumulated depreciation and amortization | $	$ 1,090,951	$ 1,064,756
Class A Common Stock
Common stock, par value (in dollars per share) | $ / shares	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	50,898,000	50,704,000
Common stock, shares outstanding (in shares)	50,898,000	50,704,000
Class B Common Stock
Common stock, par value (in dollars per share) | $ / shares	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	1,000,000	1,000,000
Common stock, shares issued (in shares)	988,000	988,000
Common stock, shares outstanding (in shares)	988,000	988,000
Votes per share held (in votes) | vote	10	10

UNAUDITED CONSOLIDATED STATEMEN

UNAUDITED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Income Statement [Abstract]
Revenues	$ 262,595	$ 234,027
Operating expenses:
Cost of operations	180,243	162,455
General and administration	35,679	29,793
Depreciation and amortization	33,435	29,428
Expense from acquisition activities	2,863	2,043
Southbridge Landfill closure charge	110	140
Total operating expenses	252,330	223,859
Operating income	10,265	10,168
Other expense (income):
Interest income	(684)	(40)
Interest expense	6,959	5,204
Other income	(349)	(144)
Other expense, net	5,926	5,020
Income before income taxes	4,339	5,148
Provision for income taxes	791	958
Net income	$ 3,548	$ 4,190
Basic earnings per share attributable to common stockholders:
Weighted average common shares outstanding, basic (in shares)	51,770	51,490
Basic earnings per common share (in dollars per share)	$ 0.07	$ 0.08
Diluted earnings per share attributable to common stockholders:
Weighted average common shares outstanding, diluted (in shares)	51,869	51,657
Diluted earnings per common share (in dollars per share)	$ 0.07	$ 0.08

UNAUDITED CONSOLIDATED STATEM_2

UNAUDITED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 3,548	$ 4,190
Hedging activity:
Interest rate swap settlements	1,055	(1,163)
Interest rate swap amounts reclassified into interest expense	(1,106)	1,128
Unrealized (loss) gain resulting from changes in fair value of derivative instruments	(2,391)	8,381
Other comprehensive (loss) income, before tax	(2,442)	8,346
Income tax (benefit) provision related to items of other comprehensive (loss) income	(673)	2,203
Other comprehensive (loss) income, net of tax	(1,769)	6,143
Comprehensive income	$ 1,779	$ 10,333

UNAUDITED CONSOLIDATED STATEM_3

UNAUDITED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Additional Paid-In Capital	Accumulated Deficit	Accumulated other comprehensive income, net of tax	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, 2021	$ 422,457	$ 652,045	$ (224,999)	$ (5,103)		$ 504		$ 10
Beginning balance (in shares) at Dec. 31, 2021						50,423,000		988,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances of Class A common stock	19	17				$ 2
Issuance of Class A common stock (in shares)						227,000
Stock-based compensation	2,241	2,241
Net income (loss)	4,190		4,190
Hedging activity	6,143			6,143
Ending balance at Mar. 31, 2022	435,050	654,303	(220,809)	1,040		$ 506		$ 10
Ending balance (in shares) at Mar. 31, 2022					50,650,000	50,650,000	988,000	988,000
Beginning balance at Dec. 31, 2022	497,900	661,761	(171,920)	7,542		$ 507		$ 10
Beginning balance (in shares) at Dec. 31, 2022					50,704,000	50,704,000	988,000	988,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances of Class A common stock	0	(2)				$ 2
Issuance of Class A common stock (in shares)						194,000
Stock-based compensation	1,976	1,976
Net income (loss)	3,548		3,548
Hedging activity	(1,769)			(1,769)
Ending balance at Mar. 31, 2023	$ 501,655	$ 663,735	$ (168,372)	$ 5,773		$ 509		$ 10
Ending balance (in shares) at Mar. 31, 2023					50,898,000	50,898,000	988,000	988,000

UNAUDITED CONSOLIDATED STATEM_4

UNAUDITED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Cash Flows from Operating Activities:
Net income	$ 3,548	$ 4,190
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	33,435	29,428
Interest accretion on landfill and environmental remediation liabilities	2,510	1,966
Amortization of debt issuance costs	502	457
Stock-based compensation	1,976	2,241
Operating lease right-of-use assets expense	3,328	3,162
Disposition of assets, other items and charges, net	1,315	860
Deferred income taxes	86	534
Changes in assets and liabilities, net of effects of acquisitions and divestitures:
Accounts receivable	5,694	402
Accounts payable	(7,563)	2,116
Prepaid expenses, inventories and other assets	1,701	(1,060)
Accrued expenses, contract liabilities and other liabilities	(30,453)	(19,582)
Net cash provided by operating activities	16,079	24,714
Cash Flows from Investing Activities:
Acquisitions, net of cash acquired	(263)	(49,757)
Additions to property, plant and equipment	(17,879)	(12,910)
Proceeds from sale of property and equipment	415	145
Net cash used in investing activities	(17,727)	(62,522)
Cash Flows from Financing Activities:
Proceeds from debt borrowings	0	25,600
Principal payments on debt	(8,996)	(9,014)
Payments of debt issuance costs	(282)	(12)
Proceeds from the exercise of share based awards	0	19
Net cash (used in) provided by financing activities	(9,278)	16,593
Net decrease in cash and cash equivalents	(10,926)	(21,215)
Cash and cash equivalents, beginning of period	71,152	33,809
Cash and cash equivalents, end of period	60,226	12,594
Supplemental Disclosure of Cash Flow Information:
Cash interest payments	5,873	4,840
Cash income tax payments	4,807	221
Right-of-use assets obtained in exchange for new finance lease liabilities	1,634	1,032
Right-of-use assets obtained in exchange for operating lease obligations	$ 5,682	$ 2,710

BASIS OF PRESENTATION

BASIS OF PRESENTATION	3 Months Ended
	Mar. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
BASIS OF PRESENTATION	BASIS OF PRESENTATION Casella Waste Systems, Inc. (“Parent”), a Delaware corporation, and its consolidated subsidiaries (collectively, “we”, “us” or “our”), is a regional, vertically integrated solid waste services company. We provide resource management expertise and services to residential, commercial, municipal, institutional and industrial customers, primarily in the areas of solid waste collection and disposal, transfer, recycling and organics services. We provide integrated solid waste services in seven states: Vermont, New Hampshire, New York, Massachusetts, Connecticut, Maine and Pennsylvania, with our headquarters located in Rutland, Vermont. We manage our solid waste operations on a geographic basis through two regional operating segments, the Eastern and Western regions, each of which provides a full range of solid waste services. We manage our resource-renewal operations through the Resource Solutions operating segment, which leverages our core competencies in materials processing, industrial recycling, organics and resource management service offerings to deliver a comprehensive solution for our larger commercial, municipal, institutional and industrial customers that have more diverse waste and recycling needs. Legal, tax, information technology, human resources, certain finance and accounting and other administrative functions are included in our Corporate Entities segment. The accompanying unaudited consolidated financial statements, which include the accounts of the Parent and our wholly-owned subsidiaries, 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. Our significant accounting policies are more fully discussed in Item 8. " Financial Statements and Supplementary Data " of our Annual Report on Form 10-K for the fiscal year ended December 31, 2022 ("fiscal year 2022"), which was filed with the SEC on February 17, 2023 ("2022 Form 10-K"). 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 the opinion of management, these consolidated financial statements include all adjustments, which include normal recurring and nonrecurring adjustments, necessary for a fair presentation of the financial position, results of operations and cash flows for the periods presented. The results for the three months ended March 31, 2023 may not be indicative of the results for any other interim period or the entire fiscal year. The consolidated financial statements presented herein should be read in conjunction with our audited consolidated financial statements included in our 2022 Form 10-K. When necessary, certain prior period amounts in the consolidated financial statements are conformed to current period presentation. This includes the presentation of certain adjustments to reconcile net income to net cash provided by operating activities, which have been reclassified within cash flows from operating activities. Subsequent Events We have evaluated subsequent events or transactions that have occurred after the consolidated balance sheet date of March 31, 2023 through the date of filing of the consolidated financial statements with the SEC on this Quarterly Report on Form 10-Q. Except as disclosed, no material subsequent events have occurred since March 31, 2023 through the date of this filing that would require recognition or disclosure in our consolidated financial statements.

ACCOUNTING CHANGES

ACCOUNTING CHANGES	3 Months Ended
	Mar. 31, 2023
Accounting Changes and Error Corrections [Abstract]
ACCOUNTING CHANGES	ACCOUNTING CHANGES The following table provides a brief description of a recent Accounting Standards Update ("ASU(s)") to the Accounting Standards Codification ("ASC") issued by the Financial Accounting Standards Board (“FASB”) that we adopted and is deemed to have a possible material impact on our consolidated financial statements based on current account balances and activity: Standard Description Effect on the Financial Statements or Other Accounting standards adopted effective January 1, 2023 ASU No. 2020-04: Reference Rate Reform (Topic 848), as amended through December 2022 Provides temporary optional guidance to ease the potential burden in applying GAAP to contract modifications and hedging relationships that reference London Inter-Bank Offered Rate ("LIBOR") or another reference rate expected to be discontinued, subject to meeting certain criteria. We currently have interest rate derivative agreements with hedging relationships that reference LIBOR, which is going to be discontinued effective July 1, 2023. This guidance provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions affected by reference rate reform if certain criteria are met. Effective the three months ended March 31, 2023, we elected optional expedients under this guidance that provide temporary relief over contract modifications and hedge accounting in order to maintain hedge effectiveness upon modifying contract terms related to reference rate reform in our amended and restated credit agreement, dated as of December 22, 2021, as amended by the first amendment, dated as of February 9, 2023, and the second amendment, dated as of February 9, 2023 (the "Amended and Restated Credit Agreement") and to transition our interest rate derivative agreements from LIBOR to another reference rate prior to the planned discontinuation of LIBOR on July 1, 2023. See Note 7, Debt. This guidance will be in effect through December 31, 2024.

REVENUE RECOGNITION

REVENUE RECOGNITION	3 Months Ended
	Mar. 31, 2023
Revenue from Contract with Customer [Abstract]
REVENUE RECOGNITION	REVENUE RECOGNITIONRevenues associated with our solid waste operations are derived mainly from solid waste collection and disposal services, including landfill, transfer station and transportation services, landfill gas-to-energy services and processing services. Revenues associated with our resource-renewal operations are derived from processing services, and non-processing services, which we now refer to as our National Accounts business. The following tables set forth revenues disaggregated by service line and timing of revenue recognition by operating segment for each of the three months ended March 31, 2023 and 2022: Three Months Ended March 31, 2023 Eastern Western Resource Solutions Total Revenues Collection $ 61,108 $ 78,869 $ — $ 139,977 Landfill 6,301 16,460 — 22,761 Transfer station 13,981 9,961 — 23,942 Transportation 1,183 3,580 — 4,763 Landfill gas-to-energy 213 1,711 — 1,924 Processing 1,123 453 22,806 24,382 National Accounts — — 44,846 44,846 Total revenues $ 83,909 $ 111,034 $ 67,652 $ 262,595 Transferred at a point-in-time $ 119 $ 731 $ 6,438 $ 7,288 Transferred over time 83,790 110,303 61,214 255,307 Total revenues $ 83,909 $ 111,034 $ 67,652 $ 262,595 Three Months Ended March 31, 2022 Eastern Western Resource Solutions Total Revenues Collection $ 51,497 $ 68,034 $ — $ 119,531 Landfill 5,376 14,190 — 19,566 Transfer station 11,613 7,844 — 19,457 Transportation 1,472 2,658 — 4,130 Landfill gas-to-energy 274 2,380 — 2,654 Processing 1,087 733 27,395 29,215 National Accounts — — 39,474 39,474 Total revenues $ 71,319 $ 95,839 $ 66,869 $ 234,027 Transferred at a point-in-time $ 120 $ 511 $ 15,086 $ 15,717 Transferred over time 71,199 95,328 51,783 218,310 Total revenues $ 71,319 $ 95,839 $ 66,869 $ 234,027 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 $6,629 in the three months ended March 31, 2023 and $3,794 in the three months ended March 31, 2022. 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. We did not record any revenues in the three months ended March 31, 2023 or March 31, 2022 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 $97,340 and $102,234 as of March 31, 2023 and December 31, 2022, 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. We recognized contract liabilities of $4,146 and $3,742 as of March 31, 2023 and December 31, 2022, respectively. Due to the short term nature of advanced billings, substantially all of the deferred revenue recognized as a contract liability as of December 31, 2022 and December 31, 2021 was recognized as revenue during the three months ended March 31, 2023 and March 31, 2022, respectively, when the services were performed.

INTANGIBLE ASSETS

INTANGIBLE ASSETS	3 Months Ended
	Mar. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
INTANGIBLE ASSETS	INTANGIBLE ASSETS Summaries of intangible assets by type follows: Covenants Customer Relationships Trade Names Total Balance, March 31, 2023 Intangible assets $ 31,201 $ 127,179 $ 8,405 $ 166,785 Less accumulated amortization (24,593) (49,172) (5,308) (79,073) $ 6,608 $ 78,007 $ 3,097 $ 87,712 Covenants Customer Relationships Trade Names Total Balance, December 31, 2022 Intangible assets $ 31,201 $ 127,179 $ 8,405 $ 166,785 Less accumulated amortization (24,129) (46,162) (4,711) (75,002) $ 7,072 $ 81,017 $ 3,694 $ 91,783 Intangible amortization expense was $4,071 during the three months ended March 31, 2023 and $3,789 during the three months ended March 31, 2022. A summary of intangible amortization expense estimated for each of the next five fiscal years following fiscal year 2022 and thereafter is estimated as follows: Estimated Future Amortization Expense as of March 31, 2023 Fiscal year ending December 31, 2023 $ 12,071 Fiscal year ending December 31, 2024 $ 15,471 Fiscal year ending December 31, 2025 $ 14,429 Fiscal year ending December 31, 2026 $ 12,745 Fiscal year ending December 31, 2027 $ 11,266 Thereafter $ 21,730

OTHER ACCRUED LIABILITIES

OTHER ACCRUED LIABILITIES	3 Months Ended
	Mar. 31, 2023
Payables and Accruals [Abstract]
OTHER ACCRUED LIABILITIES	OTHER ACCRUED LIABILITIES A summary of other accrued liabilities, classified as current liabilities follows: March 31, December 31, Self insurance reserve - current portion $ 7,691 $ 7,422 Accrued capital expenditures 4,000 10,842 Other accrued liabilities 23,264 27,973 Total $ 34,955 $ 46,237

ACCRUED FINAL CAPPING, CLOSURE

ACCRUED FINAL CAPPING, CLOSURE AND POST CLOSURE	3 Months Ended
	Mar. 31, 2023
Asset Retirement Obligation Disclosure [Abstract]
ACCRUED FINAL CAPPING, CLOSURE AND POST CLOSURE	ACCRUED FINAL CAPPING, CLOSURE AND POST CLOSURE Accrued 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. 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. A summary of the changes to accrued final capping, closure and post-closure liabilities follows: Three Months Ended 2023 2022 Beginning balance $ 113,678 $ 86,914 Obligations incurred 1,247 966 Accretion expense 2,410 1,873 Obligations settled (1) (1,179) (926) Ending balance $ 116,156 $ 88,827 (1) May include amounts that are being processed through accounts payable as a part of our disbursements cycle.

DEBT

DEBT	3 Months Ended
	Mar. 31, 2023
Debt And Derivatives Disclosure [Abstract]
DEBT	DEBT A summary of debt is as follows: March 31, December 31, Senior Secured Credit Facility: Term loan A facility ("Term Loan Facility") due December 2026; bearing interest at term secured overnight financing rate ("Term SOFR") plus 1.135% $ 350,000 $ 350,000 Revolving credit facility ("Revolving Credit Facility") due December 2026; bearing interest at Term SOFR plus 1.135% — 6,000 Tax-Exempt Bonds: New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014 ("New York Bonds 2014R-1") 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 New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2020 ("New York Bonds 2020") due September 2050 - fixed rate interest period through 2025; bearing interest at 2.750% 40,000 40,000 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 2013") due April 2036 - fixed rate interest period through 2028; bearing interest at 4.625% 16,000 16,000 Vermont Economic Development Authority Solid Waste Disposal Long-Term Revenue Bonds Series 2022A-1 ("Vermont Bonds 2022A-1") due June 2052 - fixed rate interest period through 2027; bearing interest at 5.00% 35,000 35,000 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 48,800 49,813 Notes payable maturing through August 2024; bearing interest up to 4.0% 316 664 Principal amount of debt 596,116 603,477 Less—unamortized debt issuance costs (1) 9,275 9,494 Debt less unamortized debt issuance costs 586,841 593,983 Less—current maturities of debt 9,274 8,968 $ 577,567 $ 585,015 (1) A summary of unamortized debt issuance costs by debt instrument follows: March 31, December 31, Revolving Credit Facility and Term Loan Facility (collectively, the "Credit Facility") $ 4,692 $ 4,716 New York Bonds 2014R-1 849 866 New York Bonds 2014R-2 192 207 New York Bonds 2020 1,061 1,106 FAME Bonds 2005R-3 155 176 FAME Bonds 2015R-1 326 344 FAME Bonds 2015R-2 175 193 Vermont Bonds 2013 365 378 Vermont Bonds 2022A-1 1,111 1,144 New Hampshire Bonds 349 364 $ 9,275 $ 9,494 Financing Activities In April 2023, we entered into a commitment letter with lenders to obtain secured bridge financing in an amount of up to $375,000, less the amount of any term loan A ("Term Loan A"), and received the commitment of certain commitment parties to fund up to $261,500 of a maximum of $400,000 Term Loan A, which may be a delayed draw, under our Amended and Restated Credit Agreement to fund, in conjunction with cash and cash equivalents and borrowings from our Revolving Credit Facility the purchase of the equity interests of four wholly owned subsidiaries of GFL Environmental ("GFL Subsidiaries"). On April 21, 2023, we entered into an equity purchase agreement with GFL Environmental Inc. to purchase 100% of the equity interests of the GFL Subsidiaries that operate solid waste collection, transfer and recycling operations in Pennsylvania, Maryland, and Delaware for approximately $525,000 in cash. The proposed acquisition includes nine hauling operations, one transfer station, and one material recovery facility. The acquisition is expected to close by the third quarter of the fiscal year ending December 31, 2023 ("fiscal year 2023"), subject to customary closing conditions, including regulatory approvals. Credit Facility As of March 31, 2023, we are party to the Amended and Restated Credit Agreement, which provides for a $350,000 aggregate principal amount Term Loan Facility and a $300,000 Revolving Credit Facility, with a $75,000 sublimit for letters of credit. We have the right to request, at our discretion, an increase in the amount of loans under the Credit Facility by an aggregate amount of $125,000, subject to the terms and conditions set forth in the Amended and Restated Credit Agreement. The Credit Facility has a 5-year term that matures in December 2026. On February 9, 2023, we entered into first and second amendments to the Amended and Restated Credit Agreement. The first amendment provides, commencing in the fiscal year ending December 31, 2024, the interest rate margin applied for drawn and undrawn amounts under the Amended and Restated Credit Agreement shall be separately adjusted based on our achievement of certain thresholds and targets on two sustainability related key performance indicator metrics during fiscal year 2023: (i) metric tons of solid waste materials reduced, reused or recycled through our direct operations or with third-parties in collaboration with customers; and (ii) our total recordable incident rate. The second amendment provides that loans under the Amended and Restated Credit Agreement shall bear interest, at our election, at Term SOFR, including a secured overnight financing rate adjustment of 10 basis points, or at a base rate, in each case, plus an applicable interest rate margin based on consolidated net leverage ratio, and plus or minus any sustainability rate adjustment. Unless loans are made as or converted to base rate loans, loans under the Amended and Restated Credit Agreement will bear interest at Term SOFR, including a secured overnight financing rate adjustment of 10 basis points, plus a margin based upon our consolidated net leverage ratio in the range of 1.125% to 2.125% per annum, plus a sustainability adjustment of up to positive or negative 4.0 basis point per annum. A commitment fee will be charged on undrawn amounts at a rate of Term SOFR, plus a margin based upon our consolidated net leverage ratio in the range of 0.20% to 0.40% per annum, plus a sustainability adjustment of up to positive or negative 1.0 basis points per annum. We are also required to pay a fronting fee for each letter of credit of 0.25% per annum. Interest under the Amended and Restated Credit Agreement is subject to increase by 2.00% per annum during the continuance of a payment default and may be subject to increase by 2.00% per annum during the continuance of any other event of default. 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 March 31, 2023, further advances were available under the Revolving Credit Facility in the amount of $272,267. The available amount is net of outstanding irrevocable letters of credit totaling $27,733, and as of March 31, 2023 no amount had been drawn. 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 have designated these derivative instruments as highly effective cash flow hedges, and therefore the change in their fair value is recorded in stockholders’ equity as a component of accumulated other comprehensive income, net of tax 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. As of both March 31, 2023 and December 31, 2022, our active interest rate derivative agreements had a total notional amount of $190,000. According to the terms of the agreements, we receive interest based on the 1-month LIBOR index, in some instances restricted by a 0.0% floor, and pay interest at a weighted average rate of approximately 2.20%. The agreements mature between May 2023 and June 2027. As of March 31, 2023, we had outstanding forward starting interest rate derivative agreements with a total notional amount of $60,000, $20,000 of which we will receive interest based on the 1-month LIBOR index, restricted by a 0.0% floor, and $40,000 of which we will receive interest based on Term SOFR, restricted by a 0.0% floor. The agreements mature in May 2028 and will pay interest at a weighted average interest rate of 2.8%. As of December 31, 2022, we had a forward starting interest rate derivative agreement with a notional amount of $20,000. A summary of the effect of cash flow hedges related to derivative instruments on the consolidated balance sheet follows: Fair Value Balance Sheet Location March 31, December 31, Interest rate swaps Other current assets $ 4,388 $ 4,345 Interest rate swaps Other non-current assets 5,712 7,461 $ 10,100 $ 11,806 Interest rate swaps Other long-term liabilities $ 736 $ — Interest rate swaps Accumulated other comprehensive income, net of tax $ 9,364 $ 11,806 Interest rate swaps - tax effect Accumulated other comprehensive income, net of tax (3,591) (4,264) $ 5,773 $ 7,542

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Legal Proceedings 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. The plaintiffs in some actions seek unspecified damages or injunctive relief, or both. These actions fall within various procedural stages at any point in time, and some are covered in part by insurance. In accordance with FASB ASC 450 - Contingencies, we accrue for legal proceedings, inclusive of legal costs, when losses become probable and reasonably estimable. We have recorded an aggregate accrual of $821 relating to our outstanding legal proceedings as of March 31, 2023. 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. We disclose outstanding matters that we believe could have a material adverse effect on our financial condition, results of operations or cash flows. North Country Environmental Services Expansion Permit On October 9, 2020, our subsidiary, North Country Environmental Services, Inc. ("NCES"), received a Type I-A Permit Modification ("Permit") from the New Hampshire Department of Environmental Services ("DES") for Expansion in the Stage VI area of the NCES landfill located in Bethlehem, New Hampshire. On November 9, 2020, the Conservation Law Foundation ("CLF") filed an appeal of the Permit to the New Hampshire Waste Management Council (“Council”) on the grounds it failed to meet the public benefit criteria. DES defended its decision in the appeal, and NCES also participated as the permittee seeking to defend its permit on appeal. Throughout 2021 and early 2022 a number of motions were filed by both NCES and CLF with the Council and in February 2022 the Council held a hearing on the CLF appeal. The Council ruled in favor of NCES on all claims set forth in CLF’s appeal. On May 11, 2022, the Council’s Hearing Officer issued an Order denying all of CLF’s arguments on appeal, with the exception of one: the Hearing Officer held that based on his interpretation of the relevant statute, the public benefit determination made by DES in issuing the Permit to NCES was unlawful (the “Hearing Officer’s Order”). The Hearing Officer remanded the Permit to DES with regard to this determination. DES filed a Motion for Reconsideration on May 31, 2022, and NCES filed a Motion for Rehearing on June 10, 2022. The Hearing Officer denied both motions in separate orders dated November 3, 2022, issued contemporaneously with rulings on three other post-hearing motions. NCES filed a Motion for Rehearing of two of the three post-hearing motion rulings on December 5, 2023, and this Motion remains pending. DES and NCES appealed the Hearing Officer’s Order to the New Hampshire Supreme Court (“Supreme Court”). On December 23, 2022, CLF filed a Motion for Summary Affirmance of the Hearing Officer’s Order, to which NCES and DES each filed an Objection on January 6, 2023. On January 30, 2023 the Supreme Court issued an Order accepting and consolidating the DES and NCES appeals and denying CLF’s Motion for Summary Affirmance. On January 31, 2023, NCES filed a Motion to Stay the Supreme Court appeals pending the outcome of the Superior Court Open Meeting Law Proceeding discussed below. On February 9, 2023, CLF filed an Objection to the Motion to Stay. The Supreme Court denied the Motion to Stay on February 22, 2023. On March 2, 2023, the Supreme Court ordered the Council to prepare and file the record of the proceedings below by May 1, 2023. Once the record is filed, the Supreme Court will issue a briefing schedule. On December 14, 2022, NCES filed an action against the Council in Merrimack Superior Court (“Superior Court”) seeking to invalidate the Hearing Officer’s Order as having been adopted in violation of New Hampshire’s statute governing access to public records and meetings (“Open Meeting Law Proceeding”), in that the Council did not hold a public meeting to deliberate on the Hearing Officer’s Order prior to issuance. The Council filed a Motion to Dismiss on January 17, 2023 to which NCES filed a Summary Objection on January 18, 2023, followed by a supplemental Objection filed on February 6, 2023. Following a hearing on the merits before the Superior Court on January 18, 2023, the Superior Court ordered that NCES pursue a stay of the appeal of the Hearing Officer’s Order before the Supreme Court, and that the Superior Court would defer further ruling in the Open Meeting Law Proceeding pending a determination of whether the appeal before the Supreme Court would be stayed. On January 20, 2023, CLF filed a Motion to Intervene in the Open Meeting Law Proceeding. NCES filed an Objection on February 8, 2023, and CLF filed a Reply in Support of Motion to Intervene on February 17, 2023. The Council filed a Supplemental Memorandum of Law on February 17, 2023, to which NCES filed a Response on February 24, 2023. On April 5, 2023, the Superior Court issued an Order granting the Council’s Motion to Dismiss, which was appealed by NCES to the Supreme Court on April 18, 2023. On September 20, 2022, NCES and our subsidiary, Granite State Landfill, LLC, filed a Petition for Declaratory Judgment ("Petition") in the Superior Court seeking a determination of the meaning and constitutionality of New Hampshire’s public benefit requirement. The Petition asks the court to construe the same statute on which the Hearing Officer relied in the Hearing Officer’s Order. On September 21, 2022, NCES filed a Motion to Stay the Council proceedings pending resolution of the Petition action. DES assented to the relief sought by that motion, and CLF filed an Objection to the Motion to Stay on September 26, 2022. On October 3, 2022, NCES filed a Motion for Leave to File Reply together with its Reply to CLF’s Objection to Motion to Stay. The Hearing Officer denied the Motion to Stay by Order dated November 3, 2022. On December 19, 2022, CLF moved to intervene in the Petition proceeding before the Superior Court, and NCES filed an Objection on January 4, 2023. CLF filed a Reply on January 17, 2023, and NCES filed a Surreply on January 27, 2023. CLF’s intervention motion remains pending before the Superior Court. NCES will continue to vigorously defend the Permit through the appeals to the Supreme Court and litigation of the Petition. Environmental Remediation Liabilities 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. We accrue for costs associated with environmental remediation obligations when such costs become both probable and reasonably estimable. Determining the method and ultimate cost of remediation requires that a number of assumptions be made. There can sometimes be a range of reasonable estimates of the costs associated with remediation of a site. In these cases, we use the amount within the range that constitutes our best estimate. In the early stages of the remediation process, particular components of the overall liability may not be reasonably estimable; in this instance we use the components of the liability that can be reasonably estimated as a surrogate for the liability. It is reasonably possible that we will need to adjust the liabilities recorded for remediation to reflect the effects of new or additional information, to the extent such information impacts the costs, timing or duration of the required actions. Future changes in our estimates of the cost, timing or duration of the required actions could have a material adverse effect on our consolidated financial position, results of operations and cash flows. We disclose outstanding environmental remediation matters that remain unsettled or are settled in the reporting period that we believe could have a material adverse effect on our financial condition, results of operations or cash flows. 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. The risk-free interest rates associated with our environmental remediation liabilities as of March 31, 2023 range between 1.5% and 4.1%. A summary of the changes to the aggregate environmental remediation liabilities for the three months ended March 31, 2023 and 2022 follows: Three Months Ended 2023 2022 Beginning balance $ 6,335 $ 5,887 Accretion expense 26 26 Obligations settled (1) (18) (49) Ending balance 6,343 5,864 Less: current portion 1,131 304 Long-term portion $ 5,212 $ 5,560 (1) May include amounts paid and amounts that are being processed through accounts payable as a part of our disbursement cycle.

STOCKHOLDERS' EQUITY

STOCKHOLDERS' EQUITY	3 Months Ended
	Mar. 31, 2023
Equity [Abstract]
STOCKHOLDERS' EQUITY	STOCKHOLDERS' EQUITY Stock Based Compensation Shares Available For Issuance In the fiscal year ended December 31, 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 Stock Incentive Plan (“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, terminate or are otherwise surrendered, canceled, forfeited or repurchased by us. As of March 31, 2023, there were 649 Class A common stock equivalents available for future grant under the 2016 Plan. Stock Options 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 five-year period from the date of grant. The fair value of each stock option granted 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. A summary of stock option activity follows: Stock Options Weighted Average Exercise Price Weighted Average Remaining Contractual Term (years) Aggregate Intrinsic Value Outstanding, December 31, 2022 129 $ 55.60 Granted — $ — Exercised — $ — Forfeited — $ — Outstanding, March 31, 2023 129 $ 55.60 6.9 $ 3,504 Exercisable, March 31, 2023 49 $ 12.88 3.0 $ 3,412 Stock-based compensation expense related to stock options was $123 during the three months ended March 31, 2023, as compared to $16 during the three months ended March 31, 2022. As of March 31, 2023, we had $1,975 of unrecognized stock-based compensation expense related to outstanding stock options to be recognized over a weighted average period of 4.2 years. During the three months ended March 31, 2023, the aggregate intrinsic value of stock options exercised was zero dollars. Other Stock Awards Restricted stock awards, restricted stock units and performance stock units, with the exception of market-based 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, if applicable, the value of dividends of our Class A common stock as compared to the Russell 2000 Index over the requisite service period. Generally, restricted stock awards 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 granted to employees vest incrementally over an identified service period, typically three years, beginning on the grant date based on continued employment. Performance stock units granted to employees, including 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, as applicable. A summary of restricted stock award, restricted stock unit and performance stock unit activity follows: Restricted Stock Awards, Restricted Stock Units, and Performance Stock Units (1) Weighted Weighted Average Remaining Contractual Term (years) Aggregate Intrinsic Value Outstanding, December 31, 2022 169 $ 75.52 Granted 89 $ 79.46 Class A Common Stock Vested (50) $ 59.68 Forfeited (2) $ 70.28 Outstanding, March 31, 2023 206 $ 81.16 2.2 $ 16,988 Unvested, March 31, 2023 365 $ 82.68 2.0 $ 30,201 (1) Market-based performance stock unit grants are included at the 100% attainment level. Attainment of the maximum performance targets and market achievements would result in the issuance of an additional 159 shares of Class A common stock currently included in unvested. Stock-based compensation expense related to restricted stock awards, restricted stock units and performance stock units was $1,762 during the three months ended March 31, 2023, as compared to $2,151 during the three months ended March 31, 2022. During the three months ended March 31, 2023, the total fair value of other stock awards vested was $3,962. As of March 31, 2023, total unrecognized stock-based compensation expense related to outstanding restricted stock awards was $26, which will be recognized over a weighted average period of 1.0 year. As of March 31, 2023, total unrecognized stock-based compensation expense related to outstanding restricted stock units was $6,008, which will be recognized over a weighted average period of 2.3 years. As of March 31, 2023, total expected unrecognized stock-based compensation expense related to outstanding performance stock units was $7,990 to be recognized over a weighted average period of 2.1 years. The weighted average fair value of market-based performance stock units granted during the three months ended March 31, 2023 was $83.16 per award, which was calculated using a Monte Carlo pricing model assuming a risk-free interest rate of 4.31% and an expected volatility of 34.9% 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 $90 of stock-based compensation expense related to our Amended and Restated 1997 Employee Stock Purchase Plan during the three months ended March 31, 2023, as compared to $73 during the three months ended March 31, 2022. Accumulated Other Comprehensive Income, Net of Tax A summary of the changes in the balances of each component of accumulated other comprehensive income, net of tax follows: Interest Rate Swaps Balance, December 31, 2022 $ 7,542 Other comprehensive income before reclassifications (1,336) Amounts reclassified from accumulated other comprehensive income (1,106) Income tax benefit related to items of other comprehensive loss 673 Net current-period other comprehensive loss, net of tax (1,769) Balance, March 31, 2023 $ 5,773 A summary of reclassifications out of accumulated other comprehensive income, net of tax into earnings follows: Three Months Ended 2023 2022 Details About Accumulated Other Comprehensive Income, Net of Tax Components Amounts Reclassified Out of Accumulated Other Comprehensive Income, Net of Tax Affected Line Item in the Consolidated Interest rate swaps $ (1,106) $ 1,128 Interest expense 1,106 (1,128) Income before income taxes 303 (190) Provision for income taxes $ 803 $ (938) Net income

EARNINGS PER SHARE

EARNINGS PER SHARE	3 Months Ended
	Mar. 31, 2023
Earnings Per Share [Abstract]
EARNINGS PER SHARE	EARNINGS PER SHAREBasic earnings per share is computed by dividing net income 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, which include the assumed exercise of employee stock options, 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. A summary of the numerator and denominators used in the computation of earnings per share follows: Three Months Ended 2023 2022 Numerator: Net income $ 3,548 $ 4,190 Denominators: Number of shares outstanding, end of period: Class A common stock 50,898 50,650 Class B common stock 988 988 Unvested restricted stock (1) (2) Effect of weighted average shares outstanding (115) (146) Basic weighted average common shares outstanding 51,770 51,490 Impact of potentially dilutive securities: Dilutive effect of stock options and other stock awards 99 167 Diluted weighted average common shares outstanding 51,869 51,657 Anti-dilutive potentially issuable shares 126 78

OTHER ITEMS AND CHARGES

OTHER ITEMS AND CHARGES	3 Months Ended
	Mar. 31, 2023
Unusual or Infrequent Items, or Both [Abstract]
OTHER ITEMS AND CHARGES	OTHER ITEMS AND CHARGES Expense from Acquisition Activities In the three months ended March 31, 2023, and 2022, we recorded charges of $2,863 and $2,043, respectively, comprised primarily of legal, consulting and other similar costs associated with due diligence and the acquisition and integration of acquired businesses or select development projects.

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	3 Months Ended
	Mar. 31, 2023
Fair Value Disclosures [Abstract]
FAIR VALUE OF FINANCIAL INSTRUMENTS	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 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, contingent consideration related to acquisitions, trade payables and 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 the interest rate derivatives included in the Level 2 tier below is calculated using discounted cash flow valuation methodologies based upon one-month LIBOR or Term SOFR, as applicable, yield curves that are observable at commonly quoted intervals for the full term of the swaps. The fair value of contingent consideration - acquisition included in the Level 3 tier below is calculated using a discounted cash flow valuation methodology based upon a probability-weighted analysis of a success payment related to the potential attainment of a transfer station permit expansion. We recognize all derivatives accounted for on the balance sheet at fair value. Recurring Fair Value Measurements Summaries of our financial assets and liabilities that are measured at fair value on a recurring basis follow: Fair Value Measurement at March 31, 2023 Using: Quoted Prices in Significant Other Significant Assets: Restricted investment securities - landfill closure $ 1,972 $ — $ — Interest rate swaps — 10,100 — $ 1,972 $ 10,100 $ — Liabilities: Contingent consideration - acquisition $ — $ — $ 376 Interest rate swaps — 736 — $ — $ 736 $ 376 Fair Value Measurement at December 31, 2022 Using: Quoted Prices in Significant Other Significant Assets: Restricted investment securities - landfill closure $ 1,900 $ — $ — Interest rate swaps — 11,806 — $ 1,900 $ 11,806 $ — Liabilities: Contingent consideration - acquisition $ — $ — $ 965 Fair Value of Debt As of March 31, 2023, the fair value of our fixed rate debt, including our FAME Bonds 2005R-3, FAME Bonds 2015R-1, FAME Bonds 2015R-2, Vermont Bonds 2013, Vermont Bonds 2022A-1, New York Bonds 2014R-1, New York Bonds 2014R-2, New York Bonds 2020 and New Hampshire Bonds (collectively, the "Industrial Revenue Bonds") was approximately $186,760 and the carrying value was $197,000. The fair value of the Industrial Revenue 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 March 31, 2023, the carrying value of our Term Loan Facility was $350,000 and the carrying value of our Revolving Credit Facility was zero dollars. Their fair values are based on current borrowing rates for similar types of borrowing arrangements, or Level 2 inputs, and approximate their carrying values.

SEGMENT REPORTING

SEGMENT REPORTING	3 Months Ended
	Mar. 31, 2023
Segment Reporting [Abstract]
SEGMENT REPORTING	SEGMENT REPORTING We report selected information about our reportable 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 Eastern and Western regions. Revenues associated with our solid waste operations are derived mainly from solid waste collection and disposal services, including landfill, transfer station and transportation services, landfill gas-to-energy services, and processing services in the northeastern United States. Our Resource Solutions operating segment leverages our core competencies in materials processing, industrial recycling, organics and resource management service offerings to deliver a comprehensive solution for our larger commercial, municipal, institutional and industrial customers that have more diverse waste and recycling needs. Revenues associated with our Resource Solutions operations are comprised of processing services and services provided by our National Accounts business. Revenues from processing services are derived from customers in the form of processing fees, tipping fees, commodity sales, and organic material sales. Revenues from our National Accounts business are derived from brokerage services and overall resource management services providing a wide range of environmental services and resource management solutions to large and complex organizations, as well as traditional collection, disposal and recycling services provided to large account multi-site customers. Legal, tax, information technology, human resources, certain finance and accounting and other administrative functions are included in our Corporate Entities segment, which is not a reportable operating segment. Corporate Entities results reflect those costs not allocated to our reportable operating segments. Three Months Ended March 31, 2023 Segment Outside Inter-company Depreciation and Operating Total Eastern $ 83,909 $ 19,369 $ 11,903 $ 2,139 $ 364,872 Western 111,034 36,559 17,665 12,426 744,084 Resource Solutions 67,652 3,487 3,076 (1,943) 195,028 Corporate Entities — — 791 (2,357) 115,906 Eliminations — (59,415) — — — $ 262,595 $ — $ 33,435 $ 10,265 $ 1,419,890 Three Months Ended March 31, 2022 Segment Outside Inter-company Depreciation and Operating Total Eastern $ 71,319 $ 16,668 $ 11,450 $ (2,229) $ 355,371 Western 95,839 32,493 14,659 9,263 684,969 Resource Solutions 66,869 778 2,762 3,691 176,128 Corporate Entities — — 557 (557) 90,503 Eliminations — (49,939) — — — $ 234,027 $ — $ 29,428 $ 10,168 $ 1,306,971 A summary of our revenues attributable to services provided follows: Three Months Ended 2023 2022 Collection $ 139,977 $ 119,531 Disposal 51,466 43,153 Power generation 1,924 2,654 Processing 1,576 1,820 Solid waste operations 194,943 167,158 Processing 22,806 27,395 National Accounts 44,846 39,474 Resource Solutions operations 67,652 66,869 Total revenues $ 262,595 $ 234,027

ACCOUNTING CHANGES (Policies)

ACCOUNTING CHANGES (Policies)	3 Months Ended
	Mar. 31, 2023
Accounting Changes and Error Corrections [Abstract]
Basis of Accounting	Casella Waste Systems, Inc. (“Parent”), a Delaware corporation, and its consolidated subsidiaries (collectively, “we”, “us” or “our”), is a regional, vertically integrated solid waste services company. We provide resource management expertise and services to residential, commercial, municipal, institutional and industrial customers, primarily in the areas of solid waste collection and disposal, transfer, recycling and organics services. We provide integrated solid waste services in seven states: Vermont, New Hampshire, New York, Massachusetts, Connecticut, Maine and Pennsylvania, with our headquarters located in Rutland, Vermont. We manage our solid waste operations on a geographic basis through two regional operating segments, the Eastern and Western regions, each of which provides a full range of solid waste services. We manage our resource-renewal operations through the Resource Solutions operating segment, which leverages our core competencies in materials processing, industrial recycling, organics and resource management service offerings to deliver a comprehensive solution for our larger commercial, municipal, institutional and industrial customers that have more diverse waste and recycling needs. Legal, tax, information technology, human resources, certain finance and accounting and other administrative functions are included in our Corporate Entities segment. The accompanying unaudited consolidated financial statements, which include the accounts of the Parent and our wholly-owned subsidiaries, 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. Our significant accounting policies are more fully discussed in Item 8. " Financial Statements and Supplementary Data " of our Annual Report on Form 10-K for the fiscal year ended December 31, 2022 ("fiscal year 2022"), which was filed with the SEC on February 17, 2023 ("2022 Form 10-K").
Use of Estimates	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 the opinion of management, these consolidated financial statements include all adjustments, which include normal recurring and nonrecurring adjustments, necessary for a fair presentation of the financial position, results of operations and cash flows for the periods presented. The results for the three months ended March 31, 2023 may not be indicative of the results for any other interim period or the entire fiscal year.
Subsequent Events	We have evaluated subsequent events or transactions that have occurred after the consolidated balance sheet date of March 31, 2023 through the date of filing of the consolidated financial statements with the SEC on this Quarterly Report on Form 10-Q. Except as disclosed, no material subsequent events have occurred since March 31, 2023 through the date of this filing that would require recognition or disclosure in our consolidated financial statements.
Accounting Standards Adopted and Pending Adoption	table provides a brief description of a recent Accounting Standards Update ("ASU(s)") to the Accounting Standards Codification ("ASC") issued by the Financial Accounting Standards Board (“FASB”) that we adopted and is deemed to have a possible material impact on our consolidated financial statements based on current account balances and activity: Standard Description Effect on the Financial Statements or Other Accounting standards adopted effective January 1, 2023 ASU No. 2020-04: Reference Rate Reform (Topic 848), as amended through December 2022 Provides temporary optional guidance to ease the potential burden in applying GAAP to contract modifications and hedging relationships that reference London Inter-Bank Offered Rate ("LIBOR") or another reference rate expected to be discontinued, subject to meeting certain criteria. We currently have interest rate derivative agreements with hedging relationships that reference LIBOR, which is going to be discontinued effective July 1, 2023. This guidance provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions affected by reference rate reform if certain criteria are met. Effective the three months ended March 31, 2023, we elected optional expedients under this guidance that provide temporary relief over contract modifications and hedge accounting in order to maintain hedge effectiveness upon modifying contract terms related to reference rate reform in our amended and restated credit agreement, dated as of December 22, 2021, as amended by the first amendment, dated as of February 9, 2023, and the second amendment, dated as of February 9, 2023 (the "Amended and Restated Credit Agreement") and to transition our interest rate derivative agreements from LIBOR to another reference rate prior to the planned discontinuation of LIBOR on July 1, 2023. See Note 7, Debt. This guidance will be in effect through December 31, 2024.
Accrued Final Capping, Closure and Post Closure	Accrued 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. 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.
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 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, contingent consideration related to acquisitions, trade payables and 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 the interest rate derivatives included in the Level 2 tier below is calculated using discounted cash flow valuation methodologies based upon one-month LIBOR or Term SOFR, as applicable, yield curves that are observable at commonly quoted intervals for the full term of the swaps. The fair value of contingent consideration - acquisition included in the Level 3 tier below is calculated using a discounted cash flow valuation methodology based upon a probability-weighted analysis of a success payment related to the potential attainment of a transfer station permit expansion. We recognize all derivatives accounted for on the balance sheet at fair value.
Segment Reporting	We report selected information about our reportable 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 Eastern and Western regions. Revenues associated with our solid waste operations are derived mainly from solid waste collection and disposal services, including landfill, transfer station and transportation services, landfill gas-to-energy services, and processing services in the northeastern United States. Our Resource Solutions operating segment leverages our core competencies in materials processing, industrial recycling, organics and resource management service offerings to deliver a comprehensive solution for our larger commercial, municipal, institutional and industrial customers that have more diverse waste and recycling needs. Revenues associated with our Resource Solutions operations are comprised of processing services and services provided by our National Accounts business. Revenues from processing services are derived from customers in the form of processing fees, tipping fees, commodity sales, and organic material sales. Revenues from our National Accounts business are derived from brokerage services and overall resource management services providing a wide range of environmental services and resource management solutions to large and complex organizations, as well as traditional collection, disposal and recycling services provided to large account multi-site customers. Legal, tax, information technology, human resources, certain finance and accounting and other administrative functions are included in our Corporate Entities segment, which is not a reportable operating segment. Corporate Entities results reflect those costs not allocated to our reportable operating segments.

ACCOUNTING CHANGES (Tables)

ACCOUNTING CHANGES (Tables)	3 Months Ended
	Mar. 31, 2023
Accounting Changes and Error Corrections [Abstract]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	The following table provides a brief description of a recent Accounting Standards Update ("ASU(s)") to the Accounting Standards Codification ("ASC") issued by the Financial Accounting Standards Board (“FASB”) that we adopted and is deemed to have a possible material impact on our consolidated financial statements based on current account balances and activity: Standard Description Effect on the Financial Statements or Other Accounting standards adopted effective January 1, 2023 ASU No. 2020-04: Reference Rate Reform (Topic 848), as amended through December 2022 Provides temporary optional guidance to ease the potential burden in applying GAAP to contract modifications and hedging relationships that reference London Inter-Bank Offered Rate ("LIBOR") or another reference rate expected to be discontinued, subject to meeting certain criteria. We currently have interest rate derivative agreements with hedging relationships that reference LIBOR, which is going to be discontinued effective July 1, 2023. This guidance provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions affected by reference rate reform if certain criteria are met. Effective the three months ended March 31, 2023, we elected optional expedients under this guidance that provide temporary relief over contract modifications and hedge accounting in order to maintain hedge effectiveness upon modifying contract terms related to reference rate reform in our amended and restated credit agreement, dated as of December 22, 2021, as amended by the first amendment, dated as of February 9, 2023, and the second amendment, dated as of February 9, 2023 (the "Amended and Restated Credit Agreement") and to transition our interest rate derivative agreements from LIBOR to another reference rate prior to the planned discontinuation of LIBOR on July 1, 2023. See Note 7, Debt. This guidance will be in effect through December 31, 2024.

REVENUE RECOGNITION (Tables)

REVENUE RECOGNITION (Tables)	3 Months Ended
	Mar. 31, 2023
Revenue from Contract with Customer [Abstract]
Schedule of Disaggregation of Revenue	The following tables set forth revenues disaggregated by service line and timing of revenue recognition by operating segment for each of the three months ended March 31, 2023 and 2022: Three Months Ended March 31, 2023 Eastern Western Resource Solutions Total Revenues Collection $ 61,108 $ 78,869 $ — $ 139,977 Landfill 6,301 16,460 — 22,761 Transfer station 13,981 9,961 — 23,942 Transportation 1,183 3,580 — 4,763 Landfill gas-to-energy 213 1,711 — 1,924 Processing 1,123 453 22,806 24,382 National Accounts — — 44,846 44,846 Total revenues $ 83,909 $ 111,034 $ 67,652 $ 262,595 Transferred at a point-in-time $ 119 $ 731 $ 6,438 $ 7,288 Transferred over time 83,790 110,303 61,214 255,307 Total revenues $ 83,909 $ 111,034 $ 67,652 $ 262,595 Three Months Ended March 31, 2022 Eastern Western Resource Solutions Total Revenues Collection $ 51,497 $ 68,034 $ — $ 119,531 Landfill 5,376 14,190 — 19,566 Transfer station 11,613 7,844 — 19,457 Transportation 1,472 2,658 — 4,130 Landfill gas-to-energy 274 2,380 — 2,654 Processing 1,087 733 27,395 29,215 National Accounts — — 39,474 39,474 Total revenues $ 71,319 $ 95,839 $ 66,869 $ 234,027 Transferred at a point-in-time $ 120 $ 511 $ 15,086 $ 15,717 Transferred over time 71,199 95,328 51,783 218,310 Total revenues $ 71,319 $ 95,839 $ 66,869 $ 234,027

INTANGIBLE ASSETS (Tables)

INTANGIBLE ASSETS (Tables)	3 Months Ended
	Mar. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of Intangible Assets by Type	Summaries of intangible assets by type follows: Covenants Customer Relationships Trade Names Total Balance, March 31, 2023 Intangible assets $ 31,201 $ 127,179 $ 8,405 $ 166,785 Less accumulated amortization (24,593) (49,172) (5,308) (79,073) $ 6,608 $ 78,007 $ 3,097 $ 87,712 Covenants Customer Relationships Trade Names Total Balance, December 31, 2022 Intangible assets $ 31,201 $ 127,179 $ 8,405 $ 166,785 Less accumulated amortization (24,129) (46,162) (4,711) (75,002) $ 7,072 $ 81,017 $ 3,694 $ 91,783
Summary of Intangible Amortization Expense Estimated	A summary of intangible amortization expense estimated for each of the next five fiscal years following fiscal year 2022 and thereafter is estimated as follows: Estimated Future Amortization Expense as of March 31, 2023 Fiscal year ending December 31, 2023 $ 12,071 Fiscal year ending December 31, 2024 $ 15,471 Fiscal year ending December 31, 2025 $ 14,429 Fiscal year ending December 31, 2026 $ 12,745 Fiscal year ending December 31, 2027 $ 11,266 Thereafter $ 21,730

OTHER ACCRUED LIABILITIES (Tabl

OTHER ACCRUED LIABILITIES (Tables)	3 Months Ended
	Mar. 31, 2023
Payables and Accruals [Abstract]
Schedule of Accrued Liabilities	A summary of other accrued liabilities, classified as current liabilities follows: March 31, December 31, Self insurance reserve - current portion $ 7,691 $ 7,422 Accrued capital expenditures 4,000 10,842 Other accrued liabilities 23,264 27,973 Total $ 34,955 $ 46,237

ACCRUED FINAL CAPPING, CLOSUR_2

ACCRUED FINAL CAPPING, CLOSURE AND POST CLOSURE (Tables)	3 Months Ended
	Mar. 31, 2023
Asset Retirement Obligation Disclosure [Abstract]
Summary of Changes to Accrued Capping, Closure and Post-Closure Liabilities	A summary of the changes to accrued final capping, closure and post-closure liabilities follows: Three Months Ended 2023 2022 Beginning balance $ 113,678 $ 86,914 Obligations incurred 1,247 966 Accretion expense 2,410 1,873 Obligations settled (1) (1,179) (926) Ending balance $ 116,156 $ 88,827 (1) May include amounts that are being processed through accounts payable as a part of our disbursements cycle.

DEBT (Tables)

DEBT (Tables)	3 Months Ended
	Mar. 31, 2023
Debt And Derivatives Disclosure [Abstract]
Summary of Debt	A summary of debt is as follows: March 31, December 31, Senior Secured Credit Facility: Term loan A facility ("Term Loan Facility") due December 2026; bearing interest at term secured overnight financing rate ("Term SOFR") plus 1.135% $ 350,000 $ 350,000 Revolving credit facility ("Revolving Credit Facility") due December 2026; bearing interest at Term SOFR plus 1.135% — 6,000 Tax-Exempt Bonds: New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014 ("New York Bonds 2014R-1") 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 New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2020 ("New York Bonds 2020") due September 2050 - fixed rate interest period through 2025; bearing interest at 2.750% 40,000 40,000 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 2013") due April 2036 - fixed rate interest period through 2028; bearing interest at 4.625% 16,000 16,000 Vermont Economic Development Authority Solid Waste Disposal Long-Term Revenue Bonds Series 2022A-1 ("Vermont Bonds 2022A-1") due June 2052 - fixed rate interest period through 2027; bearing interest at 5.00% 35,000 35,000 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 48,800 49,813 Notes payable maturing through August 2024; bearing interest up to 4.0% 316 664 Principal amount of debt 596,116 603,477 Less—unamortized debt issuance costs (1) 9,275 9,494 Debt less unamortized debt issuance costs 586,841 593,983 Less—current maturities of debt 9,274 8,968 $ 577,567 $ 585,015 (1) A summary of unamortized debt issuance costs by debt instrument follows: March 31, December 31, Revolving Credit Facility and Term Loan Facility (collectively, the "Credit Facility") $ 4,692 $ 4,716 New York Bonds 2014R-1 849 866 New York Bonds 2014R-2 192 207 New York Bonds 2020 1,061 1,106 FAME Bonds 2005R-3 155 176 FAME Bonds 2015R-1 326 344 FAME Bonds 2015R-2 175 193 Vermont Bonds 2013 365 378 Vermont Bonds 2022A-1 1,111 1,144 New Hampshire Bonds 349 364 $ 9,275 $ 9,494
Summary of Cash Flow Hedges	A summary of the effect of cash flow hedges related to derivative instruments on the consolidated balance sheet follows: Fair Value Balance Sheet Location March 31, December 31, Interest rate swaps Other current assets $ 4,388 $ 4,345 Interest rate swaps Other non-current assets 5,712 7,461 $ 10,100 $ 11,806 Interest rate swaps Other long-term liabilities $ 736 $ — Interest rate swaps Accumulated other comprehensive income, net of tax $ 9,364 $ 11,806 Interest rate swaps - tax effect Accumulated other comprehensive income, net of tax (3,591) (4,264) $ 5,773 $ 7,542

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	3 Months Ended
	Mar. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Summary of Environmental Liability	A summary of the changes to the aggregate environmental remediation liabilities for the three months ended March 31, 2023 and 2022 follows: Three Months Ended 2023 2022 Beginning balance $ 6,335 $ 5,887 Accretion expense 26 26 Obligations settled (1) (18) (49) Ending balance 6,343 5,864 Less: current portion 1,131 304 Long-term portion $ 5,212 $ 5,560 (1) May include amounts paid and amounts that are being processed through accounts payable as a part of our disbursement cycle.

STOCKHOLDERS' EQUITY (Tables)

STOCKHOLDERS' EQUITY (Tables)	3 Months Ended
	Mar. 31, 2023
Equity [Abstract]
Summary of Stock Option Activity	A summary of stock option activity follows: Stock Options Weighted Average Exercise Price Weighted Average Remaining Contractual Term (years) Aggregate Intrinsic Value Outstanding, December 31, 2022 129 $ 55.60 Granted — $ — Exercised — $ — Forfeited — $ — Outstanding, March 31, 2023 129 $ 55.60 6.9 $ 3,504 Exercisable, March 31, 2023 49 $ 12.88 3.0 $ 3,412
Summary of Restricted Stock, Restricted Stock Unit and Performance Stock Unit Activity	A summary of restricted stock award, restricted stock unit and performance stock unit activity follows: Restricted Stock Awards, Restricted Stock Units, and Performance Stock Units (1) Weighted Weighted Average Remaining Contractual Term (years) Aggregate Intrinsic Value Outstanding, December 31, 2022 169 $ 75.52 Granted 89 $ 79.46 Class A Common Stock Vested (50) $ 59.68 Forfeited (2) $ 70.28 Outstanding, March 31, 2023 206 $ 81.16 2.2 $ 16,988 Unvested, March 31, 2023 365 $ 82.68 2.0 $ 30,201 (1) Market-based performance stock unit grants are included at the 100% attainment level. Attainment of the maximum performance targets and market achievements would result in the issuance of an additional 159 shares of Class A common stock currently included in unvested.
Summary of Changes in Balances of Each Component of Accumulated Other Comprehensive Loss	A summary of the changes in the balances of each component of accumulated other comprehensive income, net of tax follows: Interest Rate Swaps Balance, December 31, 2022 $ 7,542 Other comprehensive income before reclassifications (1,336) Amounts reclassified from accumulated other comprehensive income (1,106) Income tax benefit related to items of other comprehensive loss 673 Net current-period other comprehensive loss, net of tax (1,769) Balance, March 31, 2023 $ 5,773
Summary of Reclassifications Out of Accumulated Other Comprehensive Loss	A summary of reclassifications out of accumulated other comprehensive income, net of tax into earnings follows: Three Months Ended 2023 2022 Details About Accumulated Other Comprehensive Income, Net of Tax Components Amounts Reclassified Out of Accumulated Other Comprehensive Income, Net of Tax Affected Line Item in the Consolidated Interest rate swaps $ (1,106) $ 1,128 Interest expense 1,106 (1,128) Income before income taxes 303 (190) Provision for income taxes $ 803 $ (938) Net income

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	3 Months Ended
	Mar. 31, 2023
Earnings Per Share [Abstract]
Summary of Earnings per Share Computation	A summary of the numerator and denominators used in the computation of earnings per share follows: Three Months Ended 2023 2022 Numerator: Net income $ 3,548 $ 4,190 Denominators: Number of shares outstanding, end of period: Class A common stock 50,898 50,650 Class B common stock 988 988 Unvested restricted stock (1) (2) Effect of weighted average shares outstanding (115) (146) Basic weighted average common shares outstanding 51,770 51,490 Impact of potentially dilutive securities: Dilutive effect of stock options and other stock awards 99 167 Diluted weighted average common shares outstanding 51,869 51,657 Anti-dilutive potentially issuable shares 126 78

FAIR VALUE OF FINANCIAL INSTR_2

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	3 Months Ended
	Mar. 31, 2023
Fair Value Disclosures [Abstract]
Summary of Financial Assets and Liabilities Measured at Fair Value	Summaries of our financial assets and liabilities that are measured at fair value on a recurring basis follow: Fair Value Measurement at March 31, 2023 Using: Quoted Prices in Significant Other Significant Assets: Restricted investment securities - landfill closure $ 1,972 $ — $ — Interest rate swaps — 10,100 — $ 1,972 $ 10,100 $ — Liabilities: Contingent consideration - acquisition $ — $ — $ 376 Interest rate swaps — 736 — $ — $ 736 $ 376 Fair Value Measurement at December 31, 2022 Using: Quoted Prices in Significant Other Significant Assets: Restricted investment securities - landfill closure $ 1,900 $ — $ — Interest rate swaps — 11,806 — $ 1,900 $ 11,806 $ — Liabilities: Contingent consideration - acquisition $ — $ — $ 965

SEGMENT REPORTING (Tables)

SEGMENT REPORTING (Tables)	3 Months Ended
	Mar. 31, 2023
Segment Reporting [Abstract]
Summary of Segment Reporting Information by Segment	Three Months Ended March 31, 2023 Segment Outside Inter-company Depreciation and Operating Total Eastern $ 83,909 $ 19,369 $ 11,903 $ 2,139 $ 364,872 Western 111,034 36,559 17,665 12,426 744,084 Resource Solutions 67,652 3,487 3,076 (1,943) 195,028 Corporate Entities — — 791 (2,357) 115,906 Eliminations — (59,415) — — — $ 262,595 $ — $ 33,435 $ 10,265 $ 1,419,890 Three Months Ended March 31, 2022 Segment Outside Inter-company Depreciation and Operating Total Eastern $ 71,319 $ 16,668 $ 11,450 $ (2,229) $ 355,371 Western 95,839 32,493 14,659 9,263 684,969 Resource Solutions 66,869 778 2,762 3,691 176,128 Corporate Entities — — 557 (557) 90,503 Eliminations — (49,939) — — — $ 234,027 $ — $ 29,428 $ 10,168 $ 1,306,971
Summary of Revenue Attributable to Services	A summary of our revenues attributable to services provided follows: Three Months Ended 2023 2022 Collection $ 139,977 $ 119,531 Disposal 51,466 43,153 Power generation 1,924 2,654 Processing 1,576 1,820 Solid waste operations 194,943 167,158 Processing 22,806 27,395 National Accounts 44,846 39,474 Resource Solutions operations 67,652 66,869 Total revenues $ 262,595 $ 234,027

BASIS OF PRESENTATION (Details)

BASIS OF PRESENTATION (Details)	3 Months Ended
	Mar. 31, 2023 regionalOperatingSegment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of regional operating segments	2

REVENUE RECOGNITION - Disaggreg

REVENUE RECOGNITION - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Disaggregation of Revenue [Line Items]
Total revenues	$ 262,595	$ 234,027
Collection
Disaggregation of Revenue [Line Items]
Total revenues	139,977	119,531
Landfill
Disaggregation of Revenue [Line Items]
Total revenues	22,761	19,566
Transfer station
Disaggregation of Revenue [Line Items]
Total revenues	23,942	19,457
Transportation
Disaggregation of Revenue [Line Items]
Total revenues	4,763	4,130
Landfill gas-to-energy
Disaggregation of Revenue [Line Items]
Total revenues	1,924	2,654
Processing
Disaggregation of Revenue [Line Items]
Total revenues	24,382	29,215
National Accounts
Disaggregation of Revenue [Line Items]
Total revenues	44,846	39,474
Transferred at a point-in-time
Disaggregation of Revenue [Line Items]
Total revenues	7,288	15,717
Transferred over time
Disaggregation of Revenue [Line Items]
Total revenues	255,307	218,310
Eastern
Disaggregation of Revenue [Line Items]
Total revenues	83,909	71,319
Eastern | Collection
Disaggregation of Revenue [Line Items]
Total revenues	61,108	51,497
Eastern | Landfill
Disaggregation of Revenue [Line Items]
Total revenues	6,301	5,376
Eastern | Transfer station
Disaggregation of Revenue [Line Items]
Total revenues	13,981	11,613
Eastern | Transportation
Disaggregation of Revenue [Line Items]
Total revenues	1,183	1,472
Eastern | Landfill gas-to-energy
Disaggregation of Revenue [Line Items]
Total revenues	213	274
Eastern | Processing
Disaggregation of Revenue [Line Items]
Total revenues	1,123	1,087
Eastern | National Accounts
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Eastern | Transferred at a point-in-time
Disaggregation of Revenue [Line Items]
Total revenues	119	120
Eastern | Transferred over time
Disaggregation of Revenue [Line Items]
Total revenues	83,790	71,199
Western
Disaggregation of Revenue [Line Items]
Total revenues	111,034	95,839
Western | Collection
Disaggregation of Revenue [Line Items]
Total revenues	78,869	68,034
Western | Landfill
Disaggregation of Revenue [Line Items]
Total revenues	16,460	14,190
Western | Transfer station
Disaggregation of Revenue [Line Items]
Total revenues	9,961	7,844
Western | Transportation
Disaggregation of Revenue [Line Items]
Total revenues	3,580	2,658
Western | Landfill gas-to-energy
Disaggregation of Revenue [Line Items]
Total revenues	1,711	2,380
Western | Processing
Disaggregation of Revenue [Line Items]
Total revenues	453	733
Western | National Accounts
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Western | Transferred at a point-in-time
Disaggregation of Revenue [Line Items]
Total revenues	731	511
Western | Transferred over time
Disaggregation of Revenue [Line Items]
Total revenues	110,303	95,328
Resource Solutions
Disaggregation of Revenue [Line Items]
Total revenues	67,652	66,869
Resource Solutions | Collection
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Resource Solutions | Landfill
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Resource Solutions | Transfer station
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Resource Solutions | Transportation
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Resource Solutions | Landfill gas-to-energy
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Resource Solutions | Processing
Disaggregation of Revenue [Line Items]
Total revenues	22,806	27,395
Resource Solutions | National Accounts
Disaggregation of Revenue [Line Items]
Total revenues	44,846	39,474
Resource Solutions | Transferred at a point-in-time
Disaggregation of Revenue [Line Items]
Total revenues	6,438	15,086
Resource Solutions | Transferred over time
Disaggregation of Revenue [Line Items]
Total revenues	$ 61,214	$ 51,783

REVENUE RECOGNITION - Narrative

REVENUE RECOGNITION - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Rebates	$ (262,595,000)	$ (234,027,000)
Revenue recognized fro performance obligation satisfied in previous period	0	0
Gross receivables from contracts	97,340,000		$ 102,234,000
Contract liabilities	4,146,000		$ 3,742,000
Rebate for Recycled or Returned Organic Materials
Disaggregation of Revenue [Line Items]
Rebates	$ 6,629,000	$ 3,794,000

INTANGIBLE ASSETS - Summary of

INTANGIBLE ASSETS - Summary of Intangible Assets by Type (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Intangible assets	$ 166,785	$ 166,785
Less accumulated amortization	(79,073)	(75,002)
Intangible assets, net	87,712	91,783
Covenants not-to-compete
Finite-Lived Intangible Assets [Line Items]
Intangible assets	31,201	31,201
Less accumulated amortization	(24,593)	(24,129)
Intangible assets, net	6,608	7,072
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Intangible assets	127,179	127,179
Less accumulated amortization	(49,172)	(46,162)
Intangible assets, net	78,007	81,017
Trade Names
Finite-Lived Intangible Assets [Line Items]
Intangible assets	8,405	8,405
Less accumulated amortization	(5,308)	(4,711)
Intangible assets, net	$ 3,097	$ 3,694

INTANGIBLE ASSETS - Narrative (

INTANGIBLE ASSETS - Narrative (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible amortization expense	$ 4,071	$ 3,789

INTANGIBLE ASSETS - Summary o_2

INTANGIBLE ASSETS - Summary of Intangible Amortization Expense Estimated (Detail) $ in Thousands	Mar. 31, 2023 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Fiscal year ending December 31, 2023	$ 12,071
Fiscal year ending December 31, 2024	15,471
Fiscal year ending December 31, 2025	14,429
Fiscal year ending December 31, 2026	12,745
Fiscal year ending December 31, 2027	11,266
Thereafter	$ 21,730

OTHER ACCRUED LIABILITIES (Deta

OTHER ACCRUED LIABILITIES (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Self insurance reserve - current portion	$ 7,691	$ 7,422
Accrued capital expenditures	4,000	10,842
Other accrued liabilities	23,264	27,973
Total	$ 34,955	$ 46,237

ACCRUED FINAL CAPPING, CLOSUR_3

ACCRUED FINAL CAPPING, CLOSURE AND POST CLOSURE - Summary of Changes to Accrued Capping, Closure and Post-Closure Liabilities (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	$ 113,678	$ 86,914
Obligations incurred	1,247	966
Accretion expense	2,410	1,873
Obligations settled	(1,179)	(926)
Ending balance	$ 116,156	$ 88,827

DEBT - Summary of Debt (Details

DEBT - Summary of Debt (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Weighted-average discount rate - finance leases	3.70%
Finance leases maturing through December 2107; bearing interest at a weighted average of 3.7%	$ 48,800	$ 49,813
Principal amount of debt	596,116	603,477
Less - unamortized debt issuance costs	9,275	9,494
Debt less unamortized debt issuance costs	586,841	593,983
Less—current maturities of debt	9,274	8,968
Debt, less current portion	$ 577,567	$ 585,015
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Debt, less current portion	Debt, less current portion
Secured Debt | Term loan A facility ("Term Loan Facility") due December 2026; bearing interest at term secured overnight financing rate ("Term SOFR") plus 1.135%
Debt Instrument [Line Items]
Principal amount of debt	$ 350,000	$ 350,000
Secured Debt | Term loan A facility ("Term Loan Facility") due December 2026; bearing interest at term secured overnight financing rate ("Term SOFR") plus 1.135% | SOFR
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	1.135%
Line of Credit | Revolving credit facility ("Revolving Credit Facility") due December 2026; bearing interest at Term SOFR plus 1.135%
Debt Instrument [Line Items]
Principal amount of debt	$ 0	6,000
Credit Facility | Revolving Credit Facility and Term Loan Facility (collectively, the "Credit Facility")
Debt Instrument [Line Items]
Less - unamortized debt issuance costs	$ 4,692	4,716
Unsecured Debt | New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014 ("New York Bonds 2014R-1") due December 2044 - fixed rate interest period through 2029; bearing interest at 2.875%
Debt Instrument [Line Items]
Stated interest rate	2.875%
Principal amount of debt	$ 25,000	25,000
Less - unamortized debt issuance costs	$ 849	866
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]
Stated interest rate	3.125%
Principal amount of debt	$ 15,000	15,000
Less - unamortized debt issuance costs	$ 192	207
Unsecured Debt | New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2020 ("New York Bonds 2020") due September 2050 - fixed rate interest period through 2025; bearing interest at 2.750%
Debt Instrument [Line Items]
Stated interest rate	2.75%
Principal amount of debt	$ 40,000	40,000
Less - unamortized debt issuance costs	$ 1,061	1,106
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]
Stated interest rate	5.25%
Principal amount of debt	$ 25,000	25,000
Less - unamortized debt issuance costs	$ 155	176
Unsecured Debt | 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]
Stated interest rate	5.125%
Principal amount of debt	$ 15,000	15,000
Less - unamortized debt issuance costs	$ 326	344
Unsecured Debt | 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]
Stated interest rate	4.375%
Principal amount of debt	$ 15,000	15,000
Less - unamortized debt issuance costs	$ 175	193
Unsecured Debt | Vermont Economic Development Authority Solid Waste Disposal Long-Term Revenue Bonds Series 2013 ("Vermont Bonds 2013") due April 2036 - fixed rate interest period through 2028; bearing interest at 4.625%
Debt Instrument [Line Items]
Stated interest rate	4.625%
Principal amount of debt	$ 16,000	16,000
Less - unamortized debt issuance costs	$ 365	378
Unsecured Debt | Vermont Economic Development Authority Solid Waste Disposal Long-Term Revenue Bonds Series 2022A-1 ("Vermont Bonds 2022A-1") due June 2052 - fixed rate interest period through 2027; bearing interest at 5.00%
Debt Instrument [Line Items]
Stated interest rate	5%
Principal amount of debt	$ 35,000	35,000
Less - unamortized debt issuance costs	$ 1,111	1,144
Unsecured Debt | 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]
Stated interest rate	2.95%
Principal amount of debt	$ 11,000	11,000
Less - unamortized debt issuance costs	$ 349	364
Notes payable maturing through August 2024; bearing interest up to 4.0%
Debt Instrument [Line Items]
Stated interest rate	4%
Principal amount of debt	$ 316	$ 664

DEBT - Financing Activities (De

DEBT - Financing Activities (Details) - Subsequent Event $ in Thousands		1 Months Ended
	Apr. 21, 2023 USD ($) hauling_operation facility transfer_station	Apr. 30, 2023 business	Apr. 28, 2023 USD ($)
Line of Credit Facility [Line Items]
Number of businesses acquired | business		4
GFL Environmental Inc
Line of Credit Facility [Line Items]
Percent of interest acquired	100%
Payment to acquire business	$ 525,000
Number of hauling operations | hauling_operation	9
Number of transfer stations | transfer_station	1
Number of material recovery facilities | facility	1
Secured Debt
Line of Credit Facility [Line Items]
Bridge loan			$ 375,000
Secured Debt | Term Loan A
Line of Credit Facility [Line Items]
Credit facility, current borrowing capacity			261,500
Credit facility, maximum borrowing capacity			$ 400,000

DEBT - Credit Facility (Details

DEBT - Credit Facility (Details) - USD ($)		3 Months Ended
	Feb. 09, 2023	Mar. 31, 2023
Line of Credit Facility [Line Items]
Additional revolver capacity		$ 125,000,000
Line of Credit
Line of Credit Facility [Line Items]
Facility term		5 years
Remaining capacity		$ 272,267,000
Line of credit drawn		0
Credit Facility
Line of Credit Facility [Line Items]
Interest rate, annual increase upon payment default	2%
Interest rate, annual increase upon other event of default	2%
Credit Facility | Minimum | Variable Rate Component Two
Line of Credit Facility [Line Items]
Basis spread on variable rate (as a percent)	0.20%
Credit Facility | Maximum | Variable Rate Component Two
Line of Credit Facility [Line Items]
Basis spread on variable rate (as a percent)	0.40%
Credit Facility | SOFR
Line of Credit Facility [Line Items]
Variable rate adjustment	0.10%
Credit Facility | SOFR | Variable Rate Component One
Line of Credit Facility [Line Items]
Variable rate adjustment	0.04%
Credit Facility | SOFR | Minimum | Variable Rate Component One
Line of Credit Facility [Line Items]
Basis spread on variable rate (as a percent)	1.125%
Credit Facility | SOFR | Maximum | Variable Rate Component One
Line of Credit Facility [Line Items]
Basis spread on variable rate (as a percent)	2.125%
Secured Debt | Term loan A facility ("Term Loan Facility") due December 2026; bearing interest at term secured overnight financing rate ("Term SOFR") plus 1.135%
Line of Credit Facility [Line Items]
Aggregate principal amount issued		$ 350,000,000
Secured Debt | Term loan A facility ("Term Loan Facility") due December 2026; bearing interest at term secured overnight financing rate ("Term SOFR") plus 1.135% | SOFR
Line of Credit Facility [Line Items]
Basis spread on variable rate (as a percent)		1.135%
Line of Credit | Credit Facility | Letter of Credit
Line of Credit Facility [Line Items]
Fronting fee	0.25%
Revolving Credit Facility | Revolving credit facility ("Revolving Credit Facility") due December 2026; bearing interest at Term SOFR plus 1.135% | Letter of Credit
Line of Credit Facility [Line Items]
Letters of credit sublimit		$ 75,000,000
Revolving Credit Facility | Revolving credit facility ("Revolving Credit Facility") due December 2026; bearing interest at Term SOFR plus 1.135% | Line of Credit
Line of Credit Facility [Line Items]
Credit facility maximum		300,000,000
Outstanding irrevocable letters of credit totaling		$ 27,733,000

DEBT - Cash Flow Hedges Narrati

DEBT - Cash Flow Hedges Narrative (Details) - Cash Flow Hedging - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Interest Rate Derivative
Debt Instrument [Line Items]
Notional amount	$ 190,000
Floor interest rate (as a percent)	0%
Weighted average percentage rate paid (as a percent)	2.20%
Forward Starting Interest Rate Derivative
Debt Instrument [Line Items]
Notional amount	$ 60,000	$ 20,000
Weighted average percentage rate paid (as a percent)	2.80%
Forward Interest Rate Contract, LIBOR Interest
Debt Instrument [Line Items]
Notional amount	$ 20,000
Floor interest rate (as a percent)	0%
Forward Interest Rate Contract, SOFR Interest
Debt Instrument [Line Items]
Notional amount	$ 40,000
Floor interest rate (as a percent)	0%

DEBT - Summary of Cash Flow Hed

DEBT - Summary of Cash Flow Hedges (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Derivatives, Fair Value [Line Items]
Accumulated other comprehensive income, net of tax	$ 5,773	$ 7,542
Designated as Hedging Instrument | Interest rate swaps
Derivatives, Fair Value [Line Items]
Cash flow hedge derivatives, gross asset	10,100	11,806
Designated as Hedging Instrument | Interest rate swaps | Accumulated gain (loss), cash flow hedge
Derivatives, Fair Value [Line Items]
Accumulated other comprehensive income, before tax	9,364	11,806
Accumulated other comprehensive income, tax	(3,591)	(4,264)
Accumulated other comprehensive income, net of tax	5,773	7,542
Other current assets | Designated as Hedging Instrument | Interest rate swaps
Derivatives, Fair Value [Line Items]
Cash flow hedge derivatives, gross asset	4,388	4,345
Other non-current assets | Designated as Hedging Instrument | Interest rate swaps
Derivatives, Fair Value [Line Items]
Cash flow hedge derivatives, gross asset	5,712	7,461
Other long-term liabilities | Designated as Hedging Instrument | Interest rate swaps
Derivatives, Fair Value [Line Items]
Cash flow hedge derivatives, gross liability	$ 736	$ 0

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Narrative (Detail) $ in Thousands	Mar. 31, 2023 USD ($)
Loss Contingencies [Line Items]
Loss contingency accrual	$ 821
Minimum
Loss Contingencies [Line Items]
Risk free interest (as a percent)	1.50%
Maximum
Loss Contingencies [Line Items]
Risk free interest (as a percent)	4.10%

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES - Environmental Remediation Liability (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	$ 6,335	$ 5,887
Obligations settled	(18)	(49)
Ending balance	6,343	5,864
Less: current portion	1,131	304
Long-term portion	5,212	5,560
Other environmental remediation sites
Accrual for Environmental Loss Contingencies [Roll Forward]
Accretion expense	$ 26	$ 26

STOCKHOLDERS' EQUITY - Narrativ

STOCKHOLDERS' EQUITY - Narrative (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation, weighted average period	4 years 2 months 12 days
Fair value of stock awards vested	$ 3,962,000
Stock Options
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense	123,000	$ 16,000
Unrecognized stock-based compensation expense, stock options	1,975,000
Aggregate intrinsic value of options exercised	0
Restricted Stock Awards, Restricted Stock Units And Performance Stock Units
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense	1,762,000	2,151,000
Restricted Stock
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense	$ 26,000
Restricted Stock | Non Employee Director
Limited Partners' Capital Account [Line Items]
Award vesting period	3 years
Restricted Stock Unit
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense	$ 6,008,000
Restricted Stock Unit | Non Employee Director
Limited Partners' Capital Account [Line Items]
Award service period	3 years
Performance Stock Unit
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense	$ 7,990,000
Market-based Performance Stock Units
Limited Partners' Capital Account [Line Items]
Weighted average fair value of market-based performance (in dollars per share)	$ 83.16
Risk-free interest rate	4.31%
Expected volatility	34.90%
Weighted average | Restricted Stock
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation, weighted average period	1 year
Weighted average | Restricted Stock Unit
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation, weighted average period	2 years 3 months 18 days
Weighted average | Performance Stock Unit
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation, weighted average period	2 years 1 month 6 days
2016 Plan
Limited Partners' Capital Account [Line Items]
Expiration period	10 years
2016 Plan | Minimum
Limited Partners' Capital Account [Line Items]
Award vesting period	1 year
2016 Plan | Maximum
Limited Partners' Capital Account [Line Items]
Award vesting period	5 years
Amended and Restated 1997 Employee Stock Purchase Plan
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense	$ 90,000	$ 73,000
Class A Common Stock | 2016 Plan
Limited Partners' Capital Account [Line Items]
Common stock, authorized shares (in shares)	2,250,000
Number of shares available for future grant (in shares)	649,000
Class A Common Stock | 2006 Incentive Plan
Limited Partners' Capital Account [Line Items]
Common stock, additional authorized shares (in shares)	2,723,000

STOCKHOLDERS' EQUITY - Summary

STOCKHOLDERS' EQUITY - Summary of Stock Option Activity (Detail) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($) $ / shares shares
Stock Options
Beginning balance, outstanding (in shares) | shares	129
Granted (in shares) | shares	0
Exercised (in shares) | shares	0
Forfeited (in shares) | shares	0
Ending balance, outstanding (in shares) | shares	129
Exercisable at end of period (in shares) | shares	49
Weighted Average Exercise Price
Beginning balance, outstanding (in dollars per share) | $ / shares	$ 55.60
Granted (in dollars per share) | $ / shares	0
Exercised (in dollars per share) | $ / shares	0
Forfeited (in dollars per share) | $ / shares	0
Ending balance, outstanding (in dollars per share) | $ / shares	55.60
Exercisable at end of period (in dollars per share) | $ / shares	$ 12.88
Weighted Average Remaining Contractual Term (years) and Aggregate Intrinsic Value
Outstanding contractual term	6 years 10 months 24 days
Exercisable contractual term	3 years
Outstanding aggregate intrinsic value | $	$ 3,504
Exercisable aggregate intrinsic value | $	$ 3,412

STOCKHOLDERS' EQUITY - Summar_2

STOCKHOLDERS' EQUITY - Summary of Restricted Stock Awards, Restricted Stock Unit and Performance-based Stock Unit Activity (Detail) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($) $ / shares shares
Performance Stock Unit
Weighted Average Remaining Contractual Term (years) and Aggregate Intrinsic Value
Percentage of attainment level (as a percent)	100%
Performance Stock Unit | Class A Common Stock
Weighted Average Remaining Contractual Term (years) and Aggregate Intrinsic Value
Number of additional shares (in shares)	159
Restricted Stock Awards, Restricted Stock Units And Performance Stock Units
Restricted Stock, Restricted Stock Units, and Performance Stock Units
Outstanding, beginning of period (in shares)	169
Granted (in shares)	89
Forfeited (in shares)	(2)
Outstanding, end of period (in shares)	206
Weighted Average Grant Date Fair Value
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 75.52
Granted (in dollars per share) | $ / shares	79.46
Forfeited (in dollars per share) | $ / shares	70.28
Outstanding at end of period (in dollars per share) | $ / shares	$ 81.16
Weighted Average Remaining Contractual Term (years) and Aggregate Intrinsic Value
Contractual term (in years)	2 years 2 months 12 days
Aggregate intrinsic value | $	$ 16,988
Restricted Stock Awards, Restricted Stock Units And Performance Stock Units | Class A Common Stock
Restricted Stock, Restricted Stock Units, and Performance Stock Units
Vested (in shares)	(50)
Weighted Average Grant Date Fair Value
Class A Common Stock Vested (in dollars per share) | $ / shares	$ 59.68
Unvested | Restricted Stock Awards, Restricted Stock Units And Performance Stock Units
Restricted Stock, Restricted Stock Units, and Performance Stock Units
Outstanding, end of period (in shares)	365
Weighted Average Grant Date Fair Value
Outstanding at end of period (in dollars per share) | $ / shares	$ 82.68
Weighted Average Remaining Contractual Term (years) and Aggregate Intrinsic Value
Contractual term (in years)	2 years
Aggregate intrinsic value | $	$ 30,201

STOCKHOLDERS' EQUITY - Summar_3

STOCKHOLDERS' EQUITY - Summary of Changes in Balances of Each Component of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 497,900	$ 422,457
Other comprehensive (loss) income, net of tax	(1,769)	6,143
Ending balance	501,655	$ 435,050
Accumulated gain (loss), cash flow hedge
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	7,542
Other comprehensive income	(1,336)
Amounts reclassified from accumulated other comprehensive income	(1,106)
Income tax benefit related to items of other comprehensive loss	673
Other comprehensive (loss) income, net of tax	(1,769)
Ending balance	$ 5,773

STOCKHOLDERS' EQUITY - Summar_4

STOCKHOLDERS' EQUITY - Summary of Reclassifications Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ 6,959	$ 5,204
Income before income taxes	4,339	5,148
Provision for income taxes	791	958
Net income	3,548	4,190
Accumulated gain (loss), cash flow hedge | Amounts Reclassified Out of Accumulated Other Comprehensive Income, Net of Tax
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	1,106	(1,128)
Provision for income taxes	303	(190)
Net income	803	(938)
Interest rate swaps | Accumulated gain (loss), cash flow hedge | Amounts Reclassified Out of Accumulated Other Comprehensive Income, Net of Tax
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ (1,106)	$ 1,128

EARNINGS PER SHARE (Details)

EARNINGS PER SHARE (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Numerator:
Net income	$ 3,548	$ 4,190
Denominators:
Unvested restricted stock (in shares)	(1,000)	(2,000)
Effect of weighted average shares outstanding (in shares)	(115,000)	(146,000)
Weighted average common shares outstanding, basic (in shares)	51,770,000	51,490,000
Impact of potentially dilutive securities:
Dilutive effect of stock options and other stock awards (in shares)	99,000	167,000
Weighted average common shares outstanding, diluted	51,869,000	51,657,000
Anti-dilutive potentially issuable shares (in shares)	126,000	78,000
Class A Common Stock
Denominators:
Common stock, shares outstanding (in shares)	50,898,000	50,650,000	50,704,000
Class B Common Stock
Denominators:
Common stock, shares outstanding (in shares)	988,000	988,000	988,000

OTHER ITEMS AND CHARGES (Detail

OTHER ITEMS AND CHARGES (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Unusual or Infrequent Items, or Both [Abstract]
Expense from acquisition activities	$ 2,863	$ 2,043

FAIR VALUE OF FINANCIAL INSTR_3

FAIR VALUE OF FINANCIAL INSTRUMENTS - Recurring Fair Value Measurements (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Assets:
Restricted investment securities - landfill closure	$ 1,972		$ 1,900
Liabilities:
Derivative Asset, Statement Of Financial Position Extensible Enumeration, Not Disclosed Flag	Interest rate swaps	Interest rate swaps
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Interest rate swaps	$ 0		0
Total assets	1,972		1,900
Liabilities:
Contingent consideration - acquisition	0		0
Interest rate swaps	0
Total	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Landfill
Assets:
Restricted investment securities - landfill closure	1,972		1,900
Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Interest rate swaps	10,100		11,806
Total assets	10,100		11,806
Liabilities:
Contingent consideration - acquisition	0		0
Interest rate swaps	736
Total	736
Recurring | Significant Other Observable Inputs (Level 2) | Landfill
Assets:
Restricted investment securities - landfill closure	0		0
Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Interest rate swaps	0		0
Total assets	0		0
Liabilities:
Contingent consideration - acquisition	376		965
Interest rate swaps	0
Total	376
Recurring | Significant Unobservable Inputs (Level 3) | Landfill
Assets:
Restricted investment securities - landfill closure	$ 0		$ 0

FAIR VALUE OF FINANCIAL INSTR_4

FAIR VALUE OF FINANCIAL INSTRUMENTS - Additional Information (Detail) - USD ($)	Mar. 31, 2023	Dec. 31, 2022
Term loan A facility ("Term Loan Facility") due December 2026; bearing interest at term secured overnight financing rate ("Term SOFR") plus 1.135% | Secured Debt
Debt Instrument [Line Items]
Principal amount of debt	$ 350,000,000	$ 350,000,000
Fair Value | Fixed Rate Bonds
Debt Instrument [Line Items]
Fixed rate debt	186,760,000
Carrying Value
Debt Instrument [Line Items]
Revolving credit facility	0
Carrying Value | Fixed Rate Bonds
Debt Instrument [Line Items]
Fixed rate debt	$ 197,000,000

SEGMENT REPORTING - Summary of

SEGMENT REPORTING - Summary of Financial Information by Reportable Segment (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Segment Reporting Information [Line Items]
Revenues	$ 262,595	$ 234,027
Depreciation and amortization	33,435	29,428
Operating income (loss)	10,265	10,168
Total assets	1,419,890	1,306,971	$ 1,449,215
Operating | Eastern
Segment Reporting Information [Line Items]
Revenues	83,909	71,319
Depreciation and amortization	11,903	11,450
Operating income (loss)	2,139	(2,229)
Total assets	364,872	355,371
Operating | Western
Segment Reporting Information [Line Items]
Revenues	111,034	95,839
Depreciation and amortization	17,665	14,659
Operating income (loss)	12,426	9,263
Total assets	744,084	684,969
Operating | Resource Solutions
Segment Reporting Information [Line Items]
Revenues	67,652	66,869
Depreciation and amortization	3,076	2,762
Operating income (loss)	(1,943)	3,691
Total assets	195,028	176,128
Corporate Entities
Segment Reporting Information [Line Items]
Revenues	0	0
Depreciation and amortization	791	557
Operating income (loss)	(2,357)	(557)
Total assets	115,906	90,503
Inter-company revenues
Segment Reporting Information [Line Items]
Revenues	(59,415)	(49,939)
Inter-company revenues | Eastern
Segment Reporting Information [Line Items]
Revenues	(19,369)	(16,668)
Inter-company revenues | Western
Segment Reporting Information [Line Items]
Revenues	(36,559)	(32,493)
Inter-company revenues | Resource Solutions
Segment Reporting Information [Line Items]
Revenues	$ (3,487)	$ (778)

SEGMENT REPORTING - Summary o_2

SEGMENT REPORTING - Summary of Revenues Attributable to Services Provided by Company (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Revenue from External Customer [Line Items]
Revenues	$ 262,595	$ 234,027
Solid waste operations
Revenue from External Customer [Line Items]
Revenues	194,943	167,158
Collection
Revenue from External Customer [Line Items]
Revenues	139,977	119,531
Disposal
Revenue from External Customer [Line Items]
Revenues	51,466	43,153
Power generation
Revenue from External Customer [Line Items]
Revenues	1,924	2,654
Processing
Revenue from External Customer [Line Items]
Revenues	1,576	1,820
Resource Solutions operations
Revenue from External Customer [Line Items]
Revenues	67,652	66,869
Processing
Revenue from External Customer [Line Items]
Revenues	22,806	27,395
National Accounts
Revenue from External Customer [Line Items]
Revenues	$ 44,846	$ 39,474