Casella Waste Systems (CWST) 10-Q 28 Jul 23 2023 Q2 Quarterly report Financial data

COVER

COVER - shares	6 Months Ended
	Jun. 30, 2023	Jul. 15, 2023
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 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	Q2
Amendment Flag	false
Class A Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		56,974,049
Class B Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		988,200

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
CURRENT ASSETS:
Cash and cash equivalents	$ 465,715	$ 71,152
Accounts receivable, net of allowance for credit losses of $3,333 and $3,016, respectively	117,682	100,886
Refundable income taxes	3,726	0
Prepaid expenses	18,122	15,182
Inventory	16,784	13,472
Other current assets	7,358	6,787
Total current assets	629,387	207,479
Property, plant and equipment, net of accumulated depreciation and amortization of $1,117,946 and $1,064,756, respectively	818,242	720,550
Operating lease right-of-use assets	104,920	92,063
Goodwill	619,683	274,458
Intangible assets, net	187,148	91,783
Restricted assets	2,005	1,900
Cost method investments	10,967	10,967
Deferred income taxes	16,408	22,903
Other non-current assets	28,532	27,112
Total assets	2,417,292	1,449,215
CURRENT LIABILITIES:
Current maturities of debt	32,747	8,968
Current operating lease liabilities	8,510	7,000
Accounts payable	87,602	74,203
Accrued payroll and related expenses	14,847	23,556
Accrued interest	3,116	2,858
Contract liabilities	16,260	3,742
Current accrued final capping, closure and post-closure costs	10,767	11,036
Other accrued liabilities	45,333	46,237
Total current liabilities	219,182	177,600
Debt, less current portion	983,344	585,015
Operating lease liabilities, less current portion	71,039	57,345
Accrued final capping, closure and post-closure costs, less current portion	107,949	102,642
Deferred income taxes	479	437
Other long-term liabilities	26,916	28,276
COMMITMENTS AND CONTINGENCIES
STOCKHOLDERS' EQUITY:
Additional paid-in capital	1,163,077	661,761
Accumulated deficit	(162,882)	(171,920)
Accumulated other comprehensive income, net of tax	7,608	7,542
Total stockholders' equity	1,008,383	497,900
Total liabilities and stockholders' equity	2,417,292	1,449,215
Class A Common Stock
STOCKHOLDERS' EQUITY:
Common stock	570	507
Class B Common Stock
STOCKHOLDERS' EQUITY:
Common stock	$ 10	$ 10

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2023 USD ($) vote $ / shares shares	Dec. 31, 2022 USD ($) vote $ / shares shares
Accounts receivable - trade, allowance for credit losses | $	$ 3,333	$ 3,016
Accumulated depreciation and amortization | $	$ 1,117,946	$ 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)	56,974,000	50,704,000
Common stock, shares outstanding (in shares)	56,974,000	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		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Income Statement [Abstract]
Revenues	$ 289,645	$ 283,666	$ 552,241	$ 517,693
Operating expenses:
Cost of operations	186,319	186,038	366,563	348,493
General and administration	35,865	33,562	71,544	63,354
Depreciation and amortization	34,924	31,150	68,359	60,579
Legal settlement	6,150	0	6,150	0
Expense from acquisition activities	3,677	1,019	6,540	3,062
Southbridge Landfill closure charge	96	178	206	318
Total operating expenses	267,031	251,947	519,362	475,806
Operating income	22,614	31,719	32,879	41,887
Other expense (income):
Interest income	(1,611)	(42)	(2,295)	(81)
Interest expense	9,001	5,698	15,959	10,902
Loss from termination of bridge financing	8,198	0	8,198	0
Other income	(452)	(312)	(800)	(457)
Other expense, net	15,136	5,344	21,062	10,364
Income before income taxes	7,478	26,375	11,817	31,523
Provision for income taxes	1,988	8,579	2,779	9,537
Net income	$ 5,490	$ 17,796	$ 9,038	$ 21,986
Basic earnings per share attributable to common stockholders:
Weighted average common shares outstanding, basic (in shares)	52,885	51,642	52,331	51,567
Basic earnings per common share (in dollars per share)	$ 0.10	$ 0.34	$ 0.17	$ 0.43
Diluted earnings per share attributable to common stockholders:
Weighted average common shares outstanding, diluted (in shares)	52,980	51,781	52,427	51,720
Diluted earnings per common share (in dollars per share)	$ 0.10	$ 0.34	$ 0.17	$ 0.43

UNAUDITED CONSOLIDATED STATEM_2

UNAUDITED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 5,490	$ 17,796	$ 9,038	$ 21,986
Hedging activity:
Interest rate swap settlements	1,290	(932)	2,345	(2,095)
Interest rate swap amounts reclassified into interest expense	(1,270)	994	(2,376)	2,122
Unrealized gain resulting from changes in fair value of derivative instruments	2,508	3,488	117	11,869
Other comprehensive income, before tax	2,528	3,550	86	11,896
Income tax provision related to items of other comprehensive income	693	570	20	2,773
Other comprehensive income, net of tax	1,835	2,980	66	9,123
Comprehensive income	$ 7,325	$ 20,776	$ 9,104	$ 31,109

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		988,000
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]
Net income (loss)	21,986
Hedging activity	9,123
Ending balance at Jun. 30, 2022	457,566	656,042	(203,013)	4,020		$ 507		$ 10
Ending balance (in shares) at Jun. 30, 2022					50,690,000	50,690,000	988,000	988,000
Beginning balance at Mar. 31, 2022	435,050	654,303	(220,809)	1,040		$ 506		$ 10
Beginning balance (in shares) at Mar. 31, 2022						50,650,000		988,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances of Class A common stock	803	802				$ 1
Issuance of Class A common stock (in shares)						40,000
Stock-based compensation	937	937
Net income (loss)	17,796		17,796
Hedging activity	2,980			2,980
Ending balance at Jun. 30, 2022	457,566	656,042	(203,013)	4,020		$ 507		$ 10
Ending balance (in shares) at Jun. 30, 2022					50,690,000	50,690,000	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		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]
Net income (loss)	9,038
Hedging activity	66
Ending balance at Jun. 30, 2023	1,008,383	1,163,077	(162,882)	7,608		$ 570		$ 10
Ending balance (in shares) at Jun. 30, 2023					56,974,000	56,974,000	988,000	988,000
Beginning balance at Mar. 31, 2023	501,655	663,735	(168,372)	5,773		$ 509		$ 10
Beginning balance (in shares) at Mar. 31, 2023						50,898,000		988,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A common stock - equity offering, net of stock issuance costs	496,238	496,177				$ 61
Issuance of Class A common stock - equity offering, net of stock issuance costs (in shares)						6,053,000
Issuances of Class A common stock	799	799
Issuance of Class A common stock (in shares)						23,000
Stock-based compensation	2,366	2,366
Net income (loss)	5,490		5,490
Hedging activity	1,835			1,835
Ending balance at Jun. 30, 2023	$ 1,008,383	$ 1,163,077	$ (162,882)	$ 7,608		$ 570		$ 10
Ending balance (in shares) at Jun. 30, 2023					56,974,000	56,974,000	988,000	988,000

UNAUDITED CONSOLIDATED STATEM_4

UNAUDITED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Cash Flows from Operating Activities:
Net income	$ 9,038	$ 21,986
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	68,359	60,579
Interest accretion on landfill and environmental remediation liabilities	5,001	4,015
Amortization of debt issuance costs	1,505	924
Stock-based compensation	4,341	3,178
Operating lease right-of-use assets expense	6,872	6,824
Disposition of assets, other items and charges, net	(300)	376
Loss from termination of bridge financing	8,198	0
Deferred income taxes	1,952	7,156
Changes in assets and liabilities, net of effects of acquisitions and divestitures:
Accounts receivable	(3,958)	(14,667)
Landfill operating lease contract expenditures	(1,318)	(1,308)
Accounts payable	8,898	10,142
Prepaid expenses, inventories and other assets	(5,845)	(6,099)
Accrued expenses, contract liabilities and other liabilities	(19,547)	(855)
Net cash provided by operating activities	83,196	92,251
Cash Flows from Investing Activities:
Acquisitions, net of cash acquired	(547,587)	(56,250)
Additions to property, plant and equipment	(50,415)	(54,868)
Proceeds from sale of property and equipment	776	507
Net cash used in investing activities	(597,226)	(110,611)
Cash Flows from Financing Activities:
Proceeds from debt borrowings	430,000	82,200
Principal payments on debt	(10,625)	(55,297)
Payments of debt issuance costs	(7,185)	(1,229)
Payments of contingent consideration	0	(1,000)
Proceeds from the exercise of share based awards	0	192
Proceeds from the public offering of Class A common stock	496,403	0
Net cash provided by financing activities	908,593	24,866
Net increase in cash and cash equivalents	394,563	6,506
Cash and cash equivalents, beginning of period	71,152	33,809
Cash and cash equivalents, end of period	465,715	40,315
Supplemental Disclosure of Cash Flow Information:
Cash interest payments	14,196	9,648
Cash income tax payments	7,913	2,092
Non-current assets obtained through long-term financing obligations	4,715	4,190
Right-of-use assets obtained in exchange for operating lease obligations	$ 17,756	$ 5,194

BASIS OF PRESENTATION

BASIS OF PRESENTATION	6 Months Ended
	Jun. 30, 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. Through June 30, 2023, we provided integrated solid waste services in seven states: Vermont, New Hampshire, New York, Massachusetts, Connecticut, Maine and Pennsylvania, with our headquarters located in Rutland, Vermont. On June 30, 2023, we acquired the equity interests of four wholly owned subsidiaries of GFL Environmental Inc. ("GFL Subsidiaries"), which are the basis of a newly formed regional operating segment, the Mid-Atlantic region, that will expand our integrated solid waste services into the states of Delaware and Maryland ("GFL Acquisition"). See Note 4, Business Combinations for further disclosure. Operations under the Mid-Atlantic region did not commence until July 1, 2023, and have had no impact on our operational results for the periods presented in this Quarterly Report on Form 10-Q. The GFL Acquisition was funded from financing transactions, see Note 7, Debt for further disclosure, the net proceeds from an equity offering, completed June 16, 2023, see Note 9, Stockholders' Equity for further disclosure, and cash on hand. We manage our solid waste operations on a geographic basis through regional operating segments, the Eastern, Western and Mid-Atlantic 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 and six months ended June 30, 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. 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 June 30, 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 June 30, 2023 through the date of this filing that would require recognition or disclosure in our consolidated financial statements.

ACCOUNTING CHANGES

ACCOUNTING CHANGES	6 Months Ended
	Jun. 30, 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. 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 quarter ended March 31, 2023, we elected optional expedients under this guidance that allowed us 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, the second amendment, dated as of February 9, 2023, and the third amendment, dated as of April 25, 2023, collectively with the specified acquisition loan joinder ("Loan Joinder") (the "Amended and Restated Credit Agreement") until we transitioned our interest rate derivative agreements from LIBOR to term secured overnight financing rate ("Term SOFR") in the three months ended June 30, 2023, See Note 7, Debt . This guidance will be in effect through December 31, 2024.

REVENUE RECOGNITION

REVENUE RECOGNITION	6 Months Ended
	Jun. 30, 2023
Revenue from Contract with Customer [Abstract]
REVENUE RECOGNITION	REVENUE RECOGNITION 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. 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 and six months ended June 30, 2023 and 2022: Three Months Ended June 30, 2023 Eastern Western Mid-Atlantic (1) Resource Solutions Total Revenues Collection $ 64,749 $ 85,099 $ — $ — $ 149,848 Landfill 7,220 18,921 — — 26,141 Transfer station 17,698 14,728 — — 32,426 Transportation 1,208 3,854 — — 5,062 Landfill gas-to-energy 173 1,148 — — 1,321 Processing 2,275 479 — 25,383 28,137 National Accounts — — — 46,710 46,710 Total revenues $ 93,323 $ 124,229 $ — $ 72,093 $ 289,645 Transferred at a point-in-time $ 99 $ 690 $ — $ 8,135 $ 8,924 Transferred over time 93,224 123,539 — 63,958 280,721 Total revenues $ 93,323 $ 124,229 $ — $ 72,093 $ 289,645 Three Months Ended June 30, 2022 Eastern Western Mid-Atlantic (1) Resource Solutions Total Revenues Collection $ 59,299 $ 77,962 $ — $ — $ 137,261 Landfill 6,542 18,599 — — 25,141 Transfer station 17,292 11,982 — — 29,274 Transportation 1,765 4,024 — — 5,789 Landfill gas-to-energy 249 1,504 — — 1,753 Processing 2,116 813 — 33,867 36,796 National Accounts — — — 47,652 47,652 Total revenues $ 87,263 $ 114,884 $ — $ 81,519 $ 283,666 Transferred at a point-in-time $ 117 $ 517 $ — $ 18,813 $ 19,447 Transferred over time 87,146 114,367 — 62,706 264,219 Total revenues $ 87,263 $ 114,884 $ — $ 81,519 $ 283,666 Six Months Ended June 30, 2023 Eastern Western Mid-Atlantic (1) Resource Solutions Total Revenues Collection $ 125,858 $ 163,967 $ — $ — $ 289,825 Landfill 13,521 35,380 — — 48,901 Transfer 31,680 24,691 — — 56,371 Transportation 2,390 7,434 — — 9,824 Landfill gas-to-energy 386 2,859 — — 3,245 Processing 3,398 931 — 48,189 52,518 National Accounts — — — 91,557 91,557 Total revenues $ 177,233 $ 235,262 $ — $ 139,746 $ 552,241 Transferred at a point-in-time $ 218 $ 1,421 $ — $ 14,572 $ 16,211 Transferred over time 177,015 233,841 — 125,174 536,030 Total revenues $ 177,233 $ 235,262 $ — $ 139,746 $ 552,241 Six Months Ended June 30, 2022 Eastern Western Mid-Atlantic (1) Resource Solutions Total Revenues Collection $ 110,796 $ 145,997 $ — $ — $ 256,793 Landfill 11,918 32,788 — — 44,706 Transfer 28,905 19,825 — — 48,730 Transportation 3,238 6,682 — — 9,920 Landfill gas-to-energy 522 3,885 — — 4,407 Processing 3,203 1,546 — 61,263 66,012 National Accounts — — — 87,125 87,125 Total revenues $ 158,582 $ 210,723 $ — $ 148,388 $ 517,693 Transferred at a point-in-time $ 236 $ 1,028 $ — $ 33,900 $ 35,164 Transferred over time 158,346 209,695 — 114,488 482,529 Total revenues $ 158,582 $ 210,723 $ — $ 148,388 $ 517,693 (1) Operations under the Mid-Atlantic region did not commence until July 1, 2023, and have had no impact on our operational results for the periods presented in this Quarterly Report on Form 10-Q. 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 $6,329 and $12,958 in the three and six months ended June 30, 2023, respectively, and $5,908 and $9,702 in the three and six months ended June 30, 2022, respectively. Rebates are generally recorded as a reduction of revenues upon the sale of such materials, or upon receipt of the recycled materials at our facilities. We did not record revenues in the three and six months ended June 30, 2023 or June 30, 2022 from performance obligations satisfied in previous periods. Contract receivables, which are included in accounts receivable, net in our consolidated balance sheets 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 $119,971 and $102,234 as of June 30, 2023 and December 31, 2022, respectively. Certain customers are billed in advance and, accordingly, recognition of the related revenues for which payment has been received is deferred as a contract liability until the services are provided and control transferred to the customer. We recognized contract liabilities of $16,260 and $3,742 as of June 30, 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 six months ended June 30, 2023 and June 30, 2022, respectively, when the services were performed.

BUSINESS COMBINATIONS

BUSINESS COMBINATIONS	6 Months Ended
	Jun. 30, 2023
Business Combination and Asset Acquisition [Abstract]
BUSINESS COMBINATIONS	BUSINESS COMBINATIONS In June 2023, we entered into an asset purchase agreement with Consolidated Waste Services, LLC and its affiliates (dba as Twin Bridges), pursuant to which we agreed to acquire assets in the greater Albany, New York area for total consideration of approximately $219,000 ("Twin Bridges Acquisition"), subject to the terms and conditions set forth in the agreement. The Twin Bridges Acquisition includes two collection operations, one transfer station, one material recovery facility, one office building, and several satellite properties. The Twin Bridges Acquisition is subject to customary closing conditions, including the expiration or termination of any applicable waiting period under the Hart-Scott-Rodino Act, and the absence of any investigation by any governmental entity regarding the legality of the transactions contemplated by the asset purchase agreement. The waiting period under the Hart-Scott-Rodino Act has expired. On July 6, 2023, we received a subpoena duces tecum from the New York State Attorney General (“NYAG”) seeking information about the Twin Bridges Acquisition. We are cooperating with the NYAG to address the agency’s questions. The Twin Bridges Acquisition is expected to be funded with the net proceeds from an equity offering completed on June 16, 2023. See Note 9, Stockholders' Equity for further disclosure regarding the equity offering. In the six months ended June 30, 2023, we acquired two businesses: the GFL Acquisition, which includes solid waste collection, transfer and recycling operations in Pennsylvania, Maryland and Delaware whose assets are allocated between our Mid-Atlantic region and Resource Solutions operating segments, as well as a stand alone solid waste business in our Western region. In the six months ended June 30, 2022, we acquired eight businesses primarily related to our solid-waste operations, which included solid-waste collection, recycling, transfer station and transportation businesses. The operating results of these businesses are included in the accompanying unaudited consolidated statements of operations from each date of acquisition, with the exception of the GFL Acquisition whose operations did not commence until July 1, 2023, and the purchase price has been allocated to the net assets acquired based on fair values at each date of acquisition with the residual amounts recorded as goodwill. Purchase price allocations are based on information existing at the acquisition dates or upon closing the transactions, including contingent consideration. Acquired intangible assets other than goodwill that are subject to amortization include customer relationships, trade names and covenants not-to-compete. Such assets are amortized over a two-year to ten-year period from the date of acquisition. All amounts recorded to goodwill are expected to be deductible for tax purposes, with the exception of one of the GFL Subsidiaries acquired as a part of the GFL Acquisition in the six months ended June 30, 2023. A summary of the purchase price paid and the purchase price allocation for acquisitions follows: Six Months Ended 2023 2022 Purchase Price: Cash used in acquisitions, net of cash acquired $ 544,359 $ 55,053 Holdbacks to sellers and contingent consideration 1,900 3,842 Total consideration $ 546,259 $ 58,895 Allocated as follows: Current assets $ 15,364 $ 7,584 Property, plant and equipment: Land 2,213 2,804 Buildings and improvements 8,666 5,308 Machinery and equipment 90,276 6,712 Operating lease right-of-use assets 11,260 405 Intangible assets: Covenants not-to-compete 10,550 1,415 Customer relationships 93,000 9,725 Other non-current assets — 40 Deferred tax liability (5,160) — Current liabilities (15,195) (3,577) Operating lease liabilities, less current portion (9,887) (282) Fair value of assets acquired and liabilities assumed 201,087 30,134 Excess purchase price allocated to goodwill $ 345,172 $ 28,761 Certain purchase price allocations, including the GFL Acquisition which is subject to finalizing the third-party valuation, are preliminary and are based on information existing at the acquisition dates or upon closing the transaction. Accordingly, the purchase price allocations are subject to change. Unaudited pro forma combined information that shows our operational results as though each acquisition completed since the beginning of the prior fiscal year had occurred as of January 1, 2022 is as follows: Three Months Ended Six Months Ended 2023 2022 2023 2022 Revenues $ 335,363 $ 335,299 $ 645,821 $ 626,980 Operating income $ 25,982 $ 35,543 $ 39,734 $ 50,250 Net income $ 7,494 $ 19,985 $ 13,113 $ 26,421 Basic earnings per share attributable to common stockholders: Weighted average common shares outstanding 52,885 51,642 52,331 51,567 Basic earnings per common share $ 0.14 $ 0.39 $ 0.25 $ 0.51 Diluted earnings per share attributable to common stockholders: Weighted average common shares outstanding 52,980 51,781 52,427 51,720 Diluted earnings per common share $ 0.14 $ 0.39 $ 0.25 $ 0.51 The unaudited pro forma results set forth in the table above have been prepared for comparative purposes only and are not necessarily indicative of the actual results of operations had the acquisitions occurred as of January 1, 2022 or of the results of our future operations. Furthermore, the unaudited pro forma results do not give effect to all cost savings or incremental costs that may occur as the result of the integration and consolidation of the completed acquisitions.

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS	6 Months Ended
	Jun. 30, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND INTANGIBLE ASSETS	GOODWILL AND INTANGIBLE ASSETS A summary of the activity and balances related to goodwill by operating segment is as follows: December 31, Acquisitions Measurement Period Adjustments June 30, Eastern $ 52,406 $ — $ — $ 52,406 Western 183,286 11,282 53 194,621 Mid-Atlantic — 333,890 — 333,890 Resource Solutions 38,766 — — 38,766 $ 274,458 $ 345,172 $ 53 $ 619,683 Summaries of intangible assets by type follows: Covenants Customer Relationships Trade Names Total Balance, June 30, 2023 Intangible assets $ 41,863 $ 220,179 $ 8,405 $ 270,447 Less accumulated amortization (25,065) (52,333) (5,901) (83,299) $ 16,798 $ 167,846 $ 2,504 $ 187,148 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 $4,226 and $8,296 during the three and six months ended June 30, 2023, respectively, and $4,262 and $8,052 during the three and six months ended June 30, 2022, respectively. 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 June 30, 2023 Fiscal year ending December 31, 2023 $ 17,546 Fiscal year ending December 31, 2024 $ 33,668 Fiscal year ending December 31, 2025 $ 30,935 Fiscal year ending December 31, 2026 $ 27,532 Fiscal year ending December 31, 2027 $ 24,353 Thereafter $ 53,114

ACCRUED FINAL CAPPING, CLOSURE

ACCRUED FINAL CAPPING, CLOSURE AND POST CLOSURE	6 Months Ended
	Jun. 30, 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: Six Months Ended 2023 2022 Beginning balance $ 113,678 $ 86,914 Obligations incurred 2,615 2,244 Revision in estimates (1) — 1,443 Accretion expense 4,809 3,799 Obligations settled (2) (2,386) (2,027) Ending balance $ 118,716 $ 92,373 (1) Relates to a change in estimates concerning anticipated capping costs at one of our landfills. (2) May include amounts that are being processed through accounts payable as a part of our disbursements cycle.

DEBT

DEBT	6 Months Ended
	Jun. 30, 2023
Debt And Derivatives Disclosure [Abstract]
DEBT	DEBT A summary of debt is as follows: June 30, December 31, Senior Secured Credit Facility: Term loan A facility ("Term Loan Facility") due December 2026; bearing interest at Term SOFR plus 1.135% $ 350,000 $ 350,000 Term loan A facility ("2023 Term Loan Facility") due December 2026; bearing interest at Term SOFR plus 2.385% 430,000 — 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 ending in 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 ending in 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 ending in 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 ending in 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 ending in 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 ending in 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 ending in 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 ending in 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 ending in 2029; bearing interest at 2.95% 11,000 11,000 Other: Finance leases 50,228 49,813 Notes payable maturing through March 2025; bearing interest up to 8.1% 339 664 Principal amount of debt 1,027,567 603,477 Less—unamortized debt issuance costs (1) 11,476 9,494 Debt less unamortized debt issuance costs 1,016,091 593,983 Less—current maturities of debt 32,747 8,968 $ 983,344 $ 585,015 (1) A summary of unamortized debt issuance costs by debt instrument follows: June 30, December 31, Revolving Credit Facility, Term Loan Facility and 2023 Term Loan Facility (collectively, the "Credit Facility") $ 7,087 $ 4,716 New York Bonds 2014R-1 832 866 New York Bonds 2014R-2 177 207 New York Bonds 2020 1,016 1,106 FAME Bonds 2005R-3 134 176 FAME Bonds 2015R-1 309 344 FAME Bonds 2015R-2 156 193 Vermont Bonds 2013 351 378 Vermont Bonds 2022A-1 1,079 1,144 New Hampshire Bonds 335 364 $ 11,476 $ 9,494 Financing Activities In the quarter ended March 31, 2023, we entered into first and second amendments to our Amended and Restated Credit Agreement. The first amendment provides, commencing in the fiscal year ending December 31, 2024, that 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 the prior fiscal year: (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 or minus any sustainable rate adjustment plus an applicable interest rate margin based upon our consolidated net leverage ratio. In April 2023, we entered into an equity purchase agreement pursuant to which we agreed to the GFL Acquisition. In connection with the GFL Acquisition, we entered into (i) a commitment letter to obtain short-term secured bridge financing of up to $375,000 and (ii) the third amendment to the Amended and Restated Credit Agreement to, among other things, permit the draw down of the short-term secured bridge financing and authorize a delayed draw term loan facility to be executed with customary limited condition provisions. The short-term secured bridge financing was undrawn and subsequently terminated in May 2023 when we entered into the Loan Joinder, which provided for a $430,000 aggregate principal amount 2023 Term Loan Facility under the Amended and Restated Credit Agreement. In June 2023, we borrowed $430,000 under the 2023 Term Loan Facility and paid certain fees and costs due and payable in connection therewith. Borrowings from the 2023 Term Loan Facility were used to fund, in conjunction with cash and cash equivalents and borrowings from our Revolving Credit Facility, the GFL Acquisition. In June 2023, we entered into an asset purchase agreement pursuant to which we agreed to the Twin Bridges Acquisition, which is pending regulatory approval. In connection with the Twin Bridges Acquisition, we entered into a commitment letter to obtain short-term unsecured bridge financing of up to $200,000 that was undrawn and subsequently terminated when we completed the public offering of our Class A common stock on June 16, 2023. See Note 9, Stockholders' Equity for further disclosure regarding the public offering. As of June 30, 2023, we have accrued $4,580 in our current liabilities for the unpaid portion of unsecured bridge financing costs. Credit Facility As of June 30, 2023, we are party to the Amended and Restated Credit Agreement, which provides for a $350,000 aggregate principal amount Term Loan Facility, a $300,000 Revolving Credit Facility, with a $75,000 sublimit for letters of credit, and a $430,000 2023 Term Loan Facility. 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 further increase based on 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. The Credit Facility 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 or minus any sustainable rate adjustment of up to positive or negative 4.0 basis points per annum, plus an applicable interest rate margin based upon our consolidated net leverage ratio as follows: Term SOFR Loans Base Rate Loans Term Loan Facility 1.125% to 2.125% 0.125% to 1.125% Revolving Credit Facility 1.125% to 2.125% 0.125% to 1.125% 2023 Term Loan Facility 1.625% to 2.625% 0.625% to 1.625% A commitment fee will be charged on undrawn amounts at a rate of 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 0.20% to 0.40% per annum, plus a sustainability adjustment of up to positive or negative 1.0 basis point per annum. The Amended and Restated Credit Agreement provides that Term SOFR is subject to a zero percent floor. 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 June 30, 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 June 30, 2023 no amount had been drawn. Interest Expense The components of interest expense are as follows: Three Months Ended Six Months Ended 2023 2022 2023 2022 Interest expense on long-term debt and finance leases $ 8,007 $ 5,189 $ 14,437 $ 9,823 Amortization of debt issuance costs (1) 1,004 468 1,505 924 Letter of credit fees 98 116 194 230 Less: capitalized interest (108) (75) (177) (75) Total interest expense $ 9,001 $ 5,698 $ 15,959 $ 10,902 (1) Includes interest expense related to short-term secured bridge financing entered into in connection with the GFL Acquisition of $395 and $395 during the three and six months ended June 30, 2023, respectively, and interest expense related to short-term unsecured financing entered into in connection with the Twin Bridges Acquisition, which is pending regulatory approval, of $101 and $101 during the three and six months ended June 30, 2023, respectively. Loss from Termination of Bridge Financing In the three and six months ended June 30, 2023, we wrote-off the unamortized debt issuance costs and recognized a loss from termination of bridge financing upon the extinguishment of both a secured bridge financing agreement in connection with the GFL Acquisition of $3,718 and $3,718, respectively, and an unsecured bridge financing agreement in connection with the Twin Bridges Acquisition, which is pending regulatory approval, of $4,480 and $4,480, respectively. 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. In July 2023, we entered into interest rate derivative agreements with a notional amount of $250,000 after increasing the variable rate portion of our long-term debt by $430,000 by entering into the 2023 Term Loan Facility. According to the terms of the agreements, we receive interest based on Term SOFR restricted by a 0.0% floor, and pay interest at a rate of 4.285%. The agreements became effective in July 2023 and mature in June 2028. As of June 30, 2023, we had active interest rate derivative agreements with a total notional amount of $165,000. According to the terms of the agreements, we receive interest based on Term SOFR, restricted by a 0.0% floor, and pay interest at a weighted average rate of approximately 2.08%. The agreements mature between February 2026 and May 2028. As of December 31, 2022, we had active interest rate derivative agreements with a total notional amount of $190,000 and 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 June 30, December 31, Interest rate swaps Other current assets $ 5,147 $ 4,345 Interest rate swaps Other non-current assets 6,763 7,461 $ 11,910 $ 11,806 Interest rate swaps Other long-term liabilities $ 18 $ — Interest rate swaps Accumulated other comprehensive income, net of tax $ 11,892 $ 11,806 Interest rate swaps - tax effect Accumulated other comprehensive income, net of tax (4,284) (4,264) $ 7,608 $ 7,542

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	6 Months Ended
	Jun. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Legal Proceedings In the ordinary course of our business and as the 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 $6,208 relating to our outstanding legal proceedings as of June 30, 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. See Note 11, Other Items and Charges for disclosure regarding a legal settlement charge accrued for as of June 30, 2023 due to reaching an agreement at a mediation held on June 20, 2023 and later executed on July 24, 2023. North Country Environmental Services Expansion Permit The permit for expansion of the Bethlehem, New Hampshire landfill of our subsidiary, North Country Environmental Services, Inc. (“NCES”), known as “Stage VI”, issued in October 2020 (“Permit”), was appealed by the Conservation Law Foundation (“CLF”) to the New Hampshire Waste Management Council (“Council”) on November 9, 2020 on the grounds it failed to meet the public benefit criteria. Following a hearing on the merits during which the Council found that the New Hampshire Department of Environmental Services (“DES”) had reasonably measured and acted lawfully in determining a capacity need for Stage VI, the hearing officer presiding over the proceedings issued an Order on May 11, 2022, without further hearing, determining instead that DES had acted unlawfully in reaching these conclusions (“Hearing Officer’s Order”), and remanded the Permit to DES on this determination. On December 5, 2022, DES and NCES both separately sought review of the Hearing Officer’s Order on appeal to the New Hampshire Supreme Court (“Supreme Court”). On December 14, 2022, NCES filed an action 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 in that the Council did not hold a public meeting to deliberate on the Hearing Officer’s Order. The Superior Court has since dismissed that proceeding, however, NCES appealed that decision to the Supreme Court on April 18, 2023. Both Supreme Court appeals remain pending. On September 20, 2022, NCES, which has since withdrawn as a party, and our subsidiary, Granite State Landfill, LLC, filed a Petition for Declaratory Judgment ("Petition") in the Superior Court asking the Superior Court for a determination of the meaning and constitutionality of New Hampshire’s public benefit requirement, the same statute at issue in the Hearing Officer’s Order. This matter remains pending before the Superior Court. On April 12, 2023, DES issued approval of construction plans for Stage VI, Phase II to NCES (“DES Approval”). CLF appealed the DES Approval to the Council on May 11, 2023, on the grounds that it failed to meet the public benefit criteria, and that the DES Approval conflicts with the Hearing Officer’s May 11, 2022 Order determining that DES had acted unlawfully in issuing the Permit, and requested expedited review. The Council has denied the request for expedited review and this appeal remains pending before the Council. NCES will continue to vigorously defend the Permit through the appeals to the Supreme Court, will litigate the Petition before the Superior Court, and will defend the DES Approval on appeal before the Council. 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 the 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 June 30, 2023 range between 1.5% and 4.1%. A summary of the changes to the aggregate environmental remediation liabilities for the six months ended June 30, 2023 and 2022 follows: Six Months Ended 2023 2022 Beginning balance $ 6,335 $ 5,887 Accretion expense 51 54 Obligations settled (1) (320) (72) Ending balance 6,066 5,869 Less: current portion 1,430 280 Long-term portion $ 4,636 $ 5,589 (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	6 Months Ended
	Jun. 30, 2023
Equity [Abstract]
STOCKHOLDERS' EQUITY	STOCKHOLDERS' EQUITY Public Offering of Class A Common Stock On June 16, 2023, we completed a public offering of 6,053 shares of our Class A common stock at a public offering price of $85.50 per share. After deducting stock issuance costs received as of June 30, 2023, including underwriting discounts, commissions and offering expenses, the offering has resulted in net proceeds of $496,403. The net proceeds from this offering were and are to be used to fund acquisition activity, as discussed in Note 4, Business Combinations, to pay certain costs associated with acquisition activities, as discussed in Note 11, Other Items and Charges , and to repay borrowings and/or debt securities as discussed Note 7, Debt. 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 June 30, 2023, there were 640 Class A common stock equivalents available for future grant under the 2016 Plan. In the three months ended June 30, 2023, our stockholders approved the amendment and restatement of our Amended and Restated 1997 Employee Stock Purchase Plan (as further amended and restated, the"ESPP") to increase the number of shares of Class A common stock reserved for issuance under the ESPP by 400 shares of Class A common stock. As of June 30, 2023, 444 shares of Class A common stock were available for issuance under the ESPP. 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, June 30, 2023 129 $ 55.60 6.7 $ 4,512 Exercisable, June 30, 2023 49 $ 12.88 2.8 $ 3,793 Stock-based compensation expense related to stock options was $125 and $248 during the three and six months ended June 30, 2023, respectively, as compared to $17 and $33 during the three and six months ended June 30, 2022, respectively. As of June 30, 2023, we had $1,850 of unrecognized stock-based compensation expense related to outstanding stock options to be recognized over a weighted average period of 4.0 years. During the three and six months ended June 30, 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 98 $ 80.61 Class A Common Stock Vested (62) $ 62.22 Forfeited (2) $ 71.25 Outstanding, June 30, 2023 203 $ 82.11 1.9 $ 18,339 Unvested, June 30, 2023 362 $ 83.23 1.8 $ 32,798 (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 $2,132 and $3,894 during the three and six months ended June 30, 2023, respectively, as compared to $828 and $2,979 during the three and six months ended June 30, 2022, respectively. During the three and six months ended June 30, 2023, the total fair value of other stock awards vested was $1,094 and $5,056, respectively. As of June 30, 2023, total unrecognized stock-based compensation expense related to outstanding restricted stock awards was $17, which will be recognized over a weighted average period of 0.9 years. As of June 30, 2023, total unrecognized stock-based compensation expense related to outstanding restricted stock units was $5,905, which will be recognized over a weighted average period of 2.0 years. As of June 30, 2023, total expected unrecognized stock-based compensation expense related to outstanding performance stock units was $6,791 to be recognized over a weighted average period of 1.9 years. The weighted average fair value of market-based performance stock units granted during the six months ended June 30, 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 $109 and $199 of stock-based compensation expense related to the ESPP during the three and six months ended June 30, 2023, respectively, as compared to $93 and $166 during the three and six months ended June 30, 2022, respectively. 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 2,462 Amounts reclassified from accumulated other comprehensive income (2,376) Income tax provision related to items of other comprehensive income (20) Net current-period other comprehensive income, net of tax 66 Balance, June 30, 2023 $ 7,608 A summary of reclassifications out of accumulated other comprehensive income, net of tax into earnings follows: Three Months Ended Six Months Ended 2023 2022 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 $ (1,270) $ 994 $ (2,376) $ 2,122 Interest expense 1,270 (994) 2,376 (2,122) Income before income taxes 348 — 651 (190) Provision for income taxes $ 922 $ (994) $ 1,725 $ (1,932) Net income

EARNINGS PER SHARE

EARNINGS PER SHARE	6 Months Ended
	Jun. 30, 2023
Earnings Per Share [Abstract]
EARNINGS PER SHARE	EARNINGS PER SHARE Basic 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 Six Months Ended 2023 2022 2023 2022 Numerator: Net income $ 5,490 $ 17,796 $ 9,038 $ 21,986 Denominators: Number of shares outstanding, end of period: Class A common stock 56,974 50,690 56,974 50,690 Class B common stock 988 988 988 988 Unvested restricted stock (1) (2) (1) (2) Effect of weighted average shares outstanding (1) (5,076) (34) (5,630) (109) Basic weighted average common shares outstanding 52,885 51,642 52,331 51,567 Impact of potentially dilutive securities: Dilutive effect of stock options and other stock awards 95 139 96 153 Diluted weighted average common shares outstanding 52,980 51,781 52,427 51,720 Anti-dilutive potentially issuable shares 75 70 84 70 (1) Adjustments in the three and six months ended June 30, 2023 primarily associated with the 6,053 shares of Class A common stock issued as part of the public offering, completed on June 16, 2023, only being outstanding for 14 days in the periods ended June 30, 2023. See Note 9, Stockholders' Equity for disclosure regarding the public offering of Class A common stock.

OTHER ITEMS AND CHARGES

OTHER ITEMS AND CHARGES	6 Months Ended
	Jun. 30, 2023
Unusual or Infrequent Items, or Both [Abstract]
OTHER ITEMS AND CHARGES	OTHER ITEMS AND CHARGES Expense from Acquisition Activities In the three and six months ended June 30, 2023, we recorded charges of $3,677 and $6,540, respectively, and in the three and six months ended June 30, 2022, we recorded charges of $1,019 and $3,062, 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. Legal settlement In the three and six months ended June 30, 2023, we accrued for a charge of $6,150 in current liabilities due to reaching an agreement at a mediation held on June 20, 2023 with the collective class members of a class action lawsuit relating to certain claims under the Fair Labor Standards Act of 1938 as well as state wage and hours laws. The settlement agreement was executed July 24, 2023, and remains subject to court approval. See Note 8, Commitments and Contingencies for disclosure regarding our aggregate legal proceedings accrual.

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	6 Months Ended
	Jun. 30, 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 Term SOFR 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 June 30, 2023 Using: Quoted Prices in Significant Other Significant Assets: Restricted investment securities - landfill closure $ 2,005 $ — $ — Interest rate swaps — 11,910 — $ 2,005 $ 11,910 $ — Liabilities: Contingent consideration - acquisition $ — $ — $ 376 Interest rate swaps — 18 — $ — $ 18 $ 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 June 30, 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 $190,876 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 June 30, 2023, the carrying values of our Term Loan Facility and 2023 Term Loan Facility were $350,000 and $430,000, respectively, 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	6 Months Ended
	Jun. 30, 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, Western and Mid-Atlantic regions. The GFL Acquisition, which occurred on June 30, 2023 and is the basis for our newly formed Mid-Atlantic operating segment, did not commence operations until July 1, 2023 and, therefore, had no operational impact on the periods presented in this Quarterly Report on Form 10-Q. 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 eastern 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 June 30, 2023 Segment Outside Inter-company Depreciation and Operating Total Eastern $ 93,323 $ 23,563 $ 12,148 $ 7,519 $ 366,892 Western 124,229 42,342 18,917 18,991 751,324 Mid-Atlantic — — — — 550,758 Resource Solutions 72,093 3,316 3,090 688 203,049 Corporate Entities — — 769 (4,584) 545,269 Eliminations — (69,221) — — — $ 289,645 $ — $ 34,924 $ 22,614 $ 2,417,292 Three Months Ended June 30, 2022 Segment Outside Inter-company Depreciation and Operating Total Eastern $ 87,263 $ 22,147 $ 11,538 $ 6,150 $ 362,942 Western 114,884 39,491 15,939 19,897 697,252 Mid-Atlantic — — — — — Resource Solutions 81,519 317 3,110 6,235 189,820 Corporate Entities — — 563 (563) 120,705 Eliminations — (61,955) — — — $ 283,666 $ — $ 31,150 $ 31,719 $ 1,370,719 Six Months Ended June 30, 2023 Segment Outside Inter-company Depreciation and Operating Total Eastern $ 177,233 $ 42,932 $ 24,051 $ 9,659 $ 366,892 Western 235,262 78,901 36,583 31,417 751,324 Mid-Atlantic — — — — 550,758 Resource Solutions 139,746 6,803 6,166 (1,255) 203,049 Corporate Entities — — 1,559 (6,942) 545,269 Eliminations — (128,636) — — — $ 552,241 $ — $ 68,359 $ 32,879 $ 2,417,292 Six Months Ended June 30, 2022 Segment Outside Inter-company Depreciation and Operating Total Eastern $ 158,582 $ 38,815 $ 22,988 $ 3,920 $ 362,942 Western 210,723 71,983 30,598 29,160 697,252 Mid-Atlantic — — — — — Resource Solutions 148,388 1,095 5,872 9,928 189,820 Corporate Entities — — 1,121 (1,121) 120,705 Eliminations — (111,893) — — — $ 517,693 $ — $ 60,579 $ 41,887 $ 1,370,719 A summary of our revenues attributable to services provided follows: Three Months Ended Six Months Ended 2023 2022 2023 2022 Collection $ 149,848 $ 137,261 $ 289,825 $ 256,793 Disposal 63,629 60,204 115,096 103,356 Power generation 1,321 1,753 3,245 4,407 Processing 2,754 2,929 4,329 4,749 Solid waste operations 217,552 202,147 412,495 369,305 Processing 25,383 33,867 48,189 61,263 National Accounts 46,710 47,652 91,557 87,125 Resource Solutions operations 72,093 81,519 139,746 148,388 Total revenues $ 289,645 $ 283,666 $ 552,241 $ 517,693

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022
Pay vs Performance Disclosure
Net income	$ 5,490	$ 3,548	$ 17,796	$ 4,190	$ 9,038	$ 21,986

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Jun. 30, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

ACCOUNTING CHANGES (Policies)

ACCOUNTING CHANGES (Policies)	6 Months Ended
	Jun. 30, 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. Through June 30, 2023, we provided integrated solid waste services in seven states: Vermont, New Hampshire, New York, Massachusetts, Connecticut, Maine and Pennsylvania, with our headquarters located in Rutland, Vermont. On June 30, 2023, we acquired the equity interests of four wholly owned subsidiaries of GFL Environmental Inc. ("GFL Subsidiaries"), which are the basis of a newly formed regional operating segment, the Mid-Atlantic region, that will expand our integrated solid waste services into the states of Delaware and Maryland ("GFL Acquisition"). See Note 4, Business Combinations for further disclosure. Operations under the Mid-Atlantic region did not commence until July 1, 2023, and have had no impact on our operational results for the periods presented in this Quarterly Report on Form 10-Q. The GFL Acquisition was funded from financing transactions, see Note 7, Debt for further disclosure, the net proceeds from an equity offering, completed June 16, 2023, see Note 9, Stockholders' Equity for further disclosure, and cash on hand. We manage our solid waste operations on a geographic basis through regional operating segments, the Eastern, Western and Mid-Atlantic 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 and six months ended June 30, 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 June 30, 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 June 30, 2023 through the date of this filing that would require recognition or disclosure in our consolidated financial statements.
Accounting Standards Adopted and Pending Adoption	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. 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 quarter ended March 31, 2023, we elected optional expedients under this guidance that allowed us 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, the second amendment, dated as of February 9, 2023, and the third amendment, dated as of April 25, 2023, collectively with the specified acquisition loan joinder ("Loan Joinder") (the "Amended and Restated Credit Agreement") until we transitioned our interest rate derivative agreements from LIBOR to term secured overnight financing rate ("Term SOFR") in the three months ended June 30, 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 Term SOFR 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, Western and Mid-Atlantic regions. The GFL Acquisition, which occurred on June 30, 2023 and is the basis for our newly formed Mid-Atlantic operating segment, did not commence operations until July 1, 2023 and, therefore, had no operational impact on the periods presented in this Quarterly Report on Form 10-Q. 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 eastern 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)	6 Months Ended
	Jun. 30, 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. 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 quarter ended March 31, 2023, we elected optional expedients under this guidance that allowed us 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, the second amendment, dated as of February 9, 2023, and the third amendment, dated as of April 25, 2023, collectively with the specified acquisition loan joinder ("Loan Joinder") (the "Amended and Restated Credit Agreement") until we transitioned our interest rate derivative agreements from LIBOR to term secured overnight financing rate ("Term SOFR") in the three months ended June 30, 2023, See Note 7, Debt . This guidance will be in effect through December 31, 2024.

REVENUE RECOGNITION (Tables)

REVENUE RECOGNITION (Tables)	6 Months Ended
	Jun. 30, 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 and six months ended June 30, 2023 and 2022: Three Months Ended June 30, 2023 Eastern Western Mid-Atlantic (1) Resource Solutions Total Revenues Collection $ 64,749 $ 85,099 $ — $ — $ 149,848 Landfill 7,220 18,921 — — 26,141 Transfer station 17,698 14,728 — — 32,426 Transportation 1,208 3,854 — — 5,062 Landfill gas-to-energy 173 1,148 — — 1,321 Processing 2,275 479 — 25,383 28,137 National Accounts — — — 46,710 46,710 Total revenues $ 93,323 $ 124,229 $ — $ 72,093 $ 289,645 Transferred at a point-in-time $ 99 $ 690 $ — $ 8,135 $ 8,924 Transferred over time 93,224 123,539 — 63,958 280,721 Total revenues $ 93,323 $ 124,229 $ — $ 72,093 $ 289,645 Three Months Ended June 30, 2022 Eastern Western Mid-Atlantic (1) Resource Solutions Total Revenues Collection $ 59,299 $ 77,962 $ — $ — $ 137,261 Landfill 6,542 18,599 — — 25,141 Transfer station 17,292 11,982 — — 29,274 Transportation 1,765 4,024 — — 5,789 Landfill gas-to-energy 249 1,504 — — 1,753 Processing 2,116 813 — 33,867 36,796 National Accounts — — — 47,652 47,652 Total revenues $ 87,263 $ 114,884 $ — $ 81,519 $ 283,666 Transferred at a point-in-time $ 117 $ 517 $ — $ 18,813 $ 19,447 Transferred over time 87,146 114,367 — 62,706 264,219 Total revenues $ 87,263 $ 114,884 $ — $ 81,519 $ 283,666 Six Months Ended June 30, 2023 Eastern Western Mid-Atlantic (1) Resource Solutions Total Revenues Collection $ 125,858 $ 163,967 $ — $ — $ 289,825 Landfill 13,521 35,380 — — 48,901 Transfer 31,680 24,691 — — 56,371 Transportation 2,390 7,434 — — 9,824 Landfill gas-to-energy 386 2,859 — — 3,245 Processing 3,398 931 — 48,189 52,518 National Accounts — — — 91,557 91,557 Total revenues $ 177,233 $ 235,262 $ — $ 139,746 $ 552,241 Transferred at a point-in-time $ 218 $ 1,421 $ — $ 14,572 $ 16,211 Transferred over time 177,015 233,841 — 125,174 536,030 Total revenues $ 177,233 $ 235,262 $ — $ 139,746 $ 552,241 Six Months Ended June 30, 2022 Eastern Western Mid-Atlantic (1) Resource Solutions Total Revenues Collection $ 110,796 $ 145,997 $ — $ — $ 256,793 Landfill 11,918 32,788 — — 44,706 Transfer 28,905 19,825 — — 48,730 Transportation 3,238 6,682 — — 9,920 Landfill gas-to-energy 522 3,885 — — 4,407 Processing 3,203 1,546 — 61,263 66,012 National Accounts — — — 87,125 87,125 Total revenues $ 158,582 $ 210,723 $ — $ 148,388 $ 517,693 Transferred at a point-in-time $ 236 $ 1,028 $ — $ 33,900 $ 35,164 Transferred over time 158,346 209,695 — 114,488 482,529 Total revenues $ 158,582 $ 210,723 $ — $ 148,388 $ 517,693 (1) Operations under the Mid-Atlantic region did not commence until July 1, 2023, and have had no impact on our operational results for the periods presented in this Quarterly Report on Form 10-Q.

BUSINESS COMBINATIONS (Tables)

BUSINESS COMBINATIONS (Tables)	6 Months Ended
	Jun. 30, 2023
Business Combination and Asset Acquisition [Abstract]
Summary of Purchase Price Paid for Acquisitions	A summary of the purchase price paid and the purchase price allocation for acquisitions follows: Six Months Ended 2023 2022 Purchase Price: Cash used in acquisitions, net of cash acquired $ 544,359 $ 55,053 Holdbacks to sellers and contingent consideration 1,900 3,842 Total consideration $ 546,259 $ 58,895 Allocated as follows: Current assets $ 15,364 $ 7,584 Property, plant and equipment: Land 2,213 2,804 Buildings and improvements 8,666 5,308 Machinery and equipment 90,276 6,712 Operating lease right-of-use assets 11,260 405 Intangible assets: Covenants not-to-compete 10,550 1,415 Customer relationships 93,000 9,725 Other non-current assets — 40 Deferred tax liability (5,160) — Current liabilities (15,195) (3,577) Operating lease liabilities, less current portion (9,887) (282) Fair value of assets acquired and liabilities assumed 201,087 30,134 Excess purchase price allocated to goodwill $ 345,172 $ 28,761
Schedule of Unaudited Pro forma Combined Information	Unaudited pro forma combined information that shows our operational results as though each acquisition completed since the beginning of the prior fiscal year had occurred as of January 1, 2022 is as follows: Three Months Ended Six Months Ended 2023 2022 2023 2022 Revenues $ 335,363 $ 335,299 $ 645,821 $ 626,980 Operating income $ 25,982 $ 35,543 $ 39,734 $ 50,250 Net income $ 7,494 $ 19,985 $ 13,113 $ 26,421 Basic earnings per share attributable to common stockholders: Weighted average common shares outstanding 52,885 51,642 52,331 51,567 Basic earnings per common share $ 0.14 $ 0.39 $ 0.25 $ 0.51 Diluted earnings per share attributable to common stockholders: Weighted average common shares outstanding 52,980 51,781 52,427 51,720 Diluted earnings per common share $ 0.14 $ 0.39 $ 0.25 $ 0.51

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS (Tables)	6 Months Ended
	Jun. 30, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of Goodwill Activity	A summary of the activity and balances related to goodwill by operating segment is as follows: December 31, Acquisitions Measurement Period Adjustments June 30, Eastern $ 52,406 $ — $ — $ 52,406 Western 183,286 11,282 53 194,621 Mid-Atlantic — 333,890 — 333,890 Resource Solutions 38,766 — — 38,766 $ 274,458 $ 345,172 $ 53 $ 619,683
Summary of Intangible Assets by Type	Summaries of intangible assets by type follows: Covenants Customer Relationships Trade Names Total Balance, June 30, 2023 Intangible assets $ 41,863 $ 220,179 $ 8,405 $ 270,447 Less accumulated amortization (25,065) (52,333) (5,901) (83,299) $ 16,798 $ 167,846 $ 2,504 $ 187,148 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 June 30, 2023 Fiscal year ending December 31, 2023 $ 17,546 Fiscal year ending December 31, 2024 $ 33,668 Fiscal year ending December 31, 2025 $ 30,935 Fiscal year ending December 31, 2026 $ 27,532 Fiscal year ending December 31, 2027 $ 24,353 Thereafter $ 53,114

ACCRUED FINAL CAPPING, CLOSUR_2

ACCRUED FINAL CAPPING, CLOSURE AND POST CLOSURE (Tables)	6 Months Ended
	Jun. 30, 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: Six Months Ended 2023 2022 Beginning balance $ 113,678 $ 86,914 Obligations incurred 2,615 2,244 Revision in estimates (1) — 1,443 Accretion expense 4,809 3,799 Obligations settled (2) (2,386) (2,027) Ending balance $ 118,716 $ 92,373 (1) Relates to a change in estimates concerning anticipated capping costs at one of our landfills. (2) May include amounts that are being processed through accounts payable as a part of our disbursements cycle.

DEBT (Tables)

DEBT (Tables)	6 Months Ended
	Jun. 30, 2023
Debt And Derivatives Disclosure [Abstract]
Schedule of Debt	A summary of debt is as follows: June 30, December 31, Senior Secured Credit Facility: Term loan A facility ("Term Loan Facility") due December 2026; bearing interest at Term SOFR plus 1.135% $ 350,000 $ 350,000 Term loan A facility ("2023 Term Loan Facility") due December 2026; bearing interest at Term SOFR plus 2.385% 430,000 — 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 ending in 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 ending in 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 ending in 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 ending in 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 ending in 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 ending in 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 ending in 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 ending in 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 ending in 2029; bearing interest at 2.95% 11,000 11,000 Other: Finance leases 50,228 49,813 Notes payable maturing through March 2025; bearing interest up to 8.1% 339 664 Principal amount of debt 1,027,567 603,477 Less—unamortized debt issuance costs (1) 11,476 9,494 Debt less unamortized debt issuance costs 1,016,091 593,983 Less—current maturities of debt 32,747 8,968 $ 983,344 $ 585,015 (1) A summary of unamortized debt issuance costs by debt instrument follows: June 30, December 31, Revolving Credit Facility, Term Loan Facility and 2023 Term Loan Facility (collectively, the "Credit Facility") $ 7,087 $ 4,716 New York Bonds 2014R-1 832 866 New York Bonds 2014R-2 177 207 New York Bonds 2020 1,016 1,106 FAME Bonds 2005R-3 134 176 FAME Bonds 2015R-1 309 344 FAME Bonds 2015R-2 156 193 Vermont Bonds 2013 351 378 Vermont Bonds 2022A-1 1,079 1,144 New Hampshire Bonds 335 364 $ 11,476 $ 9,494 Term SOFR Loans Base Rate Loans Term Loan Facility 1.125% to 2.125% 0.125% to 1.125% Revolving Credit Facility 1.125% to 2.125% 0.125% to 1.125% 2023 Term Loan Facility 1.625% to 2.625% 0.625% to 1.625%
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 June 30, December 31, Interest rate swaps Other current assets $ 5,147 $ 4,345 Interest rate swaps Other non-current assets 6,763 7,461 $ 11,910 $ 11,806 Interest rate swaps Other long-term liabilities $ 18 $ — Interest rate swaps Accumulated other comprehensive income, net of tax $ 11,892 $ 11,806 Interest rate swaps - tax effect Accumulated other comprehensive income, net of tax (4,284) (4,264) $ 7,608 $ 7,542
Components of Interest Expense	The components of interest expense are as follows: Three Months Ended Six Months Ended 2023 2022 2023 2022 Interest expense on long-term debt and finance leases $ 8,007 $ 5,189 $ 14,437 $ 9,823 Amortization of debt issuance costs (1) 1,004 468 1,505 924 Letter of credit fees 98 116 194 230 Less: capitalized interest (108) (75) (177) (75) Total interest expense $ 9,001 $ 5,698 $ 15,959 $ 10,902

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	6 Months Ended
	Jun. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Summary of Environmental Liability	A summary of the changes to the aggregate environmental remediation liabilities for the six months ended June 30, 2023 and 2022 follows: Six Months Ended 2023 2022 Beginning balance $ 6,335 $ 5,887 Accretion expense 51 54 Obligations settled (1) (320) (72) Ending balance 6,066 5,869 Less: current portion 1,430 280 Long-term portion $ 4,636 $ 5,589 (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)	6 Months Ended
	Jun. 30, 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, June 30, 2023 129 $ 55.60 6.7 $ 4,512 Exercisable, June 30, 2023 49 $ 12.88 2.8 $ 3,793
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 98 $ 80.61 Class A Common Stock Vested (62) $ 62.22 Forfeited (2) $ 71.25 Outstanding, June 30, 2023 203 $ 82.11 1.9 $ 18,339 Unvested, June 30, 2023 362 $ 83.23 1.8 $ 32,798 (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 2,462 Amounts reclassified from accumulated other comprehensive income (2,376) Income tax provision related to items of other comprehensive income (20) Net current-period other comprehensive income, net of tax 66 Balance, June 30, 2023 $ 7,608
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 Six Months Ended 2023 2022 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 $ (1,270) $ 994 $ (2,376) $ 2,122 Interest expense 1,270 (994) 2,376 (2,122) Income before income taxes 348 — 651 (190) Provision for income taxes $ 922 $ (994) $ 1,725 $ (1,932) Net income

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	6 Months Ended
	Jun. 30, 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 Six Months Ended 2023 2022 2023 2022 Numerator: Net income $ 5,490 $ 17,796 $ 9,038 $ 21,986 Denominators: Number of shares outstanding, end of period: Class A common stock 56,974 50,690 56,974 50,690 Class B common stock 988 988 988 988 Unvested restricted stock (1) (2) (1) (2) Effect of weighted average shares outstanding (1) (5,076) (34) (5,630) (109) Basic weighted average common shares outstanding 52,885 51,642 52,331 51,567 Impact of potentially dilutive securities: Dilutive effect of stock options and other stock awards 95 139 96 153 Diluted weighted average common shares outstanding 52,980 51,781 52,427 51,720 Anti-dilutive potentially issuable shares 75 70 84 70 (1) Adjustments in the three and six months ended June 30, 2023 primarily associated with the 6,053 shares of Class A common stock issued as part of the public offering, completed on June 16, 2023, only being outstanding for 14 days in the periods ended June 30, 2023. See Note 9, Stockholders' Equity for disclosure regarding the public offering of Class A common stock.

FAIR VALUE OF FINANCIAL INSTR_2

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	6 Months Ended
	Jun. 30, 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 June 30, 2023 Using: Quoted Prices in Significant Other Significant Assets: Restricted investment securities - landfill closure $ 2,005 $ — $ — Interest rate swaps — 11,910 — $ 2,005 $ 11,910 $ — Liabilities: Contingent consideration - acquisition $ — $ — $ 376 Interest rate swaps — 18 — $ — $ 18 $ 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)	6 Months Ended
	Jun. 30, 2023
Segment Reporting [Abstract]
Summary of Segment Reporting Information by Segment	Three Months Ended June 30, 2023 Segment Outside Inter-company Depreciation and Operating Total Eastern $ 93,323 $ 23,563 $ 12,148 $ 7,519 $ 366,892 Western 124,229 42,342 18,917 18,991 751,324 Mid-Atlantic — — — — 550,758 Resource Solutions 72,093 3,316 3,090 688 203,049 Corporate Entities — — 769 (4,584) 545,269 Eliminations — (69,221) — — — $ 289,645 $ — $ 34,924 $ 22,614 $ 2,417,292 Three Months Ended June 30, 2022 Segment Outside Inter-company Depreciation and Operating Total Eastern $ 87,263 $ 22,147 $ 11,538 $ 6,150 $ 362,942 Western 114,884 39,491 15,939 19,897 697,252 Mid-Atlantic — — — — — Resource Solutions 81,519 317 3,110 6,235 189,820 Corporate Entities — — 563 (563) 120,705 Eliminations — (61,955) — — — $ 283,666 $ — $ 31,150 $ 31,719 $ 1,370,719 Six Months Ended June 30, 2023 Segment Outside Inter-company Depreciation and Operating Total Eastern $ 177,233 $ 42,932 $ 24,051 $ 9,659 $ 366,892 Western 235,262 78,901 36,583 31,417 751,324 Mid-Atlantic — — — — 550,758 Resource Solutions 139,746 6,803 6,166 (1,255) 203,049 Corporate Entities — — 1,559 (6,942) 545,269 Eliminations — (128,636) — — — $ 552,241 $ — $ 68,359 $ 32,879 $ 2,417,292 Six Months Ended June 30, 2022 Segment Outside Inter-company Depreciation and Operating Total Eastern $ 158,582 $ 38,815 $ 22,988 $ 3,920 $ 362,942 Western 210,723 71,983 30,598 29,160 697,252 Mid-Atlantic — — — — — Resource Solutions 148,388 1,095 5,872 9,928 189,820 Corporate Entities — — 1,121 (1,121) 120,705 Eliminations — (111,893) — — — $ 517,693 $ — $ 60,579 $ 41,887 $ 1,370,719
Summary of Revenue Attributable to Services	A summary of our revenues attributable to services provided follows: Three Months Ended Six Months Ended 2023 2022 2023 2022 Collection $ 149,848 $ 137,261 $ 289,825 $ 256,793 Disposal 63,629 60,204 115,096 103,356 Power generation 1,321 1,753 3,245 4,407 Processing 2,754 2,929 4,329 4,749 Solid waste operations 217,552 202,147 412,495 369,305 Processing 25,383 33,867 48,189 61,263 National Accounts 46,710 47,652 91,557 87,125 Resource Solutions operations 72,093 81,519 139,746 148,388 Total revenues $ 289,645 $ 283,666 $ 552,241 $ 517,693

BASIS OF PRESENTATION (Details)

BASIS OF PRESENTATION (Details)	Jun. 30, 2023 state subsidiary
Segment Reporting Information [Line Items]
Number of states in which entity operates | state	7
Number of wholly owned subsidiaries acquired | subsidiary	4

REVENUE RECOGNITION - Disaggreg

REVENUE RECOGNITION - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation of Revenue [Line Items]
Total revenues	$ 289,645	$ 283,666	$ 552,241	$ 517,693
Collection
Disaggregation of Revenue [Line Items]
Total revenues	149,848	137,261	289,825	256,793
Landfill
Disaggregation of Revenue [Line Items]
Total revenues	26,141	25,141	48,901	44,706
Transfer station
Disaggregation of Revenue [Line Items]
Total revenues	32,426	29,274	56,371	48,730
Transportation
Disaggregation of Revenue [Line Items]
Total revenues	5,062	5,789	9,824	9,920
Landfill gas-to-energy
Disaggregation of Revenue [Line Items]
Total revenues	1,321	1,753	3,245	4,407
Processing
Disaggregation of Revenue [Line Items]
Total revenues	28,137	36,796	52,518	66,012
National Accounts
Disaggregation of Revenue [Line Items]
Total revenues	46,710	47,652	91,557	87,125
Transferred at a point-in-time
Disaggregation of Revenue [Line Items]
Total revenues	8,924	19,447	16,211	35,164
Transferred over time
Disaggregation of Revenue [Line Items]
Total revenues	280,721	264,219	536,030	482,529
Eastern
Disaggregation of Revenue [Line Items]
Total revenues	93,323	87,263	177,233	158,582
Eastern | Collection
Disaggregation of Revenue [Line Items]
Total revenues	64,749	59,299	125,858	110,796
Eastern | Landfill
Disaggregation of Revenue [Line Items]
Total revenues	7,220	6,542	13,521	11,918
Eastern | Transfer station
Disaggregation of Revenue [Line Items]
Total revenues	17,698	17,292	31,680	28,905
Eastern | Transportation
Disaggregation of Revenue [Line Items]
Total revenues	1,208	1,765	2,390	3,238
Eastern | Landfill gas-to-energy
Disaggregation of Revenue [Line Items]
Total revenues	173	249	386	522
Eastern | Processing
Disaggregation of Revenue [Line Items]
Total revenues	2,275	2,116	3,398	3,203
Eastern | National Accounts
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Eastern | Transferred at a point-in-time
Disaggregation of Revenue [Line Items]
Total revenues	99	117	218	236
Eastern | Transferred over time
Disaggregation of Revenue [Line Items]
Total revenues	93,224	87,146	177,015	158,346
Western
Disaggregation of Revenue [Line Items]
Total revenues	124,229	114,884	235,262	210,723
Western | Collection
Disaggregation of Revenue [Line Items]
Total revenues	85,099	77,962	163,967	145,997
Western | Landfill
Disaggregation of Revenue [Line Items]
Total revenues	18,921	18,599	35,380	32,788
Western | Transfer station
Disaggregation of Revenue [Line Items]
Total revenues	14,728	11,982	24,691	19,825
Western | Transportation
Disaggregation of Revenue [Line Items]
Total revenues	3,854	4,024	7,434	6,682
Western | Landfill gas-to-energy
Disaggregation of Revenue [Line Items]
Total revenues	1,148	1,504	2,859	3,885
Western | Processing
Disaggregation of Revenue [Line Items]
Total revenues	479	813	931	1,546
Western | National Accounts
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Western | Transferred at a point-in-time
Disaggregation of Revenue [Line Items]
Total revenues	690	517	1,421	1,028
Western | Transferred over time
Disaggregation of Revenue [Line Items]
Total revenues	123,539	114,367	233,841	209,695
Mid-Atlantic
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Mid-Atlantic | Collection
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Mid-Atlantic | Landfill
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Mid-Atlantic | Transfer station
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Mid-Atlantic | Transportation
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Mid-Atlantic | Landfill gas-to-energy
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Mid-Atlantic | Processing
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Mid-Atlantic | National Accounts
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Mid-Atlantic | Transferred at a point-in-time
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Mid-Atlantic | Transferred over time
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Resource Solutions
Disaggregation of Revenue [Line Items]
Total revenues	72,093	81,519	139,746	148,388
Resource Solutions | Collection
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Resource Solutions | Landfill
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Resource Solutions | Transfer station
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Resource Solutions | Transportation
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Resource Solutions | Landfill gas-to-energy
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Resource Solutions | Processing
Disaggregation of Revenue [Line Items]
Total revenues	25,383	33,867	48,189	61,263
Resource Solutions | National Accounts
Disaggregation of Revenue [Line Items]
Total revenues	46,710	47,652	91,557	87,125
Resource Solutions | Transferred at a point-in-time
Disaggregation of Revenue [Line Items]
Total revenues	8,135	18,813	14,572	33,900
Resource Solutions | Transferred over time
Disaggregation of Revenue [Line Items]
Total revenues	$ 63,958	$ 62,706	$ 125,174	$ 114,488

REVENUE RECOGNITION - Narrative

REVENUE RECOGNITION - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Rebates	$ (289,645,000)	$ (283,666,000)	$ (552,241,000)	$ (517,693,000)
Revenue recognized fro performance obligation satisfied in previous period	0	0	0	0
Gross receivables from contracts	119,971,000		119,971,000		$ 102,234,000
Contract liabilities	16,260,000		16,260,000		$ 3,742,000
Rebate for Recycled or Returned Organic Materials
Disaggregation of Revenue [Line Items]
Rebates	$ 6,329,000	$ 5,908,000	$ 12,958,000	$ 9,702,000

BUSINESS COMBINATIONS - Narrati

BUSINESS COMBINATIONS - Narrative (Details) $ in Thousands	1 Months Ended	6 Months Ended
	Jun. 30, 2023 USD ($) property service_line	Jun. 30, 2023 business	Jun. 30, 2022 business
Business Acquisition [Line Items]
Number of businesses acquired | business		2	8
Minimum
Business Acquisition [Line Items]
Useful life of finite lived intangible assets (in years)	2 years	2 years
Maximum
Business Acquisition [Line Items]
Useful life of finite lived intangible assets (in years)	10 years	10 years
Twin Bridges Acquisition
Business Acquisition [Line Items]
Consideration transferred | $	$ 219,000
Twin Bridges Acquisition | Collection
Business Acquisition [Line Items]
Number of service lines acquired | service_line	2
Twin Bridges Acquisition | Transfer station
Business Acquisition [Line Items]
Number of service lines acquired | service_line	1
Twin Bridges Acquisition | Material recovery facility
Business Acquisition [Line Items]
Number of properties acquired | property	1
Twin Bridges Acquisition | Office building
Business Acquisition [Line Items]
Number of properties acquired | property	1

BUSINESS COMBINATIONS - Summary

BUSINESS COMBINATIONS - Summary of Purchase Price Paid for Acquisitions (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Purchase Price:
Cash used in acquisitions, net of cash acquired	$ 547,587	$ 56,250
Allocated as follows:
Excess purchase price allocated to goodwill	619,683		$ 274,458
Waste Collection Acquisitions
Purchase Price:
Cash used in acquisitions, net of cash acquired	544,359	55,053
Holdbacks to sellers and contingent consideration	1,900	3,842
Total consideration	546,259	58,895
Allocated as follows:
Current assets	15,364	7,584
Land	2,213	2,804
Buildings and improvements	8,666	5,308
Machinery and equipment	90,276	6,712
Operating lease right-of-use assets	11,260	405
Other non-current assets	0	40
Deferred tax liability	(5,160)	0
Current liabilities	(15,195)	(3,577)
Operating lease liabilities, less current portion	(9,887)	(282)
Fair value of assets acquired and liabilities assumed	201,087	30,134
Excess purchase price allocated to goodwill	345,172	28,761
Waste Collection Acquisitions | Covenants Not-to-Compete
Allocated as follows:
Intangible assets	10,550	1,415
Waste Collection Acquisitions | Customer Relationships
Allocated as follows:
Intangible assets	$ 93,000	$ 9,725

BUSINESS COMBINATIONS - Schedul

BUSINESS COMBINATIONS - Schedule of Unaudited Pro forma Combined Information (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Business Combination and Asset Acquisition [Abstract]
Revenues	$ 335,363	$ 335,299	$ 645,821	$ 626,980
Operating income	25,982	35,543	39,734	50,250
Net income	$ 7,494	$ 19,985	$ 13,113	$ 26,421
Weighted average common shares outstanding, basic (in shares)	52,885	51,642	52,331	51,567
Basic earnings per common share (in dollars per share)	$ 0.14	$ 0.39	$ 0.25	$ 0.51
Weighted average common shares outstanding, diluted (in shares)	52,980	51,781	52,427	51,720
Diluted earnings per common share (in dollars per share)	$ 0.14	$ 0.39	$ 0.25	$ 0.51

GOODWILL AND INTANGIBLE ASSET_2

GOODWILL AND INTANGIBLE ASSETS - Summary of Goodwill Activity (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2023 USD ($)
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 274,458
Acquisitions	345,172
Measurement Period Adjustments	53
Goodwill, ending balance	619,683
Eastern
Goodwill [Roll Forward]
Goodwill, beginning balance	52,406
Acquisitions	0
Measurement Period Adjustments	0
Goodwill, ending balance	52,406
Western
Goodwill [Roll Forward]
Goodwill, beginning balance	183,286
Acquisitions	11,282
Measurement Period Adjustments	53
Goodwill, ending balance	194,621
Mid-Atlantic
Goodwill [Roll Forward]
Goodwill, beginning balance	0
Acquisitions	333,890
Measurement Period Adjustments	0
Goodwill, ending balance	333,890
Resource Solutions
Goodwill [Roll Forward]
Goodwill, beginning balance	38,766
Acquisitions	0
Measurement Period Adjustments	0
Goodwill, ending balance	$ 38,766

GOODWILL AND INTANGIBLE ASSET_3

GOODWILL AND INTANGIBLE ASSETS - Summary of Intangible Assets by Type (Detail) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Intangible assets	$ 270,447	$ 166,785
Less accumulated amortization	(83,299)	(75,002)
Intangible assets, net	187,148	91,783
Covenants Not-to-Compete
Finite-Lived Intangible Assets [Line Items]
Intangible assets	41,863	31,201
Less accumulated amortization	(25,065)	(24,129)
Intangible assets, net	16,798	7,072
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Intangible assets	220,179	127,179
Less accumulated amortization	(52,333)	(46,162)
Intangible assets, net	167,846	81,017
Trade Names
Finite-Lived Intangible Assets [Line Items]
Intangible assets	8,405	8,405
Less accumulated amortization	(5,901)	(4,711)
Intangible assets, net	$ 2,504	$ 3,694

GOODWILL AND INTANGIBLE ASSET_4

GOODWILL AND INTANGIBLE ASSETS - Narrative (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible amortization expense	$ 4,226	$ 4,262	$ 8,296	$ 8,052

GOODWILL AND INTANGIBLE ASSET_5

GOODWILL AND INTANGIBLE ASSETS - Summary of Intangible Amortization Expense Estimated (Detail) $ in Thousands	Jun. 30, 2023 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Fiscal year ending December 31, 2023	$ 17,546
Fiscal year ending December 31, 2024	33,668
Fiscal year ending December 31, 2025	30,935
Fiscal year ending December 31, 2026	27,532
Fiscal year ending December 31, 2027	24,353
Thereafter	$ 53,114

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	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	$ 113,678	$ 86,914
Obligations incurred	2,615	2,244
Revision in estimates	0	1,443
Accretion expense	4,809	3,799
Obligations settled	(2,386)	(2,027)
Ending balance	$ 118,716	$ 92,373

DEBT - Summary of Debt (Details

DEBT - Summary of Debt (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 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%	$ 50,228	$ 49,813
Principal amount of debt	1,027,567	603,477
Less - unamortized debt issuance costs	11,476	9,494
Debt less unamortized debt issuance costs	1,016,091	593,983
Less—current maturities of debt	32,747	8,968
Debt, less current portion	$ 983,344	$ 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 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 SOFR plus 1.135% | SOFR
Debt Instrument [Line Items]
Variable rate margin	1.135%
Secured Debt | Term loan A facility ("2023 Term Loan Facility") due December 2026; bearing interest at Term SOFR plus 2.385%
Debt Instrument [Line Items]
Principal amount of debt	$ 430,000	0
Secured Debt | Term loan A facility ("2023 Term Loan Facility") due December 2026; bearing interest at Term SOFR plus 2.385% | SOFR
Debt Instrument [Line Items]
Variable rate margin	2.385%
Secured Debt | Revolving credit facility ("Revolving Credit Facility") due December 2026; bearing interest at Term SOFR plus 1.135% | SOFR
Debt Instrument [Line Items]
Variable rate margin	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, Term Loan Facility and 2023 Term Loan Facility (collectively, the "Credit Facility")
Debt Instrument [Line Items]
Less - unamortized debt issuance costs	$ 7,087	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 ending in 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	$ 832	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 ending in 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	$ 177	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 ending in 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	$ 1,016	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 ending in 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	$ 134	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 ending in 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	$ 309	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 ending in 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	$ 156	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 ending in 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	$ 351	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 ending in 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	$ 1,079	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 ending in 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	$ 335	364
Notes payable maturing through March 2025; bearing interest up to 8.1%
Debt Instrument [Line Items]
Stated interest rate	8.10%
Principal amount of debt	$ 339	$ 664

DEBT - Financing Activities (De

DEBT - Financing Activities (Details) - USD ($) $ in Thousands	1 Months Ended	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2023	May 31, 2023	Apr. 30, 2023
Line of Credit Facility [Line Items]
Deferred financing costs	$ 4,580	$ 4,580
Credit Facility | SOFR
Line of Credit Facility [Line Items]
Variable rate adjustment		0.10%
Secured Debt
Line of Credit Facility [Line Items]
Bridge loan				$ 375,000
Secured Debt | Term loan A facility ("2023 Term Loan Facility") due December 2026; bearing interest at Term SOFR plus 2.385%
Line of Credit Facility [Line Items]
Aggregate principal amount issued			$ 430,000
Proceeds from issuance of debt	430,000
Unsecured Debt
Line of Credit Facility [Line Items]
Bridge loan	$ 200,000	$ 200,000

DEBT - Credit Facility Narrativ

DEBT - Credit Facility Narrative (Details) - USD ($)	6 Months Ended
	Jun. 30, 2023	May 31, 2023	Dec. 31, 2022
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]
Commitment fee adjustment	0.01%
Floor interest rate	0%
Interest rate, annual increase upon payment default	2%
Interest rate, annual increase upon other event of default	2%
Credit Facility | Minimum
Line of Credit Facility [Line Items]
Commitment fee, margin percent	0.20%
Credit Facility | Maximum
Line of Credit Facility [Line Items]
Commitment fee, margin percent	0.40%
Credit Facility | SOFR
Line of Credit Facility [Line Items]
Variable rate adjustment	0.10%
Credit Facility | Base Rate
Line of Credit Facility [Line Items]
Variable rate adjustment	0.04%
Secured Debt | Term loan A facility ("Term Loan Facility") due December 2026; bearing interest at Term SOFR plus 1.135%
Line of Credit Facility [Line Items]
Aggregate principal amount issued	$ 350,000,000
Principal amount of debt	350,000,000		$ 350,000,000
Secured Debt | Term loan A facility ("2023 Term Loan Facility") due December 2026; bearing interest at Term SOFR plus 2.385%
Line of Credit Facility [Line Items]
Aggregate principal amount issued		$ 430,000,000
Principal amount of debt	430,000,000		0
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
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
Line of Credit | Credit Facility | Letter of Credit
Line of Credit Facility [Line Items]
Fronting fee	0.25%
Line of Credit | Revolving credit facility ("Revolving Credit Facility") due December 2026; bearing interest at Term SOFR plus 1.135%
Line of Credit Facility [Line Items]
Principal amount of debt	$ 0		$ 6,000,000

DEBT - Variable Rate Margins (D

DEBT - Variable Rate Margins (Details)	6 Months Ended
	Jun. 30, 2023
Term loan A facility ("Term Loan Facility") due December 2026; bearing interest at Term SOFR plus 1.135% | SOFR | Secured Debt
Debt Instrument [Line Items]
Variable rate margin	1.135%
Term loan A facility ("Term Loan Facility") due December 2026; bearing interest at Term SOFR plus 1.135% | SOFR | Minimum | Secured Debt
Debt Instrument [Line Items]
Variable rate margin	1.125%
Term loan A facility ("Term Loan Facility") due December 2026; bearing interest at Term SOFR plus 1.135% | SOFR | Maximum | Secured Debt
Debt Instrument [Line Items]
Variable rate margin	2.125%
Term loan A facility ("Term Loan Facility") due December 2026; bearing interest at Term SOFR plus 1.135% | Base Rate | Minimum | Secured Debt
Debt Instrument [Line Items]
Variable rate margin	0.125%
Term loan A facility ("Term Loan Facility") due December 2026; bearing interest at Term SOFR plus 1.135% | Base Rate | Maximum | Secured Debt
Debt Instrument [Line Items]
Variable rate margin	1.125%
Revolving credit facility ("Revolving Credit Facility") due December 2026; bearing interest at Term SOFR plus 1.135% | SOFR | Secured Debt
Debt Instrument [Line Items]
Variable rate margin	1.135%
Revolving credit facility ("Revolving Credit Facility") due December 2026; bearing interest at Term SOFR plus 1.135% | SOFR | Minimum | Line of Credit
Debt Instrument [Line Items]
Variable rate margin	1.125%
Revolving credit facility ("Revolving Credit Facility") due December 2026; bearing interest at Term SOFR plus 1.135% | SOFR | Maximum | Line of Credit
Debt Instrument [Line Items]
Variable rate margin	2.125%
Revolving credit facility ("Revolving Credit Facility") due December 2026; bearing interest at Term SOFR plus 1.135% | Base Rate | Minimum | Line of Credit
Debt Instrument [Line Items]
Variable rate margin	0.125%
Revolving credit facility ("Revolving Credit Facility") due December 2026; bearing interest at Term SOFR plus 1.135% | Base Rate | Maximum | Line of Credit
Debt Instrument [Line Items]
Variable rate margin	1.125%
Term loan A facility ("2023 Term Loan Facility") due December 2026; bearing interest at Term SOFR plus 2.385% | SOFR | Secured Debt
Debt Instrument [Line Items]
Variable rate margin	2.385%
Term loan A facility ("2023 Term Loan Facility") due December 2026; bearing interest at Term SOFR plus 2.385% | SOFR | Minimum | Secured Debt
Debt Instrument [Line Items]
Variable rate margin	1.625%
Term loan A facility ("2023 Term Loan Facility") due December 2026; bearing interest at Term SOFR plus 2.385% | SOFR | Maximum | Secured Debt
Debt Instrument [Line Items]
Variable rate margin	2.625%
Term loan A facility ("2023 Term Loan Facility") due December 2026; bearing interest at Term SOFR plus 2.385% | Base Rate | Minimum | Secured Debt
Debt Instrument [Line Items]
Variable rate margin	0.625%
Term loan A facility ("2023 Term Loan Facility") due December 2026; bearing interest at Term SOFR plus 2.385% | Base Rate | Maximum | Secured Debt
Debt Instrument [Line Items]
Variable rate margin	1.625%

DEBT - Components of Interest E

DEBT - Components of Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Debt Instrument [Line Items]
Interest expense on long-term debt and finance leases	$ 8,007	$ 5,189	$ 14,437	$ 9,823
Amortization of debt issuance costs	1,004	468	1,505	924
Letter of credit fees	98	116	194	230
Less: capitalized interest	(108)	(75)	(177)	(75)
Total interest expense	9,001	$ 5,698	15,959	$ 10,902
GFL Acquisition
Debt Instrument [Line Items]
Amortization of debt issuance costs	395		395
Twin Bridges Acquisition
Debt Instrument [Line Items]
Amortization of debt issuance costs	$ 101		$ 101

DEBT - Loss from Termination of

DEBT - Loss from Termination of Bridge Financing (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Debt Instrument [Line Items]
Loss from termination of bridge financing	$ 8,198	$ 0	$ 8,198	$ 0
GFL Acquisition
Debt Instrument [Line Items]
Loss from termination of bridge financing	3,718		3,718
Twin Bridges Acquisition
Debt Instrument [Line Items]
Loss from termination of bridge financing	$ 4,480		$ 4,480

DEBT - Cash Flow Hedges Narrati

DEBT - Cash Flow Hedges Narrative (Details) - USD ($) $ in Thousands	Jul. 28, 2023	Jun. 30, 2023	Dec. 31, 2022
Term loan A facility ("2023 Term Loan Facility") due December 2026; bearing interest at Term SOFR plus 2.385% | Secured Debt
Debt Instrument [Line Items]
Principal amount of debt		$ 430,000	$ 0
Cash Flow Hedging | Interest Rate Derivative
Debt Instrument [Line Items]
Notional amount		$ 165,000	190,000
Floor interest rate (as a percent)		0%
Weighted average percentage rate paid (as a percent)		2.08%
Cash Flow Hedging | Interest Rate Derivative | Subsequent Event
Debt Instrument [Line Items]
Notional amount	$ 250,000
Floor interest rate (as a percent)	0%
Weighted average percentage rate paid (as a percent)	4.285%
Cash Flow Hedging | Forward Starting Interest Rate Derivative
Debt Instrument [Line Items]
Notional amount			$ 20,000

DEBT - Summary of Cash Flow Hed

DEBT - Summary of Cash Flow Hedges (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Derivatives, Fair Value [Line Items]
Accumulated other comprehensive income, net of tax	$ 7,608	$ 7,542
Designated as Hedging Instrument | Interest rate swaps
Derivatives, Fair Value [Line Items]
Cash flow hedge derivatives, gross asset	11,910	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	11,892	11,806
Accumulated other comprehensive income, tax	(4,284)	(4,264)
Accumulated other comprehensive income, net of tax	7,608	7,542
Other current assets | Designated as Hedging Instrument | Interest rate swaps
Derivatives, Fair Value [Line Items]
Cash flow hedge derivatives, gross asset	5,147	4,345
Other non-current assets | Designated as Hedging Instrument | Interest rate swaps
Derivatives, Fair Value [Line Items]
Cash flow hedge derivatives, gross asset	6,763	7,461
Other long-term liabilities | Designated as Hedging Instrument | Interest rate swaps
Derivatives, Fair Value [Line Items]
Cash flow hedge derivatives, gross liability	$ 18	$ 0

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Narrative (Detail) $ in Thousands	Jun. 30, 2023 USD ($)
Loss Contingencies [Line Items]
Loss contingency accrual	$ 6,208
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	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	$ 6,335	$ 5,887
Obligations settled	(320)	(72)
Ending balance	6,066	5,869
Less: current portion	1,430	280
Long-term portion	4,636	5,589
Other environmental remediation sites
Accrual for Environmental Loss Contingencies [Roll Forward]
Accretion expense	$ 51	$ 54

STOCKHOLDERS' EQUITY - Narrativ

STOCKHOLDERS' EQUITY - Narrative (Detail) - USD ($)		3 Months Ended		6 Months Ended
	Jun. 16, 2023	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation, weighted average period				4 years
Fair value of stock awards vested		$ 1,094,000		$ 5,056,000
Stock Options
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense		125,000	$ 17,000	248,000	$ 33,000
Unrecognized stock-based compensation expense, stock options		1,850,000		1,850,000
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		2,132,000	828,000	3,894,000	2,979,000
Restricted Stock
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense		17,000		$ 17,000
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		5,905,000		$ 5,905,000
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		6,791,000		$ 6,791,000
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				10 months 24 days
Weighted average | Restricted Stock Unit
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation, weighted average period				2 years
Weighted average | Performance Stock Unit
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation, weighted average period				1 year 10 months 24 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		$ 109,000	$ 199,000	$ 93,000	$ 166,000
Class A Common Stock
Limited Partners' Capital Account [Line Items]
Number of shares issued	6,053,000	6,053,000		6,053,000
Public offering price (in dollars per share)	$ 85.50
Net proceeds	$ 496,403,000
Class A Common Stock | 2016 Plan
Limited Partners' Capital Account [Line Items]
Common stock, authorized shares (in shares)		2,250,000		2,250,000
Number of shares available for future grant (in shares)		640,000		640,000
Class A Common Stock | 2006 Incentive Plan
Limited Partners' Capital Account [Line Items]
Common stock, additional authorized shares (in shares)				2,723,000
Class A Common Stock | Amended and Restated 1997 Employee Stock Purchase Plan
Limited Partners' Capital Account [Line Items]
Common stock, additional authorized shares (in shares)		400,000
Number of shares available for future grant (in shares)		444,000		444,000

STOCKHOLDERS' EQUITY - Summary

STOCKHOLDERS' EQUITY - Summary of Stock Option Activity (Detail) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended
	Jun. 30, 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 8 months 12 days
Exercisable contractual term	2 years 9 months 18 days
Outstanding aggregate intrinsic value | $	$ 4,512
Exercisable aggregate intrinsic value | $	$ 3,793

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	6 Months Ended
	Jun. 30, 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)	98
Forfeited (in shares)	(2)
Outstanding, end of period (in shares)	203
Weighted Average Grant Date Fair Value
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 75.52
Granted (in dollars per share) | $ / shares	80.61
Forfeited (in dollars per share) | $ / shares	71.25
Outstanding at end of period (in dollars per share) | $ / shares	$ 82.11
Weighted Average Remaining Contractual Term (years) and Aggregate Intrinsic Value
Contractual term (in years)	1 year 10 months 24 days
Aggregate intrinsic value | $	$ 18,339
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)	(62)
Weighted Average Grant Date Fair Value
Class A Common Stock Vested (in dollars per share) | $ / shares	$ 62.22
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)	362
Weighted Average Grant Date Fair Value
Outstanding at end of period (in dollars per share) | $ / shares	$ 83.23
Weighted Average Remaining Contractual Term (years) and Aggregate Intrinsic Value
Contractual term (in years)	1 year 9 months 18 days
Aggregate intrinsic value | $	$ 32,798

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				6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 501,655	$ 497,900	$ 435,050	$ 422,457	$ 497,900	$ 422,457
Other comprehensive income, net of tax	1,835	(1,769)	2,980	6,143	66	9,123
Ending balance	1,008,383	501,655	$ 457,566	$ 435,050	1,008,383	$ 457,566
Accumulated gain (loss), cash flow hedge
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance		$ 7,542			7,542
Other comprehensive income before reclassifications					2,462
Amounts reclassified from accumulated other comprehensive income					(2,376)
Income tax provision related to items of other comprehensive income					(20)
Other comprehensive income, net of tax					66
Ending balance	$ 7,608				$ 7,608

STOCKHOLDERS' EQUITY - Summar_4

STOCKHOLDERS' EQUITY - Summary of Reclassifications Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ 9,001		$ 5,698		$ 15,959	$ 10,902
Income before income taxes	7,478		26,375		11,817	31,523
Provision for income taxes	1,988		8,579		2,779	9,537
Net income	5,490	$ 3,548	17,796	$ 4,190	9,038	21,986
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	1,270		(994)		2,376	(2,122)
Provision for income taxes	348		0		651	(190)
Net income	922		(994)		1,725	(1,932)
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	$ (1,270)		$ 994		$ (2,376)	$ 2,122

EARNINGS PER SHARE (Details)

EARNINGS PER SHARE (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Jun. 16, 2023	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Numerator:
Net income		$ 5,490	$ 17,796	$ 9,038	$ 21,986
Denominators:
Unvested restricted stock (in shares)		(1,000)	(2,000)	(1,000)	(2,000)
Effect of weighted average shares outstanding (in shares)		(5,076,000)	(34,000)	(5,630,000)	(109,000)
Weighted average common shares outstanding, basic (in shares)		52,885,000	51,642,000	52,331,000	51,567,000
Impact of potentially dilutive securities:
Dilutive effect of stock options and other stock awards (in shares)		95,000	139,000	96,000	153,000
Weighted average common shares outstanding, diluted		52,980,000	51,781,000	52,427,000	51,720,000
Anti-dilutive potentially issuable shares (in shares)		75,000	70,000	84,000	70,000
Class A Common Stock
Denominators:
Common stock, shares outstanding (in shares)		56,974,000	50,690,000	56,974,000	50,690,000	50,704,000
Impact of potentially dilutive securities:
Number of shares issued	6,053,000	6,053,000		6,053,000
Period shares outstanding		14 days		14 days
Class B Common Stock
Denominators:
Common stock, shares outstanding (in shares)		988,000	988,000	988,000	988,000	988,000

OTHER ITEMS AND CHARGES (Detail

OTHER ITEMS AND CHARGES (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Unusual or Infrequent Items, or Both [Abstract]
Expense from acquisition activities	$ 3,677	$ 1,019	$ 6,540	$ 3,062
Legal settlement	$ 6,150	$ 0	$ 6,150	$ 0

FAIR VALUE OF FINANCIAL INSTR_3

FAIR VALUE OF FINANCIAL INSTRUMENTS - Recurring Fair Value Measurements (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Assets:
Restricted investment securities - landfill closure	$ 2,005	$ 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	2,005	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	2,005	1,900
Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Interest rate swaps	11,910	11,806
Total assets	11,910	11,806
Liabilities:
Contingent consideration - acquisition	0	0
Interest rate swaps	18
Total	18
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 ($)	Jun. 30, 2023	Dec. 31, 2022
Term loan A facility ("Term Loan Facility") due December 2026; bearing interest at Term SOFR plus 1.135% | Secured Debt
Debt Instrument [Line Items]
Principal amount of debt	$ 350,000,000	$ 350,000,000
Term loan A facility ("2023 Term Loan Facility") due December 2026; bearing interest at Term SOFR plus 2.385% | Secured Debt
Debt Instrument [Line Items]
Principal amount of debt	430,000,000	$ 0
Fair Value | Fixed Rate Bonds
Debt Instrument [Line Items]
Fixed rate debt	190,876,000
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		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Segment Reporting Information [Line Items]
Revenues	$ 289,645	$ 283,666	$ 552,241	$ 517,693
Depreciation and amortization	34,924	31,150	68,359	60,579
Operating income (loss)	22,614	31,719	32,879	41,887
Total assets	2,417,292	1,370,719	2,417,292	1,370,719	$ 1,449,215
Operating | Eastern
Segment Reporting Information [Line Items]
Revenues	93,323	87,263	177,233	158,582
Depreciation and amortization	12,148	11,538	24,051	22,988
Operating income (loss)	7,519	6,150	9,659	3,920
Total assets	366,892	362,942	366,892	362,942
Operating | Western
Segment Reporting Information [Line Items]
Revenues	124,229	114,884	235,262	210,723
Depreciation and amortization	18,917	15,939	36,583	30,598
Operating income (loss)	18,991	19,897	31,417	29,160
Total assets	751,324	697,252	751,324	697,252
Operating | Mid-Atlantic
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Depreciation and amortization	0	0	0	0
Operating income (loss)	0	0	0	0
Total assets	550,758	0	550,758	0
Operating | Resource Solutions
Segment Reporting Information [Line Items]
Revenues	72,093	81,519	139,746	148,388
Depreciation and amortization	3,090	3,110	6,166	5,872
Operating income (loss)	688	6,235	(1,255)	9,928
Total assets	203,049	189,820	203,049	189,820
Corporate Entities
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Depreciation and amortization	769	563	1,559	1,121
Operating income (loss)	(4,584)	(563)	(6,942)	(1,121)
Total assets	545,269	120,705	545,269	120,705
Inter-company revenues
Segment Reporting Information [Line Items]
Revenues	(69,221)	(61,955)	(128,636)	(111,893)
Inter-company revenues | Eastern
Segment Reporting Information [Line Items]
Revenues	(23,563)	(22,147)	(42,932)	(38,815)
Inter-company revenues | Western
Segment Reporting Information [Line Items]
Revenues	(42,342)	(39,491)	(78,901)	(71,983)
Inter-company revenues | Mid-Atlantic
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Inter-company revenues | Resource Solutions
Segment Reporting Information [Line Items]
Revenues	$ (3,316)	$ (317)	$ (6,803)	$ (1,095)

SEGMENT REPORTING - Summary o_2

SEGMENT REPORTING - Summary of Revenues Attributable to Services Provided by Company (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Revenue from External Customer [Line Items]
Revenues	$ 289,645	$ 283,666	$ 552,241	$ 517,693
Solid waste operations
Revenue from External Customer [Line Items]
Revenues	217,552	202,147	412,495	369,305
Collection
Revenue from External Customer [Line Items]
Revenues	149,848	137,261	289,825	256,793
Disposal
Revenue from External Customer [Line Items]
Revenues	63,629	60,204	115,096	103,356
Power generation
Revenue from External Customer [Line Items]
Revenues	1,321	1,753	3,245	4,407
Processing
Revenue from External Customer [Line Items]
Revenues	2,754	2,929	4,329	4,749
Resource Solutions operations
Revenue from External Customer [Line Items]
Revenues	72,093	81,519	139,746	148,388
Processing
Revenue from External Customer [Line Items]
Revenues	25,383	33,867	48,189	61,263
National Accounts
Revenue from External Customer [Line Items]
Revenues	$ 46,710	$ 47,652	$ 91,557	$ 87,125