Casella Waste Systems (CWST) 10-Q 29 Jul 22 2022 Q2 Quarterly report Financial data

COVER

COVER - shares	6 Months Ended
	Jun. 30, 2022	Jul. 15, 2022
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2022
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	2022
Document Fiscal Period Focus	Q2
Amendment Flag	false
Class A Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		50,689,841
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, 2022	Dec. 31, 2021
CURRENT ASSETS:
Cash and cash equivalents	$ 39,309	$ 33,809
Accounts receivable, net of allowance for credit losses of $3,879 and $3,276, respectively	108,313	86,979
Prepaid expenses	17,517	12,766
Inventory	13,071	9,729
Other current assets	2,946	3,196
Total current assets	181,156	146,479
Property, plant and equipment, net of accumulated depreciation and amortization of $1,016,382 and $973,094, respectively	668,381	644,604
Operating lease right-of-use assets	93,253	93,799
Goodwill	262,508	232,860
Intangible assets, net	96,762	93,723
Restricted cash and assets	2,805	2,122
Cost method investments	11,264	11,264
Deferred income taxes	34,060	43,957
Other non-current assets	20,530	14,772
Total assets	1,370,719	1,283,580
CURRENT LIABILITIES:
Current maturities of debt	7,636	9,901
Current operating lease liabilities	6,425	7,307
Accounts payable	73,270	63,086
Accrued payroll and related expenses	16,392	22,210
Accrued interest	2,372	2,042
Contract liabilities	3,733	3,404
Current accrued capping, closure and post-closure costs	5,815	7,915
Other accrued liabilities	47,371	36,328
Total current liabilities	163,014	152,193
Debt, less current portion	575,556	542,503
Operating lease liabilities, less current portion	59,027	56,375
Accrued capping, closure and post-closure costs, less current portion	86,558	78,999
Deferred income taxes	902	868
Other long-term liabilities	28,096	30,185
COMMITMENTS AND CONTINGENCIES
STOCKHOLDERS' EQUITY:
Additional paid-in capital	656,042	652,045
Accumulated deficit	(203,013)	(224,999)
Accumulated other comprehensive income (loss), net of tax	4,020	(5,103)
Total stockholders' equity	457,566	422,457
Total liabilities and stockholders' equity	1,370,719	1,283,580
Class A Common Stock
STOCKHOLDERS' EQUITY:
Common stock	507	504
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, 2022 USD ($) vote $ / shares shares	Dec. 31, 2021 USD ($) vote $ / shares shares
Accounts receivable - trade, allowance for credit losses | $	$ 3,879	$ 3,276
Accumulated depreciation and amortization | $	$ 1,016,382	$ 973,094
Class A Common Stock
Common stock, par value (in dollars per share) | $ / shares	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	50,690,000	50,423,000
Common stock, shares outstanding (in shares)	50,690,000	50,423,000
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, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Income Statement [Abstract]
Revenues	$ 283,666	$ 215,875	$ 517,693	$ 405,406
Operating expenses:
Cost of operations	186,038	138,553	348,493	265,691
General and administration	33,562	29,212	63,354	56,343
Depreciation and amortization	31,150	24,337	60,579	47,019
Expense from acquisition activities	1,019	1,632	3,062	2,046
Southbridge Landfill closure charge	178	195	318	352
Total operating expenses	251,947	193,929	475,806	371,451
Operating income	31,719	21,946	41,887	33,955
Other expense (income):
Interest income	(42)	(66)	(81)	(130)
Interest expense	5,698	5,296	10,902	10,764
Other income	(312)	(510)	(457)	(648)
Other expense, net	5,344	4,720	10,364	9,986
Income before income taxes	26,375	17,226	31,523	23,969
Provision for income taxes	8,579	5,443	9,537	7,875
Net income	$ 17,796	$ 11,783	$ 21,986	$ 16,094
Basic earnings per share attributable to common stockholders:
Weighted average common shares outstanding, basic (in shares)	51,642	51,366	51,567	51,273
Basic earnings per common share (in dollars per share)	$ 0.34	$ 0.23	$ 0.43	$ 0.31
Diluted earnings per share attributable to common stockholders:
Weighted average common shares outstanding, diluted (in shares)	51,781	51,546	51,720	51,466
Diluted earnings per common share (in dollars per share)	$ 0.34	$ 0.23	$ 0.43	$ 0.31

UNAUDITED CONSOLIDATED STATEM_2

UNAUDITED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 17,796	$ 11,783	$ 21,986	$ 16,094
Hedging activity:
Interest rate swap settlements	(932)	(1,186)	(2,095)	(2,346)
Interest rate swap amounts reclassified into interest expense	994	1,202	2,122	2,347
Unrealized gain (loss) resulting from changes in fair value of derivative instruments	3,488	(336)	11,869	4,651
Other comprehensive income (loss), before tax	3,550	(320)	11,896	4,652
Income tax provision (benefit) related to items of other comprehensive income	570	(85)	2,773	1,057
Other comprehensive income (loss), net of tax	2,980	(235)	9,123	3,595
Comprehensive income	$ 20,776	$ 11,548	$ 31,109	$ 19,689

UNAUDITED CONSOLIDATED STATEM_3

UNAUDITED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Additional Paid-In Capital	Accumulated Deficit	Accumulated other comprehensive income (loss), 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, 2020	$ 362,142	$ 639,247	$ (266,099)	$ (11,517)		$ 501		$ 10
Beginning balance (in shares) at Dec. 31, 2020						50,101,000		988,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances of Class A common stock	112	109				$ 3
Issuance of Class A common stock (in shares)						273,000
Stock-based compensation	2,941	2,941
Net income (loss)	4,311		4,311
Hedging activity	3,830			3,830
Ending balance at Mar. 31, 2021	373,336	642,297	(261,788)	(7,687)		$ 504		$ 10
Ending balance (in shares) at Mar. 31, 2021						50,374,000		988,000
Beginning balance at Dec. 31, 2020	362,142	639,247	(266,099)	(11,517)		$ 501		$ 10
Beginning balance (in shares) at Dec. 31, 2020						50,101,000		988,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	16,094
Hedging activity	3,595
Ending balance at Jun. 30, 2021	388,492	645,905	(250,005)	(7,922)		$ 504		$ 10
Ending balance (in shares) at Jun. 30, 2021					50,398,000	50,398,000	988,000	988,000
Beginning balance at Mar. 31, 2021	373,336	642,297	(261,788)	(7,687)		$ 504		$ 10
Beginning balance (in shares) at Mar. 31, 2021						50,374,000		988,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances of Class A common stock	492	492
Issuance of Class A common stock (in shares)						24,000
Stock-based compensation	3,116	3,116
Net income (loss)	11,783		11,783
Hedging activity	(235)			(235)
Ending balance at Jun. 30, 2021	388,492	645,905	(250,005)	(7,922)		$ 504		$ 10
Ending balance (in shares) at Jun. 30, 2021					50,398,000	50,398,000	988,000	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	50,423,000	988,000	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	50,423,000	988,000	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

UNAUDITED CONSOLIDATED STATEM_4

UNAUDITED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash Flows from Operating Activities:
Net income	$ 21,986	$ 16,094
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	60,579	47,019
Interest accretion on landfill and environmental remediation liabilities	4,015	3,962
Amortization of debt issuance costs	924	1,144
Stock-based compensation	3,178	6,057
Operating lease right-of-use assets expense	6,824	6,407
Gain on sale of property and equipment	(269)	(92)
Non-cash expense from acquisition activities	645	1,022
Deferred income taxes	7,156	7,041
Changes in assets and liabilities, net of effects of acquisitions and divestitures:
Accounts receivable	(14,667)	(4,712)
Landfill operating lease contract expenditures	(1,308)	(1,478)
Accounts payable	10,142	10,866
Prepaid expenses, inventories and other assets	(6,099)	(7,192)
Accrued expenses, contract liabilities and other liabilities	(855)	(7,125)
Net cash provided by operating activities	92,251	79,013
Cash Flows from Investing Activities:
Acquisitions, net of cash acquired	(56,250)	(5,481)
Additions to property, plant and equipment	(54,868)	(56,069)
Proceeds from sale of property and equipment	507	403
Net cash used in investing activities	(110,611)	(61,147)
Cash Flows from Financing Activities:
Proceeds from debt borrowings	82,200	500
Principal payments on debt	(55,297)	(5,643)
Payments of debt issuance costs	(1,229)	0
Payments of contingent consideration	(1,000)	0
Proceeds from the exercise of share based awards	192	112
Net cash provided by (used in) financing activities	24,866	(5,031)
Net increase in cash and cash equivalents	6,506	12,835
Cash, cash equivalents and restricted cash, beginning of period	33,809	154,342
Cash, cash equivalents and restricted cash, end of period	40,315	167,177
Supplemental Disclosure of Cash Flow Information:
Cash interest payments	9,648	9,701
Cash income tax payments	2,092	411
Non-current assets obtained through long-term financing obligations	4,190	5,894
Right-of-use assets obtained in exchange for operating lease obligations	$ 5,194	$ 1,251

BASIS OF PRESENTATION

BASIS OF PRESENTATION	6 Months Ended
	Jun. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
BASIS OF PRESENTATION	BASIS OF PRESENTATION Casella Waste Systems, Inc. (“Parent”), and its subsidiaries (collectively, “we”, “us” or “our”), is a regional, vertically integrated solid waste services company. We provide resource management expertise and services to residential, commercial, municipal, institutional and industrial customers, primarily in the areas of solid waste collection and disposal, transfer, recycling and organics services. We provide integrated solid waste services in seven states: Vermont, New Hampshire, New York, Massachusetts, Connecticut, Maine and Pennsylvania, with our headquarters located in Rutland, Vermont. We manage our solid waste operations on a geographic basis through two regional operating segments, the Eastern and Western regions, each of which provides a full range of solid waste services. We manage our resource-renewal operations through the Resource Solutions operating segment, which leverages our core competencies in materials processing, industrial recycling, organics and resource management service offerings to deliver a comprehensive solution for our larger commercial, municipal, institutional and industrial customers that have more diverse waste and recycling needs. Legal, tax, information technology, human resources, certain finance and accounting and other administrative functions are included in our Corporate Entities segment. The accompanying unaudited consolidated financial statements, which include the accounts of the Parent and our wholly-owned subsidiaries, have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). All significant intercompany accounts and transactions are eliminated in consolidation. Investments in entities in which we do not have a controlling financial interest are accounted for under either the equity method or the cost method of accounting, as appropriate. Our significant accounting policies are more fully discussed in Item 8, " Financial Statements and Supplementary Data " of our Annual Report on Form 10-K for the fiscal year ended December 31, 2021 ("fiscal year 2021"), which was filed with the SEC on February 18, 2022. 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, 2022 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 Annual Report on Form 10-K for fiscal year 2021. Subsequent Events We have evaluated subsequent events or transactions that have occurred after the consolidated balance sheet date of June 30, 2022 through the date of filing of the consolidated financial statements with the SEC on this Quarterly Report on Form 10-Q. We have determined that there are no subsequent events that require disclosure in this Quarterly Report on Form 10-Q.

ACCOUNTING CHANGES

ACCOUNTING CHANGES	6 Months Ended
	Jun. 30, 2022
Accounting Changes and Error Corrections [Abstract]
ACCOUNTING CHANGES	ACCOUNTING CHANGES A table providing a brief description of recent Accounting Standards Updates ("ASUs") to the Accounting Standards Codification ("ASC") issued by the Financial Accounting Standards Board (“FASB”) that are pending adoption and deemed to have a possible material impact on our consolidated financial statements based on current account balances and activity follows: Standard Description Effect on the Financial Statements or Other Accounting standards issued pending adoption ASU No. 2020-04: Reference Rate Reform (Topic 848), as amended through January 2021 Provides temporary optional guidance to ease the potential burden in applying GAAP to contract modifications and hedging relationships that reference London Inter-Bank Offered Rate ("LIBOR") or another reference rate expected to be discontinued, subject to meeting certain criteria. We currently have interest rate derivative agreements with hedging relationships that reference LIBOR. 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. We are currently assessing the provisions of this guidance, and reviewing and updating our existing contracts, as applicable, for transition or fallback language that specifies how a replacement rate for LIBOR will be identified. We are also no longer using LIBOR as a reference rate for any new contracts. We do not expect that the adoption of this guidance will have a material impact on our consolidated financial statements and related disclosures. This guidance will be in effect from March 12, 2020 through December 31, 2022. See Note 7, Debt for further disclosure over our interest rate derivative agreements and debt instruments that reference LIBOR. ASU No. 2021-08: Accounting for Contract Assets and Contract Liabilities from Contracts with Customers (Topic 805) Requires entities to apply ASC 606 to recognize and measure contract assets and contract liabilities in a business combination. This guidance improves comparability after the business combination by providing consistent recognition and measurement guidance for revenue contracts with customers acquired in a business combination and revenue contracts with customers not acquired in a business combination. We have made in the past, and we may make in the future, acquisitions to densify existing operations, expand service areas, and grow services for our customers, and these acquisitions may include contract assets or contract liabilities. We do not expect that the adoption of this guidance will have a material impact on our consolidated financial statements and related disclosures. This guidance is effective January 1, 2023 with early adoption permitted.

REVENUE RECOGNITION

REVENUE RECOGNITION	6 Months Ended
	Jun. 30, 2022
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 services are derived from processing and non-processing services. 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, 2022 and 2021: Three Months Ended June 30, 2022 Eastern Western Resource Solutions Total Revenues Collection $ 59,299 $ 77,962 $ — $ 137,261 Landfill 6,542 18,599 — 25,141 Transfer 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 Non-processing — — 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 Three Months Ended June 30, 2021 Eastern Western Resource Solutions Total Revenues Collection $ 39,364 $ 67,963 $ — $ 107,327 Landfill 6,118 16,517 — 22,635 Transfer 13,475 9,976 — 23,451 Transportation 47 3,040 — 3,087 Landfill gas-to-energy 246 854 — 1,100 Processing 1,808 502 21,031 23,341 Non-processing — — 34,934 34,934 Total revenues $ 61,058 $ 98,852 $ 55,965 $ 215,875 Transferred at a point-in-time $ 38 $ 487 $ 14,944 $ 15,469 Transferred over time 61,020 98,365 41,021 200,406 Total revenues $ 61,058 $ 98,852 $ 55,965 $ 215,875 Six Months Ended June 30, 2022 Eastern Western 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 Non-processing — — 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 Six Months Ended June 30, 2021 Eastern Western Resource Solutions Total Revenues Collection $ 75,440 $ 129,356 $ — $ 204,796 Landfill 11,520 30,136 — 41,656 Transfer 22,899 17,123 — 40,022 Transportation 95 5,253 — 5,348 Landfill gas-to-energy 515 1,888 — 2,403 Processing 2,934 860 38,302 42,096 Non-processing — — 69,085 69,085 Total revenues $ 113,403 $ 184,616 $ 107,387 $ 405,406 Transferred at a point-in-time $ 82 $ 988 $ 25,036 $ 26,106 Transferred over time 113,321 183,628 82,351 379,300 Total revenues $ 113,403 $ 184,616 $ 107,387 $ 405,406 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 $5,908 and $9,702 in the three and six months ended June 30, 2022, respectively, and $2,532 and $4,100 in the three and six months ended June 30, 2021, 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 any revenues in the three and six months ended June 30, 2022 or June 30, 2021 from performance obligations satisfied in previous periods. Contract receivables, which are included in Accounts receivable, net are recorded when billed or when related revenue is earned, if earlier, and represent claims against third-parties that will be settled in cash. Accounts receivable, net includes gross receivables from contracts of $111,601 and $89,232 as of June 30, 2022 and December 31, 2021, respectively. Certain customers are billed in advance and, accordingly, recognition of the related revenues is deferred as a contract liability until the services are provided and control transferred to the customer. We recognized contract liabilities of $3,733 and $3,404 as of June 30, 2022 and December 31, 2021, 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, 2021 and December 31, 2020 was recognized as revenue during the six months ended June 30, 2022 and June 30, 2021, respectively, when the services were performed.

BUSINESS COMBINATIONS

BUSINESS COMBINATIONS	6 Months Ended
	Jun. 30, 2022
Business Combination and Asset Acquisition [Abstract]
BUSINESS COMBINATIONS	BUSINESS COMBINATIONS In the six months ended June 30, 2022, we acquired the following businesses: a full service solid-waste collection, recycling and transportation business in our Resource Solutions operating segment; a closed waste-to-energy facility that is being decommissioned and rebuilt as a transfer station and four tuck-in solid waste collection businesses in our Western region; a portable toilets business in our Eastern region; and a scrap metal collection business whose assets are allocated between our Eastern region and Resource Solutions operating segments. In the six months ended June 30, 2021, we acquired two tuck-in solid waste collection businesses in our Western region, along with a septic and portable toilet business and a tuck-in solid waste collection business in our Eastern region. The operating results of these businesses are included in the accompanying unaudited consolidated statements of operations from each date of acquisition, and the purchase price has been allocated to the net assets acquired based on fair values at each date of acquisition, with the residual amounts recorded as goodwill. 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 four-year to ten-year period from the date of acquisition. All amounts recorded to goodwill are expected to be deductible for tax purposes. A summary of the purchase price paid and the purchase price allocation for acquisitions follows: Six Months Ended 2022 2021 Purchase Price: Cash used in acquisitions, net of cash acquired $ 55,053 $ 4,378 Holdbacks 3,842 505 Total consideration 58,895 4,883 Allocated as follows: Current assets 7,584 13 Property, plant and equipment: Land 2,804 — Buildings and improvements 5,308 — Equipment 6,712 1,549 Operating lease right-of-use assets 405 — Intangible assets: Covenants not-to-compete 1,415 420 Customer relationships 9,725 1,226 Other non-current assets 40 — Current liabilities (3,577) (82) Operating lease liabilities, less current portion (282) — Fair value of assets acquired and liabilities assumed 30,134 3,126 Excess purchase price allocated to goodwill $ 28,761 $ 1,757 Certain purchase price allocations 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, 2021 is as follows: Three Months Ended Six Months Ended 2022 2021 2022 2021 Revenues $ 284,314 $ 246,623 $ 525,012 $ 467,326 Operating income $ 31,776 $ 22,612 $ 42,716 $ 35,334 Net income $ 17,787 $ 9,952 $ 22,025 $ 12,457 Basic earnings per share attributable to common stockholders: Weighted average common shares outstanding 51,642 51,366 51,567 51,273 Basic earnings per common share $ 0.34 $ 0.19 $ 0.43 $ 0.24 Diluted earnings per share attributable to common stockholders: Weighted average common shares outstanding 51,781 51,546 51,720 51,466 Diluted earnings per common share $ 0.34 $ 0.19 $ 0.43 $ 0.24 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, 2021 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 a result of the integration and consolidation of the completed acquisitions.

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS	6 Months Ended
	Jun. 30, 2022
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 Adjustments to Acquisitions June 30, Eastern $ 52,072 $ 93 $ 237 $ 52,402 Western 163,728 7,350 650 171,728 Resource Solutions 17,060 21,318 — 38,378 Total $ 232,860 $ 28,761 $ 887 $ 262,508 Summaries of intangible assets by type follows: Covenants Customer Relationships Trade Names Total Balance, June 30, 2022 Intangible assets $ 30,193 $ 124,680 $ 8,350 $ 163,223 Less accumulated amortization (23,094) (40,296) (3,071) (66,461) $ 7,099 $ 84,384 $ 5,279 $ 96,762 Covenants Customer Relationships Trade Names Total Balance, December 31, 2021 Intangible assets $ 28,777 $ 115,005 $ 8,350 $ 152,132 Less accumulated amortization (22,148) (34,809) (1,452) (58,409) $ 6,629 $ 80,196 $ 6,898 $ 93,723 Intangible amortization expense was $4,262 and $8,052 during the three and six months ended June 30, 2022, respectively, and $2,015 and $4,043 during the three and six months ended June 30, 2021, respectively. A summary of intangible amortization expense estimated for the five fiscal years following fiscal year 2021 and thereafter follows: Estimated Future Amortization Expense as of June 30, 2022 Fiscal year ending December 31, 2022 $ 8,158 Fiscal year ending December 31, 2023 $ 15,600 Fiscal year ending December 31, 2024 $ 14,879 Fiscal year ending December 31, 2025 $ 13,758 Fiscal year ending December 31, 2026 $ 12,123 Thereafter $ 32,244

ACCRUED FINAL CAPPING, CLOSURE

ACCRUED FINAL CAPPING, CLOSURE AND POST CLOSURE	6 Months Ended
	Jun. 30, 2022
Asset Retirement Obligation Disclosure [Abstract]
ACCRUED FINAL CAPPING, CLOSURE AND POST CLOSURE	ACCRUED FINAL CAPPING, CLOSURE AND POST CLOSUREAccrued 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 2022 2021 Beginning balance $ 86,914 $ 82,533 Obligations incurred 2,244 2,319 Revision in estimates (1) 1,443 — Accretion expense 3,799 3,676 Obligations settled (2) (2,027) (2,969) Ending balance $ 92,373 $ 85,559 (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, 2022
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 LIBOR plus 1.375% $ 350,000 $ 350,000 Revolving credit facility due December 2026 ("Revolving Credit Facility"); bearing interest at LIBOR plus 1.375% — — Tax-Exempt Bonds: New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014 ("New York Bonds 2014R-1") due December 2044 - fixed rate interest period through 2029; bearing interest at 2.875% 25,000 25,000 New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014R-2 ("New York Bonds 2014R-2") due December 2044 - fixed rate interest period through 2026; bearing interest at 3.125% 15,000 15,000 New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2020 ("New York Bonds 2020") due September 2050 - fixed rate interest period through 2025; bearing interest at 2.750% 40,000 40,000 Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2005R-3 ("FAME Bonds 2005R-3") due January 2025 - fixed rate interest period through 2025; bearing interest at 5.25% 25,000 25,000 Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2015R-1 ("FAME Bonds 2015R-1") due August 2035 - fixed rate interest period through 2025; bearing interest at 5.125% 15,000 15,000 Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2015R-2 ("FAME Bonds 2015R-2") due August 2035 - fixed rate interest period through 2025; bearing interest at 4.375% 15,000 15,000 Vermont Economic Development Authority Solid Waste Disposal Long-Term Revenue Bonds Series 2013 ("Vermont Bonds 2013") due April 2036 - fixed rate interest period through 2028; bearing interest at 4.625% 16,000 16,000 Vermont Economic Development Authority Solid Waste Disposal Long-Term Revenue Bonds Series 2022A-1 ("Vermont Bonds 2022A-1") due June 2052 - fixed rate interest period through 2027; bearing interest at 5.00% 35,000 — Business Finance Authority of the State of New Hampshire Solid Waste Disposal Revenue Bonds Series 2013 ("New Hampshire Bonds") due April 2029 - fixed rate interest period through 2029; bearing interest at 2.95% 11,000 11,000 Other: Finance leases maturing through December 2107; bearing interest at a weighted average of 3.6% 45,889 45,724 Notes payable maturing through August 2024; bearing interest at a weighted average of 1.6% 773 4,846 Principal amount of debt 593,662 562,570 Less—unamortized debt issuance costs (1) 10,470 10,166 Debt less unamortized debt issuance costs 583,192 552,404 Less—current maturities of debt 7,636 9,901 $ 575,556 $ 542,503 (1) A summary of unamortized debt issuance costs by debt instrument follows: June 30, December 31, Revolving Credit Facility and Term Loan Facility (collectively, the "Credit Facility") $ 5,306 $ 5,884 New York Bonds 2014R-1 899 933 New York Bonds 2014R-2 238 268 New York Bonds 2020 1,194 1,283 FAME Bonds 2005R-3 219 262 FAME Bonds 2015R-1 378 413 FAME Bonds 2015R-2 231 268 Vermont Bonds 2013 405 433 Vermont Bonds 2022A-1 1,207 — New Hampshire Bonds 393 422 $ 10,470 $ 10,166 Financing Activities In the three months ended June 30, 2022, we completed the issuance of $35,000 aggregate principal amount of Vermont Bonds 2022A-1. The Vermont Bonds 2022A-1, which are unsecured and guaranteed jointly and severally, fully and unconditionally by all of our significant wholly-owned subsidiaries, accrue interest at 5.00% per annum from June 1, 2022 through May 31, 2027, at which time they may be converted to a variable interest rate period or to a new term interest rate period. The Vermont Bonds 2022A-1 mature on June 1, 2052. As of June 30, 2022, we had $1,006 of remaining cash proceeds from the issuance of the Vermont Bonds 2022A-1 included in restricted cash and assets that is restricted to finance or reimburse certain noncurrent asset costs associated with capital projects in the State of Vermont. Credit Facility As of June 30, 2022, we are party to an amended and restated credit agreement ("Credit Agreement"), which provides for a $350,000 aggregate principal amount Term Loan Facility and a $300,000 Revolving Credit Facility, with a $75,000 sublimit for letters of credit. We have the right to request, at our discretion, an increase in the amount of loans under the Credit Facility by an aggregate amount of $125,000, subject to the terms and conditions set forth in the Credit Agreement. The Credit Facility has a 5-year term that matures in December 2026 and bears interest at a rate of LIBOR plus 1.375% per annum, which will be reduced to a rate of LIBOR plus as low as 1.125% upon us reaching a consolidated net leverage ratio of less than 2.25x. The Credit Agreement contains customary benchmark replacement provisions pursuant to which, upon certain triggering events, the LIBOR benchmark used to calculate the LIBOR rate will be replaced with a secured overnight financing rate, as adjusted, on the terms and conditions in the Credit Agreement. 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, 2022, further advances were available under the Revolving Credit Facility in the amount of $271,805. The available amount is net of outstanding irrevocable letters of credit totaling $28,195, and as of June 30, 2022 no amount had been drawn. Cash Flow Hedges Our strategy to reduce exposure to interest rate risk involves entering into interest rate derivative agreements to hedge against adverse movements in interest rates related to the variable rate portion of our long-term debt. We have designated these derivative instruments as highly effective cash flow hedges, and therefore the change in their fair value is recorded in stockholders’ equity as a component of accumulated other comprehensive income (loss), net of tax and included in interest expense at the same time as interest expense is affected by the hedged transactions. Differences paid or received over the life of the agreements are recorded as additions to or reductions of interest expense on the underlying debt and included in cash flows from operating activities. As of June 30, 2022 and December 31, 2021, our active interest rate derivative agreements had total notional amounts of $190,000 and $195,000, respectively. According to the terms of the agreements, we receive interest based on the 1-month LIBOR index, in some instances restricted by a 0.0% floor, and pay interest at a weighted average rate of approximately 2.20%. The agreements mature between May 2023 and June 2027. As of December 31, 2021, we had forward starting interest rate derivative agreements with a total notional amount of $85,000 outstanding. As of June 30, 2022, we have a forward starting interest rate derivative agreement with a total notional amount of $20,000 after considering any forward starting interest rate derivative agreements that became effective in the current period. According to the terms of this agreement, we will receive interest based on the 1-month LIBOR index, restricted by a 0.0% floor, and will pay interest at a rate of 1.29%. The agreement matures in May 2028. 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 $ 1,454 $ — Interest rate swaps Other non-current assets 5,508 424 $ 6,962 $ 424 Interest rate swaps Other accrued liabilities $ — $ 3,796 Interest rate swaps Other long-term liabilities — 1,380 $ — $ 5,176 Interest rate swaps Accumulated other comprehensive income (loss), net of tax $ 6,962 $ (4,935) Interest rate swaps - tax effect Accumulated other comprehensive income (loss), net of tax (2,942) (168) $ 4,020 $ (5,103) A summary of the amount of expense on cash flow hedging relationships related to interest rate swaps reclassified from accumulated other comprehensive income (loss), net of tax into earnings follows: Three Months Ended Six Months Ended Statement of Operations Location 2022 2021 2022 2021 Interest expense $ 994 $ 1,202 $ 2,122 $ 2,347

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	6 Months Ended
	Jun. 30, 2022
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Legal Proceedings In the ordinary course of our business and as a result of the extensive governmental regulation of the solid waste industry, we are subject to various judicial and administrative proceedings involving state and local agencies. In these proceedings, an agency may seek to impose fines or to revoke or deny renewal of an operating permit held by us. From time to time, we may also be subject to actions brought by special interest or other groups, adjacent landowners or residents in connection with the permitting and licensing of landfills and transfer stations, or allegations of environmental damage or violations of the permits and licenses pursuant to which we operate. In addition, we may be named defendants in various claims and suits pending for alleged damages to persons and property, alleged violations of certain laws and alleged liabilities arising out of matters occurring during the ordinary operation of a waste management business. The plaintiffs in some actions seek unspecified damages or injunctive relief, or both. These actions fall within various procedural stages at any point in time, and some are covered in part by insurance. In accordance with FASB ASC 450 - Contingencies, we accrue for legal proceedings, inclusive of legal costs, when losses become probable and reasonably estimable. We have recorded an aggregate accrual of $1,291 relating to our outstanding legal proceedings as of June 30, 2022. As of the end of each applicable reporting period, we review each of our legal proceedings to determine whether it is probable, reasonably possible or remote that a liability has been incurred and, if it is at least reasonably possible, whether a range of loss can be reasonably estimated under the provisions of FASB ASC 450-20. In instances where we determine that a loss is probable and we can reasonably estimate a range of loss we may incur with respect to such a matter, we record an accrual for the amount within the range that constitutes our best estimate of the possible loss. If we are able to reasonably estimate a range, but no amount within the range appears to be a better estimate than any other, we record an accrual in the amount that is the low end of such range. When a loss is reasonably possible, but not probable, we will not record an accrual, but we will disclose our estimate of the possible range of loss where such estimate can be made in accordance with FASB ASC 450-20. We disclose outstanding matters that we believe could have a material adverse effect on our financial condition, results of operations or cash flows. North Country Environmental Services Expansion Permit On October 9, 2020, our subsidiary, North Country Environmental Services, Inc. ("NCES"), received a Type I-A Permit Modification (the "Permit") for Expansion in the Stage VI area of the NCES landfill located in Bethlehem, New Hampshire. On November 9, 2020, the Conservation Law Foundation ("CLF") filed an appeal of the Permit to the New Hampshire Waste Management Council (the “Council”) on the grounds it failed to meet the public benefit criteria. On January 19, 2021, CLF filed a Complaint for Injunctive Relief with the Grafton Superior Court to enjoin NCES from accepting waste pursuant to the new Permit until such a time as CLF has exhausted its appeal rights. A hearing on the Complaint for Injunctive Relief was held on March 10, 2021; the Grafton Superior Court denied the motion on May 14, 2021. CLF did not appeal this decision. The Council denied NCES’s Motion to Dismiss CLF’s appeal for lack of standing by Order dated March 17, 2021. NCES filed a Motion to Reconsider on March 26, 2021, which was denied by the Council on May 11, 2021. A prehearing conference was held and a schedule for the case was established on June 8, 2021. NCES filed a Motion to Dismiss on the merits of the appeal on June 30, 2021. On July 16, 2021, CLF filed its objection to the Motion to Dismiss, and NCES filed its reply on July 26, 2021. The Council issued an Order on September 3, 2021 granting NCES’s Motion to Dismiss, in part. CLF filed a Motion for Reconsideration on September 23, 2021, and NCES filed its objection on September 28, 2021 and CLF filed a reply on September 30, 2021. CLF’s Motion for Reconsideration was granted on November 19, 2021, and its dismissed claims reinstated. On January 14, 2022, NCES filed a Motion in Limine seeking to exclude from evidence four potential evidentiary items on the basis that those items were either not directly related, or were not included in CLF’s Notice of Appeal. On January 21, 2022, CLF filed an objection to NCES’s motion, and NCES filed a reply on January 26, 2022. On January 31, 2022, the Council issued an Order granting NCES’s Motion in Limine with respect to three of the four items it sought to exclude from evidence, and denying its motion with respect to the remaining item. On February 18 and February 22, 2022, a quorum of the Council and Hearing Officer held a hearing on the appeal. Council deliberations occurred and were concluded on February 22, 2022,with the Council ruling in favor of NCES on all motions concerning questions of fact, and indicating that a written decision incorporating the Hearing Officer’s decision as to questions of law would follow. On May 11, 2022, an Order was issued denying all of CLF’s arguments on appeal, with the exception of one; the Hearing Officer held that based on his interpretation of the relevant statute, the public benefit determination made by the New Hampshire Department of Environmental Services (“DES”), in issuing the Permit to NCES, was unlawful, and remanded the Permit to the DES with regard to this determination. DES filed a Motion for Reconsideration with the Council on May 31, 2022 (the “DES Reconsideration Motion”) and NCES filed a Motion for Rehearing on June 10, 2022 (the “NCES Rehearing Motion”). The Hearing Officer suspended his May 11, 2022 decision by Order dated June 20, 2022, pending consideration of the DES Reconsideration Motion and NCES Rehearing Motion. On June 24, 2022, CLF filed an Objection and Motion to Strike with respect to the NCES Rehearing Motion as well as an Objection to the DES Reconsideration Motion, and DES filed a Limited Objection to the NCES Rehearing Motion, each to which NCES submitted a Reply on July 6, 2022. On July 18, 2022, CLF filed a Reply in Support of its Motion to Strike and Limited Surreply in Support of Objection to the NCES Motion for Rehearing. On July 21, 2022, NCES filed an Assented to Motion for Leave to File Limited Surreply to CLF’s Motion to Strike together with a Limited Surreply to CLF’s Motion to Strike. The outcome remains pending. NCES will continue to vigorously defend against this litigation. Environmental Remediation Liabilities We are subject to liability for environmental damage, including personal injury and property damage, that our solid waste, recycling and power generation facilities may cause to neighboring property owners, particularly as a result of the contamination of drinking water sources or soil, possibly including damage resulting from conditions that existed before we acquired the facilities. We may also be subject to liability for similar claims arising from off-site environmental contamination caused by pollutants or hazardous substances if we or our predecessors arrange or arranged to transport, treat or dispose of those materials. We accrue for costs associated with environmental remediation obligations when such costs become both probable and reasonably estimable. Determining the method and ultimate cost of remediation requires that a number of assumptions be made. There can sometimes be a range of reasonable estimates of the costs associated with remediation of a site. In these cases, we use the amount within the range that constitutes our best estimate. In the early stages of the remediation process, particular components of the overall liability may not be reasonably estimable; in this instance we use the components of the liability that can be reasonably estimated as a surrogate for the liability. It is reasonably possible that we will need to adjust the liabilities recorded for remediation to reflect the effects of new or additional information, to the extent such information impacts the costs, timing or duration of the required actions. Future changes in our estimates of the cost, timing or duration of the required actions could have a material adverse effect on our consolidated financial position, results of operations and cash flows. We disclose outstanding environmental remediation matters that remain unsettled or are settled in the reporting period that we believe could have a material adverse effect on our financial condition, results of operations or cash flows. We inflate the estimated costs in current dollars to the expected time of payment and discount the total cost to present value using a risk-free interest rate. The weighted average risk-free interest rate associated with our environmental remediation liabilities as of June 30, 2022 ranges between 1.5% and 2.6%. A summary of the changes to the aggregate environmental remediation liabilities for the six months ended June 30, 2022 and 2021 follows: Six Months Ended 2022 2021 Beginning balance $ 5,887 $ 5,200 Accretion expense 54 56 Obligations settled (1) (72) (281) Ending balance 5,869 4,975 Less: current portion 280 375 Long-term portion $ 5,589 $ 4,600 (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, 2022
Equity [Abstract]
STOCKHOLDERS' EQUITY	STOCKHOLDERS' EQUITY Stock Based Compensation Shares Available For Issuance In the fiscal year ended December 31, 2016, we adopted the 2016 Incentive Plan (“2016 Plan”). Under the 2016 Plan, we may grant awards up to an aggregate amount of shares equal to the sum of: (i) 2,250 shares of Class A common stock (subject to adjustment in the event of stock splits and other similar events), plus (ii) such additional number of shares of Class A common stock (up to 2,723 shares) as is equal to the sum of the number of shares of Class A common stock that remained available for grant under the 2006 Stock Incentive Plan (“2006 Plan”) immediately prior to the expiration of the 2006 Plan and the number of shares of Class A common stock subject to awards granted under the 2006 Plan that expire, terminate or are otherwise surrendered, canceled, forfeited or repurchased by us. As of June 30, 2022, there were 868 Class A common stock equivalents available for future grant under the 2016 Plan. Stock Options Stock options are granted at a price equal to the prevailing fair value of our Class A common stock at the date of grant. Generally, stock options granted have a term not to exceed ten years and vest over a one-year to four-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, 2021 77 $ 15.68 Granted — $ — Exercised (23) $ 8.56 Forfeited — $ — Outstanding, June 30, 2022 54 $ 18.62 4.3 $ 2,946 Exercisable, June 30, 2022 46 $ 9.49 3.5 $ 2,913 Stock-based compensation expense related to stock options was $17 and $33 during the three and six months ended June 30, 2022, respectively. We did not record any stock-based compensation expense for stock options during the three and six months ended June 30, 2021. As of June 30, 2022, we had $139 of unrecognized stock-based compensation expense related to outstanding stock options to be recognized over a weighted average period of 2.1 years. During the three and six months ended June 30, 2022, the aggregate intrinsic value of stock options exercised was $1,156 and $1,467, respectively. 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 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, restricted stock unit and performance stock unit activity follows: Restricted Stock, Restricted Stock Units, and Performance Stock Units (1) Weighted Weighted Average Remaining Contractual Term (years) Aggregate Intrinsic Value Outstanding, December 31, 2021 249 $ 55.40 Granted 82 $ 94.31 Class A Common Stock Vested (63) $ 49.00 Forfeited (34) $ 67.73 Outstanding, June 30, 2022 234 $ 68.86 1.9 $ 17,031 Unvested, June 30, 2022 418 $ 68.97 1.6 $ 30,407 (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 184 shares of Class A common stock currently included in unvested. Stock-based compensation expense related to restricted stock, restricted stock units and performance stock units was $828 and $2,979 during the three and six months ended June 30, 2022, respectively, as compared to $3,044 and $5,928 during the three and six months ended June 30, 2021, respectively. During the three and six months ended June 30, 2022, the total fair value of other stock awards vested was $814 and $5,359, respectively. As of June 30, 2022, total unrecognized stock-based compensation expense related to outstanding restricted stock was $58, which will be recognized over a weighted average period of 1.5 years. As of June 30, 2022, total unrecognized stock-based compensation expense related to outstanding restricted stock units was $5,543, which will be recognized over a weighted average period of 1.9 years. As of June 30, 2022, total expected unrecognized stock-based compensation expense related to outstanding performance stock units was $6,882 to be recognized over a weighted average period of 1.8 years. We also recorded $93 and $166 of stock-based compensation expense related to our Amended and Restated 1997 Employee Stock Purchase Plan during the three and six months ended June 30, 2022, respectively, as compared to $72 and $128 during the three and six months ended June 30, 2021, respectively. Accumulated Other Comprehensive Income (Loss), Net of Tax A summary of the changes in the balances of each component of accumulated other comprehensive income (loss), net of tax follows: Interest Rate Swaps Balance, December 31, 2021 $ (5,103) Other comprehensive income before reclassifications 9,774 Amounts reclassified from accumulated other comprehensive income (loss) 2,122 Income tax provision related to items of other comprehensive income (2,773) Net current-period other comprehensive income 9,123 Balance, June 30, 2022 $ 4,020 A summary of reclassifications out of accumulated other comprehensive income (loss), net of tax follows: Three Months Ended Six Months Ended 2022 2021 2022 2021 Details About Accumulated Other Comprehensive Income (Loss), Net of Tax Components Amounts Reclassified Out of Accumulated Other Comprehensive Income (Loss), Net of Tax Affected Line Item in the Consolidated Interest rate swaps $ 994 $ 1,202 $ 2,122 $ 2,347 Interest expense (994) (1,202) (2,122) (2,347) Income before income taxes — (142) (190) (269) Provision for income taxes $ (994) $ (1,060) $ (1,932) $ (2,078) Net income

EARNINGS PER SHARE

EARNINGS PER SHARE	6 Months Ended
	Jun. 30, 2022
Earnings Per Share [Abstract]
EARNINGS PER SHARE	EARNINGS PER SHAREBasic earnings per share is computed by dividing net income by the weighted average number of common shares outstanding during the period. Diluted earnings per share is calculated based on the combined weighted average number of common shares and potentially dilutive shares, which include the assumed exercise of employee stock options, unvested restricted stock awards, unvested restricted stock units and unvested performance stock units, including market-based performance units based on the expected achievement of performance targets. In computing diluted earnings per share, we utilize the treasury stock method. A summary of the numerator and denominators used in the computation of earnings per share follows: Three Months Ended Six Months Ended 2022 2021 2022 2021 Numerator: Net income $ 17,796 $ 11,783 $ 21,986 $ 16,094 Denominators: Number of shares outstanding, end of period: Class A common stock 50,690 50,398 50,690 50,398 Class B common stock 988 988 988 988 Unvested restricted stock (2) (2) (2) (2) Effect of weighted average shares outstanding (34) (18) (109) (111) Basic weighted average common shares outstanding 51,642 51,366 51,567 51,273 Impact of potentially dilutive securities: Dilutive effect of stock options and other stock awards 139 180 153 193 Diluted weighted average common shares outstanding 51,781 51,546 51,720 51,466 Anti-dilutive potentially issuable shares 70 — 70 48

OTHER ITEMS AND CHARGES

OTHER ITEMS AND CHARGES	6 Months Ended
	Jun. 30, 2022
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, 2022, we recorded charges of $1,019 and $3,062, respectively, and in the three and six months ended June 30, 2021, we recorded charges of $1,632 and $2,046, respectively, comprised primarily of legal, consulting and other similar costs associated with due diligence and the acquisition and integration of acquired businesses or select development projects.

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	6 Months Ended
	Jun. 30, 2022
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, restricted cash, 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 the one-month LIBOR yield curves that are observable at commonly quoted intervals for the full term of the swaps. We recognize all derivatives accounted for on the balance sheet at fair value. 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, 2022 Using: Quoted Prices in Significant Other Significant Assets: Restricted investment securities - landfill closure $ 1,799 $ — $ — Interest rate swaps — 6,962 — $ 1,799 $ 6,962 $ — Fair Value Measurement at December 31, 2021 Using: Quoted Prices in Significant Other Significant Assets: Restricted investment securities - landfill closure $ 2,122 $ — $ — Interest rate swaps — 424 — $ 2,122 $ 424 $ — Liabilities: Interest rate swaps $ — $ 5,176 $ — Fair Value of Debt As of June 30, 2022, 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 $189,558 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, 2022, the carrying value of our Term Loan Facility was $350,000 and the carrying value of our Revolving Credit Facility was $0. 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, 2022
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 Western and Eastern regions. Revenues associated with our solid waste operations are derived mainly from solid waste collection, transfer, transportation and disposal, landfill gas-to-energy, processing, and recycling services in the northeastern United States. Our Resource Solutions operating segment leverages our core competencies in materials processing, industrial recycling, organics and resource management service offerings to deliver a comprehensive solution for our larger commercial, municipal, institutional and industrial customers that have more diverse waste and recycling needs. Revenues associated with our Resource Solutions operations are derived from two lines-of-service: processing and non-processing. Revenues from processing services are derived from municipalities and customers in the form of processing fees, tipping fees, commodity sales, and organic material sales. Revenues from non-processing services 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, 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 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 Three Months Ended June 30, 2021 Segment Outside Inter-company Depreciation and Operating Total Eastern $ 61,058 $ 16,128 $ 7,313 $ 3,781 $ 226,157 Western 98,852 33,566 15,089 14,900 654,314 Resource Solutions 55,965 1,277 1,548 3,651 95,664 Corporate entities — — 387 (386) 251,698 Eliminations — (50,971) — — — $ 215,875 $ — $ 24,337 $ 21,946 $ 1,227,833 Six Months Ended June 30, 2022 Segment Outside Inter-company Depreciation and Operating Total assets Eastern $ 158,582 $ 38,815 $ 22,988 $ 3,920 $ 362,942 Western 210,723 71,983 30,598 29,160 697,252 Resource Solutions 148,388 1,095 5,872 9,928 189,820 Corporate Entities — — 1,121 (1,121) 120,705 Eliminations — (111,893) — — — Total $ 517,693 $ — $ 60,579 $ 41,887 $ 1,370,719 Six Months Ended June 30, 2021 Segment Outside Inter-company Depreciation and Operating Total assets Eastern $ 113,403 $ 28,554 $ 13,935 $ 6,027 $ 226,157 Western 184,616 62,248 29,128 22,657 654,314 Resource Solutions 107,387 3,180 3,116 6,113 95,664 Corporate Entities — — 840 (842) 251,698 Eliminations — (93,982) — — — Total $ 405,406 $ — $ 47,019 $ 33,955 $ 1,227,833 A summary of our revenues attributable to services provided follows: Three Months Ended Six Months Ended 2022 2021 2022 2021 Collection $ 137,261 $ 107,327 $ 256,793 $ 204,796 Disposal 60,204 49,173 103,356 87,026 Power generation 1,753 1,100 4,407 2,403 Processing 2,929 2,310 4,749 3,794 Solid waste operations 202,147 159,910 369,305 298,019 Processing 33,867 21,031 61,263 38,302 Non-processing 47,652 34,934 87,125 69,085 Resource Solutions operations 81,519 55,965 148,388 107,387 Total revenues $ 283,666 $ 215,875 $ 517,693 $ 405,406

ACCOUNTING CHANGES (Policies)

ACCOUNTING CHANGES (Policies)	6 Months Ended
	Jun. 30, 2022
Accounting Changes and Error Corrections [Abstract]
Basis of Accounting	Casella Waste Systems, Inc. (“Parent”), and its subsidiaries (collectively, “we”, “us” or “our”), is a regional, vertically integrated solid waste services company. We provide resource management expertise and services to residential, commercial, municipal, institutional and industrial customers, primarily in the areas of solid waste collection and disposal, transfer, recycling and organics services. We provide integrated solid waste services in seven states: Vermont, New Hampshire, New York, Massachusetts, Connecticut, Maine and Pennsylvania, with our headquarters located in Rutland, Vermont. We manage our solid waste operations on a geographic basis through two regional operating segments, the Eastern and Western regions, each of which provides a full range of solid waste services. We manage our resource-renewal operations through the Resource Solutions operating segment, which leverages our core competencies in materials processing, industrial recycling, organics and resource management service offerings to deliver a comprehensive solution for our larger commercial, municipal, institutional and industrial customers that have more diverse waste and recycling needs. Legal, tax, information technology, human resources, certain finance and accounting and other administrative functions are included in our Corporate Entities segment. The accompanying unaudited consolidated financial statements, which include the accounts of the Parent and our wholly-owned subsidiaries, have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). All significant intercompany accounts and transactions are eliminated in consolidation. Investments in entities in which we do not have a controlling financial interest are accounted for under either the equity method or the cost method of accounting, as appropriate. Our significant accounting policies are more fully discussed in Item 8, " Financial Statements and Supplementary Data " of our Annual Report on Form 10-K for the fiscal year ended December 31, 2021 ("fiscal year 2021"), which was filed with the SEC on February 18, 2022.
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, 2022 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, 2022 through the date of filing of the consolidated financial statements with the SEC on this Quarterly Report on Form 10-Q. We have determined that there are no subsequent events that require disclosure in this Quarterly Report on Form 10-Q.
Accounting Standards Adopted and Pending Adoption	A table providing a brief description of recent Accounting Standards Updates ("ASUs") to the Accounting Standards Codification ("ASC") issued by the Financial Accounting Standards Board (“FASB”) that are pending adoption and deemed to have a possible material impact on our consolidated financial statements based on current account balances and activity follows: Standard Description Effect on the Financial Statements or Other Accounting standards issued pending adoption ASU No. 2020-04: Reference Rate Reform (Topic 848), as amended through January 2021 Provides temporary optional guidance to ease the potential burden in applying GAAP to contract modifications and hedging relationships that reference London Inter-Bank Offered Rate ("LIBOR") or another reference rate expected to be discontinued, subject to meeting certain criteria. We currently have interest rate derivative agreements with hedging relationships that reference LIBOR. 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. We are currently assessing the provisions of this guidance, and reviewing and updating our existing contracts, as applicable, for transition or fallback language that specifies how a replacement rate for LIBOR will be identified. We are also no longer using LIBOR as a reference rate for any new contracts. We do not expect that the adoption of this guidance will have a material impact on our consolidated financial statements and related disclosures. This guidance will be in effect from March 12, 2020 through December 31, 2022. See Note 7, Debt for further disclosure over our interest rate derivative agreements and debt instruments that reference LIBOR. ASU No. 2021-08: Accounting for Contract Assets and Contract Liabilities from Contracts with Customers (Topic 805) Requires entities to apply ASC 606 to recognize and measure contract assets and contract liabilities in a business combination. This guidance improves comparability after the business combination by providing consistent recognition and measurement guidance for revenue contracts with customers acquired in a business combination and revenue contracts with customers not acquired in a business combination. We have made in the past, and we may make in the future, acquisitions to densify existing operations, expand service areas, and grow services for our customers, and these acquisitions may include contract assets or contract liabilities. We do not expect that the adoption of this guidance will have a material impact on our consolidated financial statements and related disclosures. This guidance is effective January 1, 2023 with early adoption permitted.
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
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 Western and Eastern regions. Revenues associated with our solid waste operations are derived mainly from solid waste collection, transfer, transportation and disposal, landfill gas-to-energy, processing, and recycling services in the northeastern United States. Our Resource Solutions operating segment leverages our core competencies in materials processing, industrial recycling, organics and resource management service offerings to deliver a comprehensive solution for our larger commercial, municipal, institutional and industrial customers that have more diverse waste and recycling needs. Revenues associated with our Resource Solutions operations are derived from two lines-of-service: processing and non-processing. Revenues from processing services are derived from municipalities and customers in the form of processing fees, tipping fees, commodity sales, and organic material sales. Revenues from non-processing services 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, 2022
Accounting Changes and Error Corrections [Abstract]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	A table providing a brief description of recent Accounting Standards Updates ("ASUs") to the Accounting Standards Codification ("ASC") issued by the Financial Accounting Standards Board (“FASB”) that are pending adoption and deemed to have a possible material impact on our consolidated financial statements based on current account balances and activity follows: Standard Description Effect on the Financial Statements or Other Accounting standards issued pending adoption ASU No. 2020-04: Reference Rate Reform (Topic 848), as amended through January 2021 Provides temporary optional guidance to ease the potential burden in applying GAAP to contract modifications and hedging relationships that reference London Inter-Bank Offered Rate ("LIBOR") or another reference rate expected to be discontinued, subject to meeting certain criteria. We currently have interest rate derivative agreements with hedging relationships that reference LIBOR. 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. We are currently assessing the provisions of this guidance, and reviewing and updating our existing contracts, as applicable, for transition or fallback language that specifies how a replacement rate for LIBOR will be identified. We are also no longer using LIBOR as a reference rate for any new contracts. We do not expect that the adoption of this guidance will have a material impact on our consolidated financial statements and related disclosures. This guidance will be in effect from March 12, 2020 through December 31, 2022. See Note 7, Debt for further disclosure over our interest rate derivative agreements and debt instruments that reference LIBOR. ASU No. 2021-08: Accounting for Contract Assets and Contract Liabilities from Contracts with Customers (Topic 805) Requires entities to apply ASC 606 to recognize and measure contract assets and contract liabilities in a business combination. This guidance improves comparability after the business combination by providing consistent recognition and measurement guidance for revenue contracts with customers acquired in a business combination and revenue contracts with customers not acquired in a business combination. We have made in the past, and we may make in the future, acquisitions to densify existing operations, expand service areas, and grow services for our customers, and these acquisitions may include contract assets or contract liabilities. We do not expect that the adoption of this guidance will have a material impact on our consolidated financial statements and related disclosures. This guidance is effective January 1, 2023 with early adoption permitted.

REVENUE RECOGNITION (Tables)

REVENUE RECOGNITION (Tables)	6 Months Ended
	Jun. 30, 2022
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, 2022 and 2021: Three Months Ended June 30, 2022 Eastern Western Resource Solutions Total Revenues Collection $ 59,299 $ 77,962 $ — $ 137,261 Landfill 6,542 18,599 — 25,141 Transfer 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 Non-processing — — 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 Three Months Ended June 30, 2021 Eastern Western Resource Solutions Total Revenues Collection $ 39,364 $ 67,963 $ — $ 107,327 Landfill 6,118 16,517 — 22,635 Transfer 13,475 9,976 — 23,451 Transportation 47 3,040 — 3,087 Landfill gas-to-energy 246 854 — 1,100 Processing 1,808 502 21,031 23,341 Non-processing — — 34,934 34,934 Total revenues $ 61,058 $ 98,852 $ 55,965 $ 215,875 Transferred at a point-in-time $ 38 $ 487 $ 14,944 $ 15,469 Transferred over time 61,020 98,365 41,021 200,406 Total revenues $ 61,058 $ 98,852 $ 55,965 $ 215,875 Six Months Ended June 30, 2022 Eastern Western 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 Non-processing — — 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 Six Months Ended June 30, 2021 Eastern Western Resource Solutions Total Revenues Collection $ 75,440 $ 129,356 $ — $ 204,796 Landfill 11,520 30,136 — 41,656 Transfer 22,899 17,123 — 40,022 Transportation 95 5,253 — 5,348 Landfill gas-to-energy 515 1,888 — 2,403 Processing 2,934 860 38,302 42,096 Non-processing — — 69,085 69,085 Total revenues $ 113,403 $ 184,616 $ 107,387 $ 405,406 Transferred at a point-in-time $ 82 $ 988 $ 25,036 $ 26,106 Transferred over time 113,321 183,628 82,351 379,300 Total revenues $ 113,403 $ 184,616 $ 107,387 $ 405,406

BUSINESS COMBINATIONS (Tables)

BUSINESS COMBINATIONS (Tables)	6 Months Ended
	Jun. 30, 2022
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 2022 2021 Purchase Price: Cash used in acquisitions, net of cash acquired $ 55,053 $ 4,378 Holdbacks 3,842 505 Total consideration 58,895 4,883 Allocated as follows: Current assets 7,584 13 Property, plant and equipment: Land 2,804 — Buildings and improvements 5,308 — Equipment 6,712 1,549 Operating lease right-of-use assets 405 — Intangible assets: Covenants not-to-compete 1,415 420 Customer relationships 9,725 1,226 Other non-current assets 40 — Current liabilities (3,577) (82) Operating lease liabilities, less current portion (282) — Fair value of assets acquired and liabilities assumed 30,134 3,126 Excess purchase price allocated to goodwill $ 28,761 $ 1,757
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, 2021 is as follows: Three Months Ended Six Months Ended 2022 2021 2022 2021 Revenues $ 284,314 $ 246,623 $ 525,012 $ 467,326 Operating income $ 31,776 $ 22,612 $ 42,716 $ 35,334 Net income $ 17,787 $ 9,952 $ 22,025 $ 12,457 Basic earnings per share attributable to common stockholders: Weighted average common shares outstanding 51,642 51,366 51,567 51,273 Basic earnings per common share $ 0.34 $ 0.19 $ 0.43 $ 0.24 Diluted earnings per share attributable to common stockholders: Weighted average common shares outstanding 51,781 51,546 51,720 51,466 Diluted earnings per common share $ 0.34 $ 0.19 $ 0.43 $ 0.24

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS (Tables)	6 Months Ended
	Jun. 30, 2022
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 Adjustments to Acquisitions June 30, Eastern $ 52,072 $ 93 $ 237 $ 52,402 Western 163,728 7,350 650 171,728 Resource Solutions 17,060 21,318 — 38,378 Total $ 232,860 $ 28,761 $ 887 $ 262,508
Summary of Intangible Assets by Type	Summaries of intangible assets by type follows: Covenants Customer Relationships Trade Names Total Balance, June 30, 2022 Intangible assets $ 30,193 $ 124,680 $ 8,350 $ 163,223 Less accumulated amortization (23,094) (40,296) (3,071) (66,461) $ 7,099 $ 84,384 $ 5,279 $ 96,762 Covenants Customer Relationships Trade Names Total Balance, December 31, 2021 Intangible assets $ 28,777 $ 115,005 $ 8,350 $ 152,132 Less accumulated amortization (22,148) (34,809) (1,452) (58,409) $ 6,629 $ 80,196 $ 6,898 $ 93,723
Summary of Intangible Amortization Expense Estimated	A summary of intangible amortization expense estimated for the five fiscal years following fiscal year 2021 and thereafter follows: Estimated Future Amortization Expense as of June 30, 2022 Fiscal year ending December 31, 2022 $ 8,158 Fiscal year ending December 31, 2023 $ 15,600 Fiscal year ending December 31, 2024 $ 14,879 Fiscal year ending December 31, 2025 $ 13,758 Fiscal year ending December 31, 2026 $ 12,123 Thereafter $ 32,244

ACCRUED FINAL CAPPING, CLOSUR_2

ACCRUED FINAL CAPPING, CLOSURE AND POST CLOSURE (Tables)	6 Months Ended
	Jun. 30, 2022
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 2022 2021 Beginning balance $ 86,914 $ 82,533 Obligations incurred 2,244 2,319 Revision in estimates (1) 1,443 — Accretion expense 3,799 3,676 Obligations settled (2) (2,027) (2,969) Ending balance $ 92,373 $ 85,559 (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, 2022
Debt And Derivatives Disclosure [Abstract]
Summary 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 LIBOR plus 1.375% $ 350,000 $ 350,000 Revolving credit facility due December 2026 ("Revolving Credit Facility"); bearing interest at LIBOR plus 1.375% — — Tax-Exempt Bonds: New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014 ("New York Bonds 2014R-1") due December 2044 - fixed rate interest period through 2029; bearing interest at 2.875% 25,000 25,000 New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014R-2 ("New York Bonds 2014R-2") due December 2044 - fixed rate interest period through 2026; bearing interest at 3.125% 15,000 15,000 New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2020 ("New York Bonds 2020") due September 2050 - fixed rate interest period through 2025; bearing interest at 2.750% 40,000 40,000 Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2005R-3 ("FAME Bonds 2005R-3") due January 2025 - fixed rate interest period through 2025; bearing interest at 5.25% 25,000 25,000 Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2015R-1 ("FAME Bonds 2015R-1") due August 2035 - fixed rate interest period through 2025; bearing interest at 5.125% 15,000 15,000 Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2015R-2 ("FAME Bonds 2015R-2") due August 2035 - fixed rate interest period through 2025; bearing interest at 4.375% 15,000 15,000 Vermont Economic Development Authority Solid Waste Disposal Long-Term Revenue Bonds Series 2013 ("Vermont Bonds 2013") due April 2036 - fixed rate interest period through 2028; bearing interest at 4.625% 16,000 16,000 Vermont Economic Development Authority Solid Waste Disposal Long-Term Revenue Bonds Series 2022A-1 ("Vermont Bonds 2022A-1") due June 2052 - fixed rate interest period through 2027; bearing interest at 5.00% 35,000 — Business Finance Authority of the State of New Hampshire Solid Waste Disposal Revenue Bonds Series 2013 ("New Hampshire Bonds") due April 2029 - fixed rate interest period through 2029; bearing interest at 2.95% 11,000 11,000 Other: Finance leases maturing through December 2107; bearing interest at a weighted average of 3.6% 45,889 45,724 Notes payable maturing through August 2024; bearing interest at a weighted average of 1.6% 773 4,846 Principal amount of debt 593,662 562,570 Less—unamortized debt issuance costs (1) 10,470 10,166 Debt less unamortized debt issuance costs 583,192 552,404 Less—current maturities of debt 7,636 9,901 $ 575,556 $ 542,503 (1) A summary of unamortized debt issuance costs by debt instrument follows: June 30, December 31, Revolving Credit Facility and Term Loan Facility (collectively, the "Credit Facility") $ 5,306 $ 5,884 New York Bonds 2014R-1 899 933 New York Bonds 2014R-2 238 268 New York Bonds 2020 1,194 1,283 FAME Bonds 2005R-3 219 262 FAME Bonds 2015R-1 378 413 FAME Bonds 2015R-2 231 268 Vermont Bonds 2013 405 433 Vermont Bonds 2022A-1 1,207 — New Hampshire Bonds 393 422 $ 10,470 $ 10,166
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 $ 1,454 $ — Interest rate swaps Other non-current assets 5,508 424 $ 6,962 $ 424 Interest rate swaps Other accrued liabilities $ — $ 3,796 Interest rate swaps Other long-term liabilities — 1,380 $ — $ 5,176 Interest rate swaps Accumulated other comprehensive income (loss), net of tax $ 6,962 $ (4,935) Interest rate swaps - tax effect Accumulated other comprehensive income (loss), net of tax (2,942) (168) $ 4,020 $ (5,103) A summary of the amount of expense on cash flow hedging relationships related to interest rate swaps reclassified from accumulated other comprehensive income (loss), net of tax into earnings follows: Three Months Ended Six Months Ended Statement of Operations Location 2022 2021 2022 2021 Interest expense $ 994 $ 1,202 $ 2,122 $ 2,347

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	6 Months Ended
	Jun. 30, 2022
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, 2022 and 2021 follows: Six Months Ended 2022 2021 Beginning balance $ 5,887 $ 5,200 Accretion expense 54 56 Obligations settled (1) (72) (281) Ending balance 5,869 4,975 Less: current portion 280 375 Long-term portion $ 5,589 $ 4,600 (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, 2022
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, 2021 77 $ 15.68 Granted — $ — Exercised (23) $ 8.56 Forfeited — $ — Outstanding, June 30, 2022 54 $ 18.62 4.3 $ 2,946 Exercisable, June 30, 2022 46 $ 9.49 3.5 $ 2,913
Summary of Restricted Stock, Restricted Stock Unit and Performance Stock Unit Activity	A summary of restricted stock, restricted stock unit and performance stock unit activity follows: Restricted Stock, Restricted Stock Units, and Performance Stock Units (1) Weighted Weighted Average Remaining Contractual Term (years) Aggregate Intrinsic Value Outstanding, December 31, 2021 249 $ 55.40 Granted 82 $ 94.31 Class A Common Stock Vested (63) $ 49.00 Forfeited (34) $ 67.73 Outstanding, June 30, 2022 234 $ 68.86 1.9 $ 17,031 Unvested, June 30, 2022 418 $ 68.97 1.6 $ 30,407 (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 184 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 (loss), net of tax follows: Interest Rate Swaps Balance, December 31, 2021 $ (5,103) Other comprehensive income before reclassifications 9,774 Amounts reclassified from accumulated other comprehensive income (loss) 2,122 Income tax provision related to items of other comprehensive income (2,773) Net current-period other comprehensive income 9,123 Balance, June 30, 2022 $ 4,020
Summary of Reclassifications Out of Accumulated Other Comprehensive Loss	A summary of reclassifications out of accumulated other comprehensive income (loss), net of tax follows: Three Months Ended Six Months Ended 2022 2021 2022 2021 Details About Accumulated Other Comprehensive Income (Loss), Net of Tax Components Amounts Reclassified Out of Accumulated Other Comprehensive Income (Loss), Net of Tax Affected Line Item in the Consolidated Interest rate swaps $ 994 $ 1,202 $ 2,122 $ 2,347 Interest expense (994) (1,202) (2,122) (2,347) Income before income taxes — (142) (190) (269) Provision for income taxes $ (994) $ (1,060) $ (1,932) $ (2,078) Net income

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	6 Months Ended
	Jun. 30, 2022
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 2022 2021 2022 2021 Numerator: Net income $ 17,796 $ 11,783 $ 21,986 $ 16,094 Denominators: Number of shares outstanding, end of period: Class A common stock 50,690 50,398 50,690 50,398 Class B common stock 988 988 988 988 Unvested restricted stock (2) (2) (2) (2) Effect of weighted average shares outstanding (34) (18) (109) (111) Basic weighted average common shares outstanding 51,642 51,366 51,567 51,273 Impact of potentially dilutive securities: Dilutive effect of stock options and other stock awards 139 180 153 193 Diluted weighted average common shares outstanding 51,781 51,546 51,720 51,466 Anti-dilutive potentially issuable shares 70 — 70 48

FAIR VALUE OF FINANCIAL INSTR_2

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	6 Months Ended
	Jun. 30, 2022
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, 2022 Using: Quoted Prices in Significant Other Significant Assets: Restricted investment securities - landfill closure $ 1,799 $ — $ — Interest rate swaps — 6,962 — $ 1,799 $ 6,962 $ — Fair Value Measurement at December 31, 2021 Using: Quoted Prices in Significant Other Significant Assets: Restricted investment securities - landfill closure $ 2,122 $ — $ — Interest rate swaps — 424 — $ 2,122 $ 424 $ — Liabilities: Interest rate swaps $ — $ 5,176 $ —

SEGMENT REPORTING (Tables)

SEGMENT REPORTING (Tables)	6 Months Ended
	Jun. 30, 2022
Segment Reporting [Abstract]
Summary of Segment Reporting Information by Segment	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 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 Three Months Ended June 30, 2021 Segment Outside Inter-company Depreciation and Operating Total Eastern $ 61,058 $ 16,128 $ 7,313 $ 3,781 $ 226,157 Western 98,852 33,566 15,089 14,900 654,314 Resource Solutions 55,965 1,277 1,548 3,651 95,664 Corporate entities — — 387 (386) 251,698 Eliminations — (50,971) — — — $ 215,875 $ — $ 24,337 $ 21,946 $ 1,227,833 Six Months Ended June 30, 2022 Segment Outside Inter-company Depreciation and Operating Total assets Eastern $ 158,582 $ 38,815 $ 22,988 $ 3,920 $ 362,942 Western 210,723 71,983 30,598 29,160 697,252 Resource Solutions 148,388 1,095 5,872 9,928 189,820 Corporate Entities — — 1,121 (1,121) 120,705 Eliminations — (111,893) — — — Total $ 517,693 $ — $ 60,579 $ 41,887 $ 1,370,719 Six Months Ended June 30, 2021 Segment Outside Inter-company Depreciation and Operating Total assets Eastern $ 113,403 $ 28,554 $ 13,935 $ 6,027 $ 226,157 Western 184,616 62,248 29,128 22,657 654,314 Resource Solutions 107,387 3,180 3,116 6,113 95,664 Corporate Entities — — 840 (842) 251,698 Eliminations — (93,982) — — — Total $ 405,406 $ — $ 47,019 $ 33,955 $ 1,227,833
Summary of Revenue Attributable to Services	A summary of our revenues attributable to services provided follows: Three Months Ended Six Months Ended 2022 2021 2022 2021 Collection $ 137,261 $ 107,327 $ 256,793 $ 204,796 Disposal 60,204 49,173 103,356 87,026 Power generation 1,753 1,100 4,407 2,403 Processing 2,929 2,310 4,749 3,794 Solid waste operations 202,147 159,910 369,305 298,019 Processing 33,867 21,031 61,263 38,302 Non-processing 47,652 34,934 87,125 69,085 Resource Solutions operations 81,519 55,965 148,388 107,387 Total revenues $ 283,666 $ 215,875 $ 517,693 $ 405,406

BASIS OF PRESENTATION (Details)

BASIS OF PRESENTATION (Details)	6 Months Ended
	Jun. 30, 2022 regionalOperatingSegment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of regional operating segments	2

REVENUE RECOGNITION - Disaggreg

REVENUE RECOGNITION - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation of Revenue [Line Items]
Total revenues	$ 283,666	$ 215,875	$ 517,693	$ 405,406
Collection
Disaggregation of Revenue [Line Items]
Total revenues	137,261	107,327	256,793	204,796
Landfill
Disaggregation of Revenue [Line Items]
Total revenues	25,141	22,635	44,706	41,656
Transfer
Disaggregation of Revenue [Line Items]
Total revenues	29,274	23,451	48,730	40,022
Transportation
Disaggregation of Revenue [Line Items]
Total revenues	5,789	3,087	9,920	5,348
Landfill gas-to-energy
Disaggregation of Revenue [Line Items]
Total revenues	1,753	1,100	4,407	2,403
Processing
Disaggregation of Revenue [Line Items]
Total revenues	36,796	23,341	66,012	42,096
Non-processing
Disaggregation of Revenue [Line Items]
Total revenues	47,652	34,934	87,125	69,085
Transferred at a point-in-time
Disaggregation of Revenue [Line Items]
Total revenues	19,447	15,469	35,164	26,106
Transferred over time
Disaggregation of Revenue [Line Items]
Total revenues	264,219	200,406	482,529	379,300
Eastern
Disaggregation of Revenue [Line Items]
Total revenues	87,263	61,058	158,582	113,403
Eastern | Collection
Disaggregation of Revenue [Line Items]
Total revenues	59,299	39,364	110,796	75,440
Eastern | Landfill
Disaggregation of Revenue [Line Items]
Total revenues	6,542	6,118	11,918	11,520
Eastern | Transfer
Disaggregation of Revenue [Line Items]
Total revenues	17,292	13,475	28,905	22,899
Eastern | Transportation
Disaggregation of Revenue [Line Items]
Total revenues	1,765	47	3,238	95
Eastern | Landfill gas-to-energy
Disaggregation of Revenue [Line Items]
Total revenues	249	246	522	515
Eastern | Processing
Disaggregation of Revenue [Line Items]
Total revenues	2,116	1,808	3,203	2,934
Eastern | Non-processing
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	117	38	236	82
Eastern | Transferred over time
Disaggregation of Revenue [Line Items]
Total revenues	87,146	61,020	158,346	113,321
Western
Disaggregation of Revenue [Line Items]
Total revenues	114,884	98,852	210,723	184,616
Western | Collection
Disaggregation of Revenue [Line Items]
Total revenues	77,962	67,963	145,997	129,356
Western | Landfill
Disaggregation of Revenue [Line Items]
Total revenues	18,599	16,517	32,788	30,136
Western | Transfer
Disaggregation of Revenue [Line Items]
Total revenues	11,982	9,976	19,825	17,123
Western | Transportation
Disaggregation of Revenue [Line Items]
Total revenues	4,024	3,040	6,682	5,253
Western | Landfill gas-to-energy
Disaggregation of Revenue [Line Items]
Total revenues	1,504	854	3,885	1,888
Western | Processing
Disaggregation of Revenue [Line Items]
Total revenues	813	502	1,546	860
Western | Non-processing
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	517	487	1,028	988
Western | Transferred over time
Disaggregation of Revenue [Line Items]
Total revenues	114,367	98,365	209,695	183,628
Resource Solutions
Disaggregation of Revenue [Line Items]
Total revenues	81,519	55,965	148,388	107,387
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
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	33,867	21,031	61,263	38,302
Resource Solutions | Non-processing
Disaggregation of Revenue [Line Items]
Total revenues	47,652	34,934	87,125	69,085
Resource Solutions | Transferred at a point-in-time
Disaggregation of Revenue [Line Items]
Total revenues	18,813	14,944	33,900	25,036
Resource Solutions | Transferred over time
Disaggregation of Revenue [Line Items]
Total revenues	$ 62,706	$ 41,021	$ 114,488	$ 82,351

REVENUE RECOGNITION - Narrative

REVENUE RECOGNITION - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Rebates	$ (283,666,000)	$ (215,875,000)	$ (517,693,000)	$ (405,406,000)
Revenue recognized fro performance obligation satisfied in previous period	0	0	0	0
Gross receivables from contracts	111,601,000		111,601,000		$ 89,232,000
Contract liabilities	3,733,000		3,733,000		$ 3,404,000
Rebate for Recycled or Returned Organic Materials
Disaggregation of Revenue [Line Items]
Rebates	$ 5,908,000	$ 2,532,000	$ 9,702,000	$ 4,100,000

BUSINESS COMBINATIONS - Narrati

BUSINESS COMBINATIONS - Narrative (Details) - business	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Minimum
Business Acquisition [Line Items]
Useful life of finite lived intangible assets (in years)	4 years
Maximum
Business Acquisition [Line Items]
Useful life of finite lived intangible assets (in years)	10 years
Western | Tuck-in Solid Waste Collection Business
Business Acquisition [Line Items]
Number of businesses acquired	4	2

BUSINESS COMBINATIONS - Summary

BUSINESS COMBINATIONS - Summary of Purchase Price Paid for Acquisitions (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Purchase Price:
Cash used in acquisitions, net of cash acquired	$ 56,250	$ 5,481
Allocated as follows:
Excess purchase price allocated to goodwill	262,508		$ 232,860
Waste Collection Acquisitions
Purchase Price:
Cash used in acquisitions, net of cash acquired	55,053	4,378
Holdbacks	3,842	505
Total consideration	58,895	4,883
Allocated as follows:
Current assets	7,584	13
Land	2,804	0
Buildings and improvements	5,308	0
Equipment	6,712	1,549
Operating lease right-of-use assets	405	0
Other non-current assets	40	0
Current liabilities	(3,577)	(82)
Operating lease liabilities, less current portion	(282)	0
Fair value of assets acquired and liabilities assumed	30,134	3,126
Excess purchase price allocated to goodwill	28,761	1,757
Waste Collection Acquisitions | Covenants not-to-compete
Allocated as follows:
Intangible assets:	1,415	420
Waste Collection Acquisitions | Customer Relationships
Allocated as follows:
Intangible assets:	$ 9,725	$ 1,226

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, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Business Combination and Asset Acquisition [Abstract]
Revenues	$ 284,314	$ 246,623	$ 525,012	$ 467,326
Operating income	31,776	22,612	42,716	35,334
Net income	$ 17,787	$ 9,952	$ 22,025	$ 12,457
Weighted average common shares outstanding, basic (in shares)	51,642	51,366	51,567	51,273
Basic earnings per common share (in dollars per share)	$ 0.34	$ 0.19	$ 0.43	$ 0.24
Weighted average common shares outstanding, diluted (in shares)	51,781	51,546	51,720	51,466
Diluted earnings per common share (in dollars per share)	$ 0.34	$ 0.19	$ 0.43	$ 0.24

GOODWILL AND INTANGIBLE ASSET_2

GOODWILL AND INTANGIBLE ASSETS - Summary of Goodwill Activity (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2022 USD ($)
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 232,860
Acquisitions	28,761
Adjustments to Acquisitions	887
Goodwill, ending balance	262,508
Eastern
Goodwill [Roll Forward]
Goodwill, beginning balance	52,072
Acquisitions	93
Adjustments to Acquisitions	237
Goodwill, ending balance	52,402
Western
Goodwill [Roll Forward]
Goodwill, beginning balance	163,728
Acquisitions	7,350
Adjustments to Acquisitions	650
Goodwill, ending balance	171,728
Resource Solutions
Goodwill [Roll Forward]
Goodwill, beginning balance	17,060
Acquisitions	21,318
Adjustments to Acquisitions	0
Goodwill, ending balance	$ 38,378

GOODWILL AND INTANGIBLE ASSET_3

GOODWILL AND INTANGIBLE ASSETS - Summary of Intangible Assets by Type (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Intangible assets	$ 163,223	$ 152,132
Less accumulated amortization	(66,461)	(58,409)
Intangible assets, net	96,762	93,723
Covenants not-to-compete
Finite-Lived Intangible Assets [Line Items]
Intangible assets	30,193	28,777
Less accumulated amortization	(23,094)	(22,148)
Intangible assets, net	7,099	6,629
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Intangible assets	124,680	115,005
Less accumulated amortization	(40,296)	(34,809)
Intangible assets, net	84,384	80,196
Trade Names
Finite-Lived Intangible Assets [Line Items]
Intangible assets	8,350	8,350
Less accumulated amortization	(3,071)	(1,452)
Intangible assets, net	$ 5,279	$ 6,898

GOODWILL AND INTANGIBLE ASSET_4

GOODWILL AND INTANGIBLE ASSETS - Narrative (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible amortization expense	$ 4,262	$ 2,015	$ 8,052	$ 4,043

GOODWILL AND INTANGIBLE ASSET_5

GOODWILL AND INTANGIBLE ASSETS - Summary of Intangible Amortization Expense Estimated (Detail) $ in Thousands	Jun. 30, 2022 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Fiscal year ending December 31, 2022	$ 8,158
Fiscal year ending December 31, 2023	15,600
Fiscal year ending December 31, 2024	14,879
Fiscal year ending December 31, 2025	13,758
Fiscal year ending December 31, 2026	12,123
Thereafter	$ 32,244

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, 2022	Jun. 30, 2021
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	$ 86,914	$ 82,533
Obligations incurred	2,244	2,319
Revision in estimates	1,443	0
Accretion expense	3,799	3,676
Obligations settled	(2,027)	(2,969)
Ending balance	$ 92,373	$ 85,559

DEBT - Summary of Debt (Details

DEBT - Summary of Debt (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Weighted-average discount rate - finance leases	3.60%
Finance leases maturing through December 2107; bearing interest at a weighted average of 3.6%	$ 45,889	$ 45,724
Principal amount of debt	593,662	562,570
Less - unamortized debt issuance costs	10,470	10,166
Debt less unamortized debt issuance costs	583,192	552,404
Less—current maturities of debt	7,636	9,901
Debt, less current portion	575,556	542,503
Secured Debt | Term loan A facility ("Term Loan Facility") due December 2026; bearing interest at LIBOR plus 1.375%
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 LIBOR plus 1.375% | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	1.375%
Line of Credit | Revolving credit facility due December 2026 ("Revolving Credit Facility"); bearing interest at LIBOR plus 1.375%
Debt Instrument [Line Items]
Principal amount of debt	$ 0	0
Line of Credit | Revolving credit facility due December 2026 ("Revolving Credit Facility"); bearing interest at LIBOR plus 1.375% | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	1.375%
Credit Facility | Revolving Credit Facility and Term Loan Facility (collectively, the "Credit Facility")
Debt Instrument [Line Items]
Less - unamortized debt issuance costs	$ 5,306	5,884
Unsecured Debt | New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014 ("New York Bonds 2014R-1") due December 2044 - fixed rate interest period through 2029; bearing interest at 2.875%
Debt Instrument [Line Items]
Stated interest rate	2.875%
Principal amount of debt	$ 25,000	25,000
Less - unamortized debt issuance costs	$ 899	933
Unsecured Debt | New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014R-2 ("New York Bonds 2014R-2") due December 2044 - fixed rate interest period through 2026; bearing interest at 3.125%
Debt Instrument [Line Items]
Stated interest rate	3.125%
Principal amount of debt	$ 15,000	15,000
Less - unamortized debt issuance costs	$ 238	268
Unsecured Debt | New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2020 ("New York Bonds 2020") due September 2050 - fixed rate interest period through 2025; bearing interest at 2.750%
Debt Instrument [Line Items]
Stated interest rate	2.75%
Principal amount of debt	$ 40,000	40,000
Less - unamortized debt issuance costs	$ 1,194	1,283
Unsecured Debt | Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2005R-3 ("FAME Bonds 2005R-3") due January 2025 - fixed rate interest period through 2025; bearing interest at 5.25%
Debt Instrument [Line Items]
Stated interest rate	5.25%
Principal amount of debt	$ 25,000	25,000
Less - unamortized debt issuance costs	$ 219	262
Unsecured Debt | Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2015R-1 ("FAME Bonds 2015R-1") due August 2035 - fixed rate interest period through 2025; bearing interest at 5.125%
Debt Instrument [Line Items]
Stated interest rate	5.125%
Principal amount of debt	$ 15,000	15,000
Less - unamortized debt issuance costs	$ 378	413
Unsecured Debt | Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2015R-2 ("FAME Bonds 2015R-2") due August 2035 - fixed rate interest period through 2025; bearing interest at 4.375%
Debt Instrument [Line Items]
Stated interest rate	4.375%
Principal amount of debt	$ 15,000	15,000
Less - unamortized debt issuance costs	$ 231	268
Unsecured Debt | Vermont Economic Development Authority Solid Waste Disposal Long-Term Revenue Bonds Series 2013 ("Vermont Bonds 2013") due April 2036 - fixed rate interest period through 2028; bearing interest at 4.625%
Debt Instrument [Line Items]
Stated interest rate	4.625%
Principal amount of debt	$ 16,000	16,000
Less - unamortized debt issuance costs	$ 405	433
Unsecured Debt | Vermont Economic Development Authority Solid Waste Disposal Long-Term Revenue Bonds Series 2022A-1 ("Vermont Bonds 2022A-1") due June 2052 - fixed rate interest period through 2027; bearing interest at 5.00%
Debt Instrument [Line Items]
Stated interest rate	5%
Principal amount of debt	$ 35,000	0
Less - unamortized debt issuance costs	$ 1,207	0
Unsecured Debt | Business Finance Authority of the State of New Hampshire Solid Waste Disposal Revenue Bonds Series 2013 ("New Hampshire Bonds") due April 2029 - fixed rate interest period through 2029; bearing interest at 2.95%
Debt Instrument [Line Items]
Stated interest rate	2.95%
Principal amount of debt	$ 11,000	11,000
Less - unamortized debt issuance costs	$ 393	422
Notes payable maturing through August 2024; bearing interest at a weighted average of 1.6%
Debt Instrument [Line Items]
Weighted average interest rate	1.60%
Principal amount of debt	$ 773	$ 4,846

DEBT - Financing Activities and

DEBT - Financing Activities and Credit Facility Narrative (Details)	6 Months Ended
	Jun. 30, 2022 USD ($)
Debt Instrument [Line Items]
Additional borrowing capacity	$ 125,000,000
Line of Credit
Debt Instrument [Line Items]
Debt instrument, term (in years)	5 years
Net leverage ratio	2.25
Line of credit facility, remaining borrowing capacity	$ 271,805,000
Line of credit, amount drawn	$ 0
Line of Credit | LIBOR | Maximum
Debt Instrument [Line Items]
Floor interest rate received (as a percent)	1.375%
Line of Credit | LIBOR | Minimum
Debt Instrument [Line Items]
Floor interest rate received (as a percent)	1.125%
Vermont Economic Development Authority Solid Waste Disposal Long-Term Revenue Bonds Series 2022A-1 ("Vermont Bonds 2022A-1") due June 2052 - fixed rate interest period through 2027; bearing interest at 5.00% | Unsecured Debt
Debt Instrument [Line Items]
Aggregate principal amount	$ 35,000,000
Stated interest rate	5%
Restricted cash	$ 1,006,000
Term loan A facility ("Term Loan Facility") due December 2026; bearing interest at LIBOR plus 1.375% | Secured Debt
Debt Instrument [Line Items]
Aggregate principal amount	350,000,000
Revolving credit facility due December 2026 ("Revolving Credit Facility"); bearing interest at LIBOR plus 1.375% | Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Credit facility maximum	300,000,000
Letters of credit outstanding	28,195,000
Revolving credit facility due December 2026 ("Revolving Credit Facility"); bearing interest at LIBOR plus 1.375% | Revolving Credit Facility | Letter of Credit
Debt Instrument [Line Items]
Letters of credit sublimit	$ 75,000,000

DEBT - Cash Flow Hedges Narrati

DEBT - Cash Flow Hedges Narrative (Details) - Cash Flow Hedging - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Interest Rate Derivative
Debt Instrument [Line Items]
Notional amount	$ 190,000	$ 195,000
Floor interest rate (as a percent)	0%
Weighted average percentage rate paid (as a percent)	2.20%
Forward Starting Interest Rate Derivative
Debt Instrument [Line Items]
Notional amount	$ 20,000	$ 85,000
Floor interest rate (as a percent)	0%
Weighted average percentage rate paid (as a percent)	1.29%

DEBT - Summary of Cash Flow Hed

DEBT - Summary of Cash Flow Hedges (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Derivatives, Fair Value [Line Items]
Accumulated other comprehensive income (loss), net of tax	$ 4,020	$ (5,103)
Designated as Hedging Instrument | Interest rate swaps
Derivatives, Fair Value [Line Items]
Cash flow hedge derivatives, gross asset	6,962	424
Cash flow hedge derivatives, gross liability	0	5,176
Designated as Hedging Instrument | Interest rate swaps | Accumulated gain (loss), cash flow hedge
Derivatives, Fair Value [Line Items]
Accumulated other comprehensive income (loss), before tax	6,962	(4,935)
Accumulated other comprehensive income (loss), tax	(2,942)	(168)
Accumulated other comprehensive income (loss), net of tax	4,020	(5,103)
Other current assets | Designated as Hedging Instrument | Interest rate swaps
Derivatives, Fair Value [Line Items]
Cash flow hedge derivatives, gross asset	1,454	0
Other non-current assets | Designated as Hedging Instrument | Interest rate swaps
Derivatives, Fair Value [Line Items]
Cash flow hedge derivatives, gross asset	5,508	424
Other accrued liabilities | Designated as Hedging Instrument | Interest rate swaps
Derivatives, Fair Value [Line Items]
Cash flow hedge derivatives, gross liability	0	3,796
Other long-term liabilities | Designated as Hedging Instrument | Interest rate swaps
Derivatives, Fair Value [Line Items]
Cash flow hedge derivatives, gross liability	$ 0	$ 1,380

DEBT - Schedule of Loss On Cash

DEBT - Schedule of Loss On Cash Flow Hedges (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Other comprehensive loss, reclassification adjustment from AOCI	$ 994	$ 1,202	$ 2,122	$ 2,347
Interest rate swaps | Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Other comprehensive loss, reclassification adjustment from AOCI	$ 994	$ 1,202	$ 2,122	$ 2,347

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Narrative (Detail) $ in Thousands	Jun. 30, 2022 USD ($)
Loss Contingencies [Line Items]
Loss contingency accrual	$ 1,291
Minimum
Loss Contingencies [Line Items]
Risk free interest (as a percent)	1.50%
Maximum
Loss Contingencies [Line Items]
Risk free interest (as a percent)	2.60%

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES - Environmental Remediation Liability (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	$ 5,887	$ 5,200
Accretion expense	54	56
Obligations settled	(72)	(281)
Ending balance	5,869	4,975
Less: current portion	280	375
Long-term portion	$ 5,589	$ 4,600

STOCKHOLDERS' EQUITY - Narrativ

STOCKHOLDERS' EQUITY - Narrative (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation, weighted average period			2 years 1 month 6 days
Fair value of stock awards vested	$ 814,000		$ 5,359,000
Stock Options
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense	17,000	$ 0	33,000	$ 0
Unrecognized stock-based compensation expense, stock options	139,000		139,000
Aggregate intrinsic value of options exercised	1,156,000		1,467,000
Restricted Stock, Restricted Stock Units And Performance Stock Units
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense	828,000	3,044,000	2,979,000	5,928,000
Restricted Stock
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense	58,000		$ 58,000
Restricted Stock | Non Employee Director
Limited Partners' Capital Account [Line Items]
Options, vesting period (in years)			3 years
Restricted Stock Unit
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense	5,543,000		$ 5,543,000
Performance Stock Unit
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense	6,882,000		$ 6,882,000
Weighted average | Restricted Stock
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation, weighted average period			1 year 6 months
Weighted average | Restricted Stock Unit
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation, weighted average period			1 year 10 months 24 days
Weighted average | Performance Stock Unit
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation, weighted average period			1 year 9 months 18 days
2016 Plan
Limited Partners' Capital Account [Line Items]
Options granted, term (in years)			10 years
2016 Plan | Minimum
Limited Partners' Capital Account [Line Items]
Options, vesting period (in years)			1 year
2016 Plan | Maximum
Limited Partners' Capital Account [Line Items]
Options, vesting period (in years)			4 years
Amended and Restated 1997 Employee Stock Purchase Plan
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense	$ 93,000	$ 72,000	$ 166,000	$ 128,000
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)	868,000		868,000
Class A Common Stock | 2006 Incentive Plan
Limited Partners' Capital Account [Line Items]
Common stock, additional authorized shares (in shares)			2,723,000

STOCKHOLDERS' EQUITY - Summary

STOCKHOLDERS' EQUITY - Summary of Stock Option Activity (Detail) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended
	Jun. 30, 2022 USD ($) $ / shares shares
Stock Options
Beginning balance, outstanding (in shares) | shares	77
Granted (in shares) | shares	0
Exercised (in shares) | shares	(23)
Forfeited (in shares) | shares	0
Ending balance, outstanding (in shares) | shares	54
Exercisable at end of period (in shares) | shares	46
Weighted Average Exercise Price
Beginning balance, outstanding (in dollars per share) | $ / shares	$ 15.68
Granted (in dollars per share) | $ / shares	0
Exercised (in dollars per share) | $ / shares	8.56
Forfeited (in dollars per share) | $ / shares	0
Ending balance, outstanding (in dollars per share) | $ / shares	18.62
Exercisable at end of period (in dollars per share) | $ / shares	$ 9.49
Weighted Average Remaining Contractual Term (years) and Aggregate Intrinsic Value
Outstanding contractual term	4 years 3 months 18 days
Exercisable contractual term	3 years 6 months
Outstanding aggregate intrinsic value | $	$ 2,946
Exercisable aggregate intrinsic value | $	$ 2,913

STOCKHOLDERS' EQUITY - Summar_2

STOCKHOLDERS' EQUITY - Summary of Restricted Stock, Restricted Stock Unit and Performance-based Stock Unit Activity (Detail) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended
	Jun. 30, 2022 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)	184
Restricted Stock, Restricted Stock Units And Performance Stock Units
Restricted Stock, Restricted Stock Units, and Performance Stock Units
Outstanding, beginning of period (in shares)	249
Granted (in shares)	82
Forfeited (in shares)	(34)
Outstanding, end of period (in shares)	234
Weighted Average Grant Date Fair Value
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 55.40
Granted (in dollars per share) | $ / shares	94.31
Forfeited (in dollars per share) | $ / shares	67.73
Outstanding at end of period (in dollars per share) | $ / shares	$ 68.86
Weighted Average Remaining Contractual Term (years) and Aggregate Intrinsic Value
Contractual term (in years)	1 year 10 months 24 days
Aggregate intrinsic value | $	$ 17,031
Restricted Stock, Restricted Stock Units And Performance Stock Units | Class A Common Stock
Restricted Stock, Restricted Stock Units, and Performance Stock Units
Vested (in shares)	(63)
Weighted Average Grant Date Fair Value
Class A Common Stock Vested (in dollars per share) | $ / shares	$ 49
Unvested | Restricted Stock, Restricted Stock Units And Performance Stock Units
Restricted Stock, Restricted Stock Units, and Performance Stock Units
Outstanding, end of period (in shares)	418
Weighted Average Grant Date Fair Value
Outstanding at end of period (in dollars per share) | $ / shares	$ 68.97
Weighted Average Remaining Contractual Term (years) and Aggregate Intrinsic Value
Contractual term (in years)	1 year 7 months 6 days
Aggregate intrinsic value | $	$ 30,407

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, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 435,050	$ 422,457	$ 373,336	$ 362,142	$ 422,457	$ 362,142
Other comprehensive income (loss), net of tax	2,980	6,143	(235)	3,830	9,123	3,595
Ending balance	457,566	435,050	$ 388,492	$ 373,336	457,566	$ 388,492
Accumulated Gain (Loss), Cash Flow Hedge
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance		$ (5,103)			(5,103)
Other comprehensive income					9,774
Amounts reclassified from accumulated other comprehensive income (loss)					2,122
Income tax provision related to items of other comprehensive income					(2,773)
Other comprehensive income (loss), net of tax					9,123
Ending balance	$ 4,020				$ 4,020

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, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ 5,698		$ 5,296		$ 10,902	$ 10,764
Income before income taxes	26,375		17,226		31,523	23,969
Provision for income taxes	8,579		5,443		9,537	7,875
Net income	17,796	$ 4,190	11,783	$ 4,311	21,986	16,094
Accumulated Gain (Loss), Cash Flow Hedge | Amounts Reclassified Out of Accumulated Other Comprehensive Income (Loss), Net of Tax
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	(994)		(1,202)		(2,122)	(2,347)
Provision for income taxes	0		(142)		(190)	(269)
Net income	(994)		(1,060)		(1,932)	(2,078)
Interest rate swaps | Accumulated Gain (Loss), Cash Flow Hedge | Amounts Reclassified Out of Accumulated Other Comprehensive Income (Loss), Net of Tax
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ 994		$ 1,202		$ 2,122	$ 2,347

EARNINGS PER SHARE (Details)

EARNINGS PER SHARE (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Numerator:
Net income	$ 17,796	$ 11,783	$ 21,986	$ 16,094
Denominators:
Unvested restricted stock (in shares)	(2,000)	(2,000)	(2,000)	(2,000)
Effect of weighted average shares outstanding (in shares)	(34,000)	(18,000)	(109,000)	(111,000)
Weighted average common shares outstanding, basic (in shares)	51,642,000	51,366,000	51,567,000	51,273,000
Impact of potentially dilutive securities:
Dilutive effect of stock options and other stock awards (in shares)	139,000	180,000	153,000	193,000
Weighted average common shares outstanding, diluted	51,781,000	51,546,000	51,720,000	51,466,000
Anti-dilutive potentially issuable shares (in shares)	70,000	0	70,000	48,000
Class A Common Stock
Denominators:
Common stock, shares outstanding (in shares)	50,690,000	50,398,000	50,690,000	50,398,000	50,423,000
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, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Unusual or Infrequent Items, or Both [Abstract]
Expense from acquisition activities	$ 1,019	$ 1,632	$ 3,062	$ 2,046

FAIR VALUE OF FINANCIAL INSTR_3

FAIR VALUE OF FINANCIAL INSTRUMENTS - Recurring Fair Value Measurements (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Assets:
Restricted investment securities - landfill closure	$ 2,805	$ 2,122
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Interest rate swaps	0	0
Total assets	1,799	2,122
Liabilities:
Interest rate swaps		0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Landfill
Assets:
Restricted investment securities - landfill closure	1,799	2,122
Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Interest rate swaps	6,962	424
Total assets	6,962	424
Liabilities:
Interest rate swaps		5,176
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:
Interest rate swaps		0
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 ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Term loan A facility ("Term Loan Facility") due December 2026; bearing interest at LIBOR plus 1.375% | Secured Debt
Debt Instrument [Line Items]
Principal amount of debt	$ 350,000	$ 350,000
Fair Value | Fixed Rate Bonds
Debt Instrument [Line Items]
Fixed rate debt	189,558
Carrying Value
Debt Instrument [Line Items]
Revolving credit facility	0
Carrying Value | Fixed Rate Bonds
Debt Instrument [Line Items]
Fixed rate debt	$ 197,000

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, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Segment Reporting Information [Line Items]
Revenues	$ 283,666	$ 215,875	$ 517,693	$ 405,406
Depreciation and amortization	31,150	24,337	60,579	47,019
Operating income (loss)	31,719	21,946	41,887	33,955
Total assets	1,370,719	1,227,833	1,370,719	1,227,833	$ 1,283,580
Operating | Eastern
Segment Reporting Information [Line Items]
Revenues	87,263	61,058	158,582	113,403
Depreciation and amortization	11,538	7,313	22,988	13,935
Operating income (loss)	6,150	3,781	3,920	6,027
Total assets	362,942	226,157	362,942	226,157
Operating | Western
Segment Reporting Information [Line Items]
Revenues	114,884	98,852	210,723	184,616
Depreciation and amortization	15,939	15,089	30,598	29,128
Operating income (loss)	19,897	14,900	29,160	22,657
Total assets	697,252	654,314	697,252	654,314
Operating | Resource Solutions
Segment Reporting Information [Line Items]
Revenues	81,519	55,965	148,388	107,387
Depreciation and amortization	3,110	1,548	5,872	3,116
Operating income (loss)	6,235	3,651	9,928	6,113
Total assets	189,820	95,664	189,820	95,664
Corporate entities
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Depreciation and amortization	563	387	1,121	840
Operating income (loss)	(563)	(386)	(1,121)	(842)
Total assets	120,705	251,698	120,705	251,698
Inter-company revenues
Segment Reporting Information [Line Items]
Revenues	(61,955)	(50,971)	(111,893)	(93,982)
Inter-company revenues | Eastern
Segment Reporting Information [Line Items]
Revenues	(22,147)	(16,128)	(38,815)	(28,554)
Inter-company revenues | Western
Segment Reporting Information [Line Items]
Revenues	(39,491)	(33,566)	(71,983)	(62,248)
Inter-company revenues | Resource Solutions
Segment Reporting Information [Line Items]
Revenues	$ (317)	$ (1,277)	$ (1,095)	$ (3,180)

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, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenue from External Customer [Line Items]
Revenues	$ 283,666	$ 215,875	$ 517,693	$ 405,406
Solid waste operations
Revenue from External Customer [Line Items]
Revenues	202,147	159,910	369,305	298,019
Collection
Revenue from External Customer [Line Items]
Revenues	137,261	107,327	256,793	204,796
Disposal
Revenue from External Customer [Line Items]
Revenues	60,204	49,173	103,356	87,026
Power generation
Revenue from External Customer [Line Items]
Revenues	1,753	1,100	4,407	2,403
Processing
Revenue from External Customer [Line Items]
Revenues	2,929	2,310	4,749	3,794
Resource Solutions operations
Revenue from External Customer [Line Items]
Revenues	81,519	55,965	148,388	107,387
Processing
Revenue from External Customer [Line Items]
Revenues	33,867	21,031	61,263	38,302
Non-processing
Revenue from External Customer [Line Items]
Revenues	$ 47,652	$ 34,934	$ 87,125	$ 69,085