CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash Flows from Operating Activities:
Net income	$ 31,955	$ 28,189
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	74,510	67,281
Interest accretion on landfill and environmental remediation liabilities	5,915	5,324
Amortization of debt issuance costs	1,716	1,597
Stock-based compensation	8,712	5,345
Operating lease right-of-use assets expense	9,981	12,347
(Gain) loss on sale of property and equipment	(1)	254
Southbridge Landfill non-cash closure charge	112	2,077
Non-cash expense from acquisition activities	532	549
Deferred income taxes	12,974	1,514
Changes in assets and liabilities, net of effects of acquisitions and divestitures:
Accounts receivable	(10,943)	6,400
Landfill operating lease contract expenditures	(3,646)	(3,386)
Accounts payable	20,318	(8,585)
Prepaid expenses, inventories and other assets	(14,391)	(2,908)
Accrued expenses, contract liabilities and other liabilities	(3,655)	(4,083)
Net cash provided by operating activities	134,089	111,915
Cash Flows from Investing Activities:
Acquisitions, net of cash acquired	(153,112)	(25,379)
Additions to property, plant and equipment	(81,577)	(77,271)
Proceeds from sale of property and equipment	593	430
Net cash used in investing activities	(234,096)	(102,220)
Cash Flows from Financing Activities:
Proceeds from debt borrowings	500	154,400
Principal payments on debt	(8,517)	(145,008)
Payments of debt issuance costs	0	(1,531)
Proceeds from the exercise of share based awards	163	100
Net cash (used in) provided by financing activities	(7,854)	7,961
Net (decrease) increase in cash and cash equivalents	(107,861)	17,656
Cash and cash equivalents, beginning of period	154,342	3,471
Cash and cash equivalents, end of period	46,481	21,127
Supplemental Disclosure of Cash Flow Information:
Cash interest payments	14,378	15,239
Cash income tax payments	597	(1,650)
Non-current assets obtained through long-term financing obligations	18,153	16,937
Right-of-use assets obtained in exchange for operating lease liabilities	$ 3,566	$ 3,289