CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
CURRENT ASSETS:
Cash and cash equivalents	$ 46,481	$ 154,342
Accounts receivable, net of allowance for credit losses of $3,057 and $2,333, respectively	90,500	74,198
Refundable income taxes	0	229
Prepaid expenses	16,806	9,289
Inventory	9,797	7,868
Other current assets	3,575	1,328
Total current assets	167,159	247,254
Property, plant and equipment, net of accumulated depreciation and amortization of $952,032 and $900,882, respectively	617,348	510,512
Operating lease right-of-use assets	96,712	95,310
Goodwill	227,929	194,901
Intangible assets, net	92,908	58,324
Restricted assets	1,948	1,848
Cost method investments	11,264	11,264
Deferred income taxes	46,777	61,163
Other non-current assets	18,352	13,322
Total assets	1,280,397	1,193,898
CURRENT LIABILITIES:
Current maturities of debt	16,751	9,240
Current operating lease liabilities	7,128	8,547
Accounts payable	69,516	49,198
Accrued payroll and related expenses	19,793	17,282
Accrued interest	1,960	2,126
Contract liabilities	3,422	2,685
Current accrued capping, closure and post-closure costs	17,848	10,268
Other accrued liabilities	41,951	31,862
Total current liabilities	178,369	131,208
Debt, less current portion	534,752	530,411
Operating lease liabilities, less current portion	59,001	60,979
Accrued capping, closure and post-closure costs, less current portion	68,425	72,265
Deferred income taxes	879	912
Other long-term liabilities	31,020	35,981
COMMITMENTS AND CONTINGENCIES
STOCKHOLDERS' EQUITY:
Additional paid-in capital	648,611	639,247
Accumulated deficit	(234,144)	(266,099)
Accumulated other comprehensive loss, net of tax	(7,030)	(11,517)
Total stockholders' equity	407,951	362,142
Total liabilities and stockholders' equity	1,280,397	1,193,898
Class A Common Stock
STOCKHOLDERS' EQUITY:
Common stock	504	501
Class B Common Stock
STOCKHOLDERS' EQUITY:
Common stock	$ 10	$ 10