CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 304,307	$ 492,603
Short-term marketable securities	71,818	62,033
Accounts receivable, net of allowances aggregating $43,850 and $45,253, respectively	963,659	964,603
Unbilled accounts receivable	137,507	107,010
Inventories and supplies	322,386	324,994
Prepaid expenses and other current assets	103,370	82,518
Total current assets	1,903,047	2,033,761
Property, plant and equipment, net	2,027,513	1,980,302
Other assets:
Operating lease right-of-use assets	167,144	166,181
Goodwill	1,287,416	1,246,878
Permits and other intangibles, net	636,523	620,782
Other	62,365	81,803
Total other assets	2,153,448	2,115,644
Total assets	6,084,008	6,129,707
Current liabilities:
Current portion of long-term debt	10,000	10,000
Accounts payable	427,480	446,629
Deferred revenue	101,336	94,094
Accrued expenses and other current liabilities	313,916	396,716
Current portion of closure, post-closure and remedial liabilities	22,780	23,123
Current portion of operating lease liabilities	51,325	49,532
Total current liabilities	926,837	1,020,094
Other liabilities:
Closure and post-closure liabilities, less current portion of $12,239 and $13,205, respectively	109,372	105,596
Remedial liabilities, less current portion of $10,541 and $9,918, respectively	103,800	106,372
Long-term debt, less current portion	2,409,654	2,414,828
Operating lease liabilities, less current portion	118,074	119,259
Deferred tax liabilities	344,333	350,389
Other long-term liabilities	91,894	90,847
Total other liabilities	3,177,127	3,187,291
Commitments and contingent liabilities (See Note 15)
Stockholders’ equity:
Common stock	541	541
Additional paid-in capital	503,907	504,240
Accumulated other comprehensive loss	(181,527)	(167,181)
Accumulated earnings	1,657,123	1,584,722
Total stockholders’ equity	1,980,044	1,922,322
Total liabilities and stockholders’ equity	$ 6,084,008	$ 6,129,707