CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 444,698	$ 492,603
Short-term marketable securities	106,101	62,033
Accounts receivable, net of allowances aggregating $42,209 and $45,253, respectively	983,111	964,603
Unbilled accounts receivable	107,859	107,010
Inventories and supplies	327,511	324,994
Prepaid expenses and other current assets	82,939	82,518
Total current assets	2,052,219	2,033,761
Property, plant and equipment, net	2,193,318	1,980,302
Other assets:
Operating lease right-of-use assets	187,060	166,181
Goodwill	1,287,736	1,246,878
Permits and other intangibles, net	602,797	620,782
Other long-term assets	59,739	81,803
Total other assets	2,137,332	2,115,644
Total assets	6,382,869	6,129,707
Current liabilities:
Current portion of long-term debt	10,000	10,000
Accounts payable	451,806	446,629
Deferred revenue	95,230	94,094
Accrued expenses and other current liabilities	397,157	396,716
Current portion of closure, post-closure and remedial liabilities	26,914	23,123
Current portion of operating lease liabilities	56,430	49,532
Total current liabilities	1,037,537	1,020,094
Other liabilities:
Closure and post-closure liabilities, less current portion of $13,556 and $13,205, respectively	105,044	105,596
Remedial liabilities, less current portion of $13,358 and $9,918, respectively	97,885	106,372
Long-term debt, less current portion	2,291,717	2,414,828
Operating lease liabilities, less current portion	131,743	119,259
Deferred tax liabilities	353,107	350,389
Other long-term liabilities	118,330	90,847
Total other liabilities	3,097,826	3,187,291
Commitments and contingent liabilities (See Note 18)
Stockholders' equity:
Common stock	539	541
Additional paid-in capital	459,728	504,240
Accumulated other comprehensive loss	(175,339)	(167,181)
Retained earnings	1,962,578	1,584,722
Total stockholders' equity	2,247,506	1,922,322
Total liabilities and stockholders' equity	$ 6,382,869	$ 6,129,707