CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 512,371	$ 444,698
Short-term marketable securities	82,371	106,101
Accounts receivable, net of allowances aggregating $48,570 and $42,209, respectively	1,100,660	983,111
Unbilled accounts receivable	204,308	107,859
Inventories and supplies	376,564	327,511
Prepaid expenses and other current assets	78,204	82,939
Total current assets	2,354,478	2,052,219
Property, plant and equipment, net	2,452,312	2,193,318
Other assets:
Operating lease right-of-use assets	246,061	187,060
Goodwill	1,485,065	1,287,736
Permits and other intangibles, net	708,935	602,797
Other long-term assets	59,159	59,739
Total other assets	2,499,220	2,137,332
Total assets	7,306,010	6,382,869
Current liabilities:
Current portion of long-term debt	15,102	10,000
Accounts payable	504,206	451,806
Deferred revenue	103,291	95,230
Accrued expenses and other current liabilities	398,236	397,157
Current portion of closure, post-closure and remedial liabilities	30,477	26,914
Current portion of operating lease liabilities	70,539	56,430
Total current liabilities	1,121,851	1,037,537
Other liabilities:
Closure and post-closure liabilities, less current portion of $14,203 and $13,556, respectively	105,375	105,044
Remedial liabilities, less current portion of $16,274 and $13,358, respectively	94,384	97,885
Long-term debt, less current portion	2,773,659	2,291,717
Operating lease liabilities, less current portion	179,040	131,743
Deferred tax liabilities	356,150	353,107
Other long-term liabilities	147,241	118,330
Total other liabilities	3,655,849	3,097,826
Commitments and contingent liabilities (See Note 15)
Stockholders’ equity:
Authorized 80,000,000 shares; issued and outstanding 53,898,805 and 53,929,703 shares, respectively	539	539
Additional paid-in capital	438,904	459,728
Accumulated other comprehensive loss	(192,036)	(175,339)
Retained earnings	2,280,903	1,962,578
Total stockholders’ equity	2,528,310	2,247,506
Total liabilities and stockholders’ equity	$ 7,306,010	$ 6,382,869