Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Cash Flows from Operating Activities:
Net income	$ 1,163,109	$ 719,307	$ 656,982
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation & amortization	584,831	568,041	581,861
(Gain) loss on sales of assets and businesses	(9,920)	(6,250)	584
Stock-based compensation expense	99,349	87,720	85,378
Costs related to extinguishment of debt	3,158	0	0
Provision for asset impairment	0	0	57,550
Changes in assets & liabilities, net of effects from acquisitions and dispositions:
Accounts receivable	67,355	(182,444)	(258,338)
Accrued interest	12,814	1,193	1,835
Accrued and deferred income taxes	12,651	(43,450)	(29,510)
Other working capital accounts	61,897	(32,321)	(146,692)
Deferred grant revenue	0	2,978	2,391
Other assets and deferred charges	(12,163)	48,517	19,918
Other	21,811	39,133	(8,676)
Accrued insurance expense, net of commercial premiums paid	254,394	183,462	174,723
Payments made in settlement of self-insurance claims	(192,185)	(118,089)	(141,983)
Net cash provided by operating activities	2,067,101	1,267,797	996,023
Cash Flows from Investing Activities:
Property and equipment additions	(943,810)	(743,055)	(734,001)
Acquisition of businesses and property	(18,998)	(3,728)	(20,309)
Inflows (outflows) from foreign exchange contracts that hedge our net U.K. investment	12,860	(40,695)	94,913
Proceeds received from sales of assets and businesses	38,563	24,187	12,001
Decrease in capital reserves of commercial insurance subsidiary	276	16	100
Net cash used in investing activities	(911,109)	(763,275)	(647,296)
Cash Flows from Financing Activities:
Repayments of long-term debt	(2,640,001)	(85,480)	(89,367)
Additional borrowings	2,210,248	185,100	705,321
Financing costs	(12,566)	(308)	(3,164)
Repurchase of common shares	(670,754)	(547,363)	(832,918)
Dividends paid	(53,346)	(55,480)	(58,449)
Issuance of common stock	15,070	13,654	14,068
Profit distributions to noncontrolling interests	(6,508)	(6,830)	(5,391)
Purchase (sale) of ownership interests by (from) minority member	12,980	2,762	(48,500)
Net cash used in financing activities	(1,144,877)	(493,945)	(318,400)
Effect of exchange rate changes on cash and cash equivalents	(833)	3,056	(8,424)
Increase in cash, cash equivalents and restricted cash	10,282	13,633	21,903
Cash, cash equivalents and restricted cash, beginning of period	214,470	200,837	178,934
Cash, cash equivalents and restricted cash, end of period	224,752	214,470	200,837
Supplemental Disclosures of Cash Flow Information:
Interest paid	168,274	200,446	120,136
Income taxes paid, net of refunds	325,430	257,896	250,759
Noncash purchases of property and equipment	$ 118,109	$ 66,899	$ 72,064