Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Cash flows from operating activities:
Net income	$ 184,569	$ 183,613
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	206,097	196,431
Deferred income taxes	10,262	14,756
Gain on disposal of property and equipment	(62,659)	(39,292)
Non-cash equity compensation	9,120	7,999
Insurance and claims accruals, net of current portion	1,469	2,362
Other	(5,056)	(1,422)
Gain on investments in equity securities, net	(14,403)	(36,281)
Changes in certain working capital items:
Accounts receivable, net	(32,258)	(69,072)
Other current assets	3,922	(10,319)
Accounts payable	21,061	17,236
Other current liabilities	10,592	(12,667)
Net cash provided by operating activities	332,716	253,344
Cash flows from investing activities:
Additions to property and equipment	(379,902)	(295,485)
Proceeds from sales of property and equipment	125,830	132,755
Net cash invested in acquisition	705	(141,291)
Investment in equity securities	(20,250)	(10,000)
Decrease in notes receivable	4,870	5,114
Net cash used in investing activities	(268,747)	(308,907)
Cash flows from financing activities:
Repayments of short-term debt	(3,750)	(25,000)
Proceeds from issuance of short-term debt	0	5,000
Repayments of long-term debt	(100,000)	0
Proceeds from issuance of long-term debt	250,000	170,000
Dividends on common stock	(23,946)	(21,057)
Repurchases of common stock	(110,400)	(53,266)
Tax withholding related to net share settlements of restricted stock awards	(3,704)	(3,773)
Other cash flows from financing activities	(750)	(35)
Net cash provided by financing activities	7,450	71,869
Effect of exchange rate fluctuations on cash	68	(212)
Net increase in cash and cash equivalents	71,487	16,094
Cash and cash equivalents, beginning of period	54,196	29,334
Cash and cash equivalents, end of period	125,683	45,428
Supplemental disclosures of cash flow information:
Interest paid	5,664	2,517
Income taxes paid	38,797	56,350
Supplemental schedule of non-cash investing and financing activities:
Notes receivable issued upon sale of property and equipment	3,771	4,252
Change in fair value of interest rate swaps	6,772	2,063
Property and equipment acquired included in accounts payable	7,143	3,666
Property and equipment disposed included in other receivables	190	0
Dividends accrued but not yet paid at end of period	8,216	8,026
Redeemable noncontrolling interest associated with acquisition	$ 0	$ 35,322