CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Cash flows from operating activities:
Net income	$ 35,534	$ 55,035
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	74,313	67,229
Deferred income taxes	(111)	(254)
Gain on disposal of property and equipment	(18,339)	(20,458)
Non-cash equity compensation	3,403	3,026
Insurance and claims accruals, net of current portion	954	4,470
Loss on investments in equity securities	81	9,806
Other	(417)	(2,080)
Changes in certain working capital items:
Accounts receivable, net	57,866	11,279
Other current assets	17,336	13,152
Accounts payable	6,484	12,330
Other current liabilities	(10,257)	1,422
Net cash provided by operating activities	166,847	154,957
Cash flows from investing activities:
Additions to property and equipment	(161,764)	(73,629)
Proceeds from sales of property and equipment	59,021	36,555
Net cash invested in acquisition	(188)	705
Payment to acquire equity method investment	(2,125)	0
Issuance of notes receivable	(25,000)	0
Decrease in notes receivable	826	1,831
Net cash used in investing activities	(129,230)	(34,538)
Cash flows from financing activities:
Repayments of short-term debt	(2,500)	(1,250)
Repayments of long-term debt	0	(100,000)
Proceeds from issuance of long-term debt	0	100,000
Dividends on common stock	(8,220)	(7,895)
Repurchases of common stock	0	(36,180)
Tax withholding related to net share settlements of restricted stock awards	(5,514)	(3,658)
Net cash used in financing activities	(16,234)	(48,983)
Effect of exchange rate fluctuations on cash	968	317
Net increase in cash and cash equivalents	22,351	71,753
Cash and cash equivalents, beginning of period	107,240	54,196
Cash and cash equivalents, end of period	129,591	125,949
Supplemental disclosures of cash flow information:
Interest paid	8,244	1,536
Income taxes paid	219	837
Supplemental schedule of non-cash investing and financing activities:
Notes receivable issued upon sale of property and equipment	756	1,613
Change in fair value of interest rate swaps	(973)	3,631
Property and equipment acquired included in accounts payable	4,008	13,671
Property and equipment disposed included in other receivables	110	154
Dividends accrued but not yet paid at end of period	8,239	7,807
Contingent consideration associated with acquisitions	$ (800)	$ 0