CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net income	$ 356,948,000	$ 171,474,000	$ 73,559,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	153,726,000	130,629,000	123,679,000
Impairment of right-of-use asset	5,874,000	0	0
Deferred taxes	4,448,000	(3,992,000)	7,463,000
Compensation expense related to share-based compensation plans	20,426,000	20,056,000	17,053,000
(Gain) loss on sale of assets	(24,176,000)	(19,173,000)	907,000
Other operating activities	0	0	6,385,000
Changes in operating assets and liabilities, net of acquisitions:
Restricted investments	6,191,000	(903,000)	(752,000)
Accounts receivable, net	8,298,000	(115,568,000)	(47,219,000)
Prepaid taxes	(14,796,000)	(856,000)	(707,000)
Prepaid expenses and other current assets	(3,111,000)	(647,000)	(2,508,000)
Other assets	(4,231,000)	(2,883,000)	(2,177,000)
Accounts payable	(89,103,000)	78,448,000	5,594,000
Accrued expenses	57,613,000	9,686,000	(4,408,000)
Non-current liabilities	(19,944,000)	(13,436,000)	(1,915,000)
Net cash provided by operating activities	458,163,000	252,835,000	174,954,000
Cash flows from investing activities:
Proceeds from sale of equipment	42,929,000	45,177,000	3,289,000
Purchases of property and equipment	(219,140,000)	(132,952,000)	(115,306,000)
Acquisitions, net of cash acquired	(102,661,000)	(122,360,000)	(84,845,000)
Net cash used in investing activities	(278,872,000)	(210,135,000)	(196,862,000)
Cash flows from financing activities:
Proceeds from issuance of debt	179,195,000	112,001,000	187,475,000
Repayments of long-term debt	(111,482,000)	(107,608,000)	(198,741,000)
Purchase of treasury stock	(75,000,000)	0	0
Purchase of treasury stock from related party (Note 17)	(34,767,000)	0	0
Stock tendered for payments of withholding taxes	(8,312,000)	(9,123,000)	(7,963,000)
Finance lease payments	(2,093,000)	(2,682,000)	(3,066,000)
Net cash used in financing activities	(52,459,000)	(7,412,000)	(22,295,000)
Effect of exchange rate changes on cash and cash equivalents	26,000	(10,000)	(20,000)
Net increase (decrease) in cash and cash equivalents	126,858,000	35,278,000	(44,223,000)
Cash and cash equivalents beginning of the year	159,784,000	124,506,000	168,729,000
Cash and cash equivalents end of the year	286,642,000	159,784,000	124,506,000
Supplemental disclosures of cash paid for:
Interest	7,991,000	7,602,000	9,458,000
Income taxes	$ 128,812,000	$ 58,593,000	$ 18,388,000