Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flows from operating activities:
Net income	$ 226,356	$ 157,938
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	136,377	121,371
Stock-based compensation	9,223	9,464
Amortization included in interest expense	2,950	2,962
Gain on disposition of assets	(1,937)	(1,896)
Loss on extinguishment of debt	0	21,604
Equity in earnings of investee	(1,101)	0
Deferred tax expense	1,212	1,743
Provision for doubtful accounts	4,368	1,246
Increase in:
Receivables	(36,153)	(17,626)
Prepaid expenses	(5,513)	(3,222)
Other assets	(2,581)	(569)
(Decrease) increase in:
Trade accounts payable	(995)	(1,212)
Accrued expenses	(15,086)	(9,182)
Operating lease liabilities	(21,780)	(29,039)
Other liabilities	17,290	31,675
Net cash provided by (used in) operating activities	312,630	285,257
Cash flows from investing activities:
Acquisitions	(234,292)	(27,236)
Capital expenditures	(75,802)	(41,416)
Proceeds from disposition of assets and investments	1,716	3,982
Net cash (used in) provided by investing activities	(308,378)	(64,670)
Cash flows from financing activities:
Cash used for purchase of treasury stock	(10,446)	(5,717)
Net proceeds from issuance of common stock	7,901	12,039
Principal payments on long-term debt	(182)	(190)
Principal payments on financing leases	(666)	(666)
Payments on revolving credit facility	(240,000)	(25,000)
Proceeds received from revolving credit facility	400,000	25,000
Redemption of senior notes	0	(668,688)
Proceeds received from note offering	0	550,000
Proceeds received from accounts receivable securitization program	65,000	32,500
Payments on accounts receivable securitization program	0	(32,500)
Debt issuance costs	(200)	(8,498)
Distributions to non-controlling interest	(98)	(49)
Dividends/distributions	(233,592)	(151,874)
Net cash used in financing activities	(12,283)	(273,643)
Effect of exchange rate changes in cash and cash equivalents	(71)	213
Net decrease in cash and cash equivalents	(8,102)	(52,843)
Cash and cash equivalents at beginning of period	99,788	121,569
Cash and cash equivalents at end of period	91,686	68,726
Supplemental disclosures of cash flow information:
Cash paid for interest	53,149	62,966
Cash paid for foreign, state and federal income taxes	$ 6,201	$ 4,886