Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Cash flows from operating activities:
Net income	$ 207,086	$ 226,356
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	148,283	136,377
Stock-based compensation	12,446	9,223
Amortization included in interest expense	3,294	2,950
Gain on disposition of assets	(4,364)	(1,937)
Equity in earnings of investee	(627)	(1,101)
Deferred tax (benefit) expense	(345)	1,212
Provision for doubtful accounts	5,558	4,368
Increase in:
Receivables	(42,589)	(36,153)
Prepaid expenses	(5,453)	(5,513)
Other assets	(4,249)	(2,581)
(Decrease) increase in:
Trade accounts payable	(1,882)	(995)
Accrued expenses	(16,531)	(15,086)
Operating lease liabilities	(30,656)	(21,780)
Other liabilities	36,902	17,290
Net cash provided by (used in) operating activities	306,873	312,630
Cash flows from investing activities:
Acquisitions	(42,122)	(234,292)
Capital expenditures	(93,007)	(75,802)
Proceeds from disposition of assets and investments	5,120	1,716
Net cash (used in) provided by investing activities	(130,009)	(308,378)
Cash flows from financing activities:
Cash used for purchase of treasury stock	(5,946)	(10,446)
Net proceeds from issuance of common stock	7,692	7,901
Principal payments on long-term debt	(188)	(182)
Principal payments on financing leases	(666)	(666)
Payments on revolving credit facility	(110,000)	(240,000)
Proceeds received from revolving credit facility	198,000	400,000
Proceeds received from accounts receivable securitization program	31,900	65,000
Payments on accounts receivable securitization program	(47,000)	0
Debt issuance costs	(25)	(200)
Distributions to non-controlling interest	(367)	(98)
Dividends/distributions	(255,180)	(233,592)
Net cash used in financing activities	(181,780)	(12,283)
Effect of exchange rate changes in cash and cash equivalents	76	(71)
Net decrease in cash and cash equivalents	(4,840)	(8,102)
Cash and cash equivalents at beginning of period	52,619	99,788
Cash and cash equivalents at end of period	47,779	91,686
Supplemental disclosures of cash flow information:
Cash paid for interest	81,882	53,149
Cash paid for foreign, state and federal income taxes	$ 6,896	$ 6,201