CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
OPERATING ACTIVITIES
Net income	$ 260,872	$ 148,033
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	95,169	88,113
Amortization of intangibles	9,691	2,882
Share-based compensation expense	9,816	8,567
Provision for losses on accounts receivable	5,065	(57)
Change in deferred income taxes	3,745	(8,593)
Gain on sale of property and equipment	(9,759)	(8,389)
Gain on sale of subsidiary	(402)	(6,923)
Changes in operating assets and liabilities:
Receivables	(54,889)	(103,886)
Prepaid expenses	7,550	7,655
Other assets	287	539
Income taxes	(11,068)	8,174
Operating right-of-use assets and lease liabilities, net	1,579	650
Accounts payable, accrued expenses, and other liabilities	32,793	101,577
NET CASH PROVIDED BY OPERATING ACTIVITIES	350,449	238,342
INVESTING ACTIVITIES
Purchases of property, plant and equipment, net of financings	(76,068)	(43,506)
Proceeds from sale of property and equipment	13,938	11,509
Proceeds from sale of subsidiary	475	9,013
Purchases of short-term investments	(145,254)	(56,011)
Proceeds from sale of short-term investments	48,161	61,174
Capitalization of internally developed software	(13,922)	(14,308)
Business acquisition, net of cash acquired	2,279
NET CASH USED IN INVESTING ACTIVITIES	(170,391)	(32,129)
FINANCING ACTIVITIES
Borrowings under credit facilities	58,000
Proceeds from notes payable	12,113
Payments on long-term debt	(99,567)	(76,513)
Net change in book overdrafts	2,102	(305)
Deferred financing costs	(53)	(295)
Payment of common stock dividends	(7,892)	(6,145)
Purchases of treasury stock	(50,117)	(8,100)
Payments for tax withheld on share-based compensation	(15,733)	(10,602)
NET CASH USED IN FINANCING ACTIVITIES	(101,147)	(101,960)
NET INCREASE IN CASH AND CASH EQUIVALENTS	78,911	104,253
Cash and cash equivalents at beginning of period	76,620	303,954
CASH AND CASH EQUIVALENTS AT END OF PERIOD	155,531	408,207
NONCASH INVESTING ACTIVITIES
Equipment financed	57,241	36,731
Accruals for equipment received	5,587	3,158
Lease liabilities arising from obtaining right-of-use assets	$ 78,324	$ 7,280