Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Cash flows from operating activities:
Net earnings	$ 598,282	$ 570,886	$ 728,287
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	714,785	761,141	737,954
Noncash lease expense	96,007	100,178	97,666
Share-based compensation	71,753	65,686	79,189
Loss on sale of revenue equipment and other	13,739	14,557	27,806
Deferred income taxes	12,056	(89,848)	65,566
Changes in operating assets and liabilities:
Trade accounts receivable	63,796	110,746	259,449
Income taxes receivable or payable	81,854	(26,182)	12,165
Other current assets	17,684	94,639	(39,351)
Trade accounts payable	59,416	(109,806)	(48,346)
Claims accruals	61,074	48,137	18,429
Accrued payroll and other accrued expenses	(112,174)	(56,978)	(194,196)
Net cash provided by operating activities	1,678,272	1,483,156	1,744,618
Cash flows from investing activities:
Additions to property and equipment	(730,687)	(865,373)	(1,862,431)
Proceeds from sale of equipment	155,913	190,967	262,216
Proceeds from sale of investment	0	6,929	0
Business acquisitions	0	3,785	(85,000)
Net cash used in investing activities	(574,774)	(663,692)	(1,685,215)
Cash flows from financing activities:
Proceeds from long-term debt	750,000	0	0
Payments on long-term debt	(500,000)	(250,000)	0
Proceeds from revolving lines of credit and other	2,476,800	3,070,600	2,223,600
Payments on revolving lines of credit and other	(2,740,542)	(2,920,600)	(1,911,100)
Purchase of treasury stock	(923,292)	(513,924)	(159,576)
Stock repurchased for payroll taxes and other	(25,115)	(36,358)	(37,012)
Dividends paid	(171,048)	(175,543)	(173,898)
Net cash used in financing activities	(1,133,197)	(825,825)	(57,986)
Net (decrease)/increase in cash and cash equivalents	(29,699)	(6,361)	1,417
Cash and cash equivalents at beginning of year	46,983	53,344	51,927
Cash and cash equivalents at end of year	17,284	46,983	53,344
Supplemental disclosure of cash flow information:
Interest	66,561	80,861	65,561
Income taxes	123,504	305,103	135,385
Noncash investing activities
Accruals for equipment received	$ 24,170	$ 73,906	$ 44,692