Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Cash flows from operating activities:
Net earnings	$ 197,768	$ 243,325
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	175,812	148,763
Noncash lease expense	22,852	18,461
Share-based compensation	19,248	19,141
(Gain)/loss on sale of revenue equipment and other	6,038	(17,262)
Deferred income taxes	1,446	8,285
Changes in operating assets and liabilities:
Trade accounts receivable	145,179	(232,920)
Other assets	52,886	35,734
Trade accounts payable	(76,106)	86,959
Income taxes payable or receivable	52,951	33,688
Claims accruals	17,085	13,357
Accrued payroll and other accrued expenses	(127,538)	(65,746)
Net cash provided by operating activities	487,621	291,785
Cash flows from investing activities:
Additions to property and equipment	(461,314)	(309,338)
Net proceeds from sale of equipment	81,483	20,212
Business acquisition	0	(86,939)
Net cash used in investing activities	(379,831)	(376,065)
Cash flows from financing activities:
Proceeds from revolving lines of credit and other	945,400	0
Payments on revolving lines of credit and other	(966,100)	0
Purchase of treasury stock	(30,849)	(75,018)
Stock repurchased for payroll taxes and other	(11,980)	(9,782)
Dividends paid	(43,584)	(41,940)
Net cash used in financing activities	(107,113)	(126,740)
Net change in cash and cash equivalents	677	(211,020)
Cash and cash equivalents at beginning of period	51,927	355,549
Cash and cash equivalents at end of period	52,604	144,529
Supplemental disclosure of cash flow information:
Interest	24,577	20,974
Income taxes	7,455	22,153
Noncash investing activities
Accruals for equipment received	$ 134,578	$ 52,195