Condensed Consolidated Statements of Earnings (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Operating revenues, excluding fuel surcharge revenues	$ 3,229,588	$ 3,488,588
Operating expenses:
Rents and purchased transportation	1,467,798	1,837,340
Salaries, wages and employee benefits	824,999	763,591
Fuel and fuel taxes	195,834	189,466
Depreciation and amortization	175,812	148,763
Operating supplies and expenses	128,360	106,939
Insurance and claims	70,328	46,131
General and administrative expenses, net of asset dispositions	60,404	37,447
Operating taxes and licenses	18,108	15,749
Communication and utilities	10,456	8,868
Total operating expenses	2,952,099	3,154,294
Operating income	277,489	334,294
Net interest expense	14,789	12,586
Earnings before income taxes	262,700	321,708
Income taxes	64,932	78,383
Net earnings	$ 197,768	$ 243,325
Weighted average basic shares outstanding (in shares)	103,724	104,894
Basic earnings per share (in dollars per share)	$ 1.91	$ 2.32
Weighted average diluted shares outstanding (in shares)	104,729	106,075
Diluted earnings per share (in dollars per share)	$ 1.89	$ 2.29
Service Excluding Fuel Surcharge [Member]
Operating revenues, excluding fuel surcharge revenues	$ 2,731,453	$ 3,042,217
Fuel Surcharge [Member]
Operating revenues, excluding fuel surcharge revenues	$ 498,135	$ 446,371