Condensed Consolidated Statements of Earnings (Unaudited) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2025	Mar. 31, 2024
Operating revenues		$ 2,921,392	$ 2,944,001
Operating expenses:
Rents and purchased transportation		1,293,328	1,280,987
Salaries, wages and employee benefits		799,648	807,884
Depreciation and amortization		179,476	182,996
Fuel and fuel taxes		159,933	173,527
Operating supplies and expenses		123,452	122,991
Insurance and claims		85,017	75,686
General and administrative expenses, net of asset dispositions		72,971	76,784
Operating taxes and licenses		17,480	17,535
Communication and utilities		11,407	11,242
Total operating expenses		2,742,712	2,749,632
Operating income	[1]	178,680	194,369
Net interest expense		18,597	15,649
Earnings before income taxes		160,083	178,720
Income taxes		42,343	51,227
Net earnings		$ 117,740	$ 127,493
Weighted average basic shares outstanding (in shares)		99,905	103,242
Basic earnings per share (in dollars per share)		$ 1.18	$ 1.23
Weighted average diluted shares outstanding (in shares)		100,489	104,107
Diluted earnings per share (in dollars per share)		$ 1.17	$ 1.22
Service Excluding Fuel Surcharge [Member]
Operating revenues		$ 2,559,729	$ 2,552,486
Fuel Surcharge [Member]
Operating revenues		$ 361,663	$ 391,515

[1] Refer to the Condensed Consolidated Statements of Earnings for the reconciliation of consolidated operating income to earnings before income taxes.