Condensed Consolidated Statements of Earnings (Unaudited) - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Operating revenues		$ 11,999,096	$ 12,087,204	$ 12,829,665
Operating expenses:
Rents and purchased transportation		5,306,405	5,378,336	5,872,591
Salaries, wages and employee benefits		3,236,319	3,232,440	3,257,484
Depreciation and amortization		714,785	761,141	737,954
Fuel and fuel taxes		633,324	652,129	751,497
Operating supplies and expenses		511,639	495,375	509,354
Insurance and claims		334,689	313,664	315,678
General and administrative expenses, net of asset dispositions		281,508	306,355	274,564
Operating taxes and licenses		71,570	72,547	74,996
Communication and utilities		43,788	43,992	42,351
Total operating expenses		11,134,027	11,255,979	11,836,469
Operating income	[1]	865,069	831,225	993,196
Interest income		4,249	7,311	7,624
Interest expense		75,206	79,020	65,933
Earnings before income taxes		794,112	759,516	934,887
Income taxes		195,830	188,630	206,600
Net earnings		$ 598,282	$ 570,886	$ 728,287
Weighted average basic shares outstanding (in shares)		97,090	101,947	103,440
Basic earnings per share (in dollars per share)		$ 6.16	$ 5.6	$ 7.04
Weighted average diluted shares outstanding (in shares)		97,688	102,754	104,451
Diluted earnings per share (in dollars per share)		$ 6.12	$ 5.56	$ 6.97
Service Excluding Fuel Surcharge [Member]
Operating revenues		$ 10,523,422	$ 10,557,709	$ 10,978,387
Fuel Surcharge [Member]
Operating revenues		$ 1,475,674	$ 1,529,495	$ 1,851,278

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