Condensed Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues:
Total revenues	$ 4,224,800	$ 3,856,132	$ 11,657,654	$ 11,516,182
Costs and expenses:
Personnel expenses	302,904	320,563	933,607	999,547
Other selling, general, and administrative expenses	118,130	111,783	371,606	354,730
Total costs and expenses	4,056,561	3,655,047	11,191,188	10,863,012
Income from operations	168,239	201,085	466,466	653,170
Interest and other expense	(7,465)	(13,180)	(32,904)	(36,935)
Income before provision for income taxes	160,774	187,905	433,562	616,235
Provision for income taxes	24,245	41,011	74,948	138,373
Net income	136,529	146,894	358,614	477,862
Other comprehensive income (loss), net of tax	13,236	(18,576)	5,294	(18,967)
Comprehensive income	$ 149,765	$ 128,318	$ 363,908	$ 458,895
Basic net income per share (in dollars per share)	$ 1.01	$ 1.08	$ 2.65	$ 3.48
Diluted net income per share (in dollars per share)	$ 1.00	$ 1.07	$ 2.63	$ 3.45
Basic weighted average shares outstanding (shares)	135,671	136,380	135,385	137,274
Dilutive effect of outstanding stock awards (shares)	1,457	1,096	752	1,099
Diluted weighted average shares outstanding (shares)	137,128	137,476	136,137	138,373
Transportation
Revenues:
Total revenues	$ 3,944,981	$ 3,608,346	$ 10,835,710	$ 10,751,890
Costs and expenses:
Purchased products and services	3,378,651	2,999,979	9,141,354	8,826,233
Sourcing
Revenues:
Total revenues	279,819	247,786	821,944	764,292
Costs and expenses:
Purchased products and services	$ 256,876	$ 222,722	$ 744,621	$ 682,502