CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues:
Total revenues	$ 23,102,138	$ 16,207,106	$ 15,309,508
Costs and expenses:
Personnel expenses	1,543,610	1,242,867	1,298,528
Other selling, general, and administrative expenses	526,371	496,122	497,806
Total costs and expenses	22,020,030	15,533,838	14,519,532
Income from operations	1,082,108	673,268	789,976
Interest and other expenses	(59,817)	(44,937)	(47,719)
Income before provision for income taxes	1,022,291	628,331	742,257
Provision for income taxes	178,046	121,910	165,289
Net income	844,245	506,421	576,968
Other comprehensive (loss) income	(15,136)	30,151	(4,214)
Comprehensive income	$ 829,109	$ 536,572	$ 572,754
Basic net income per share (in dollars per share)	$ 6.37	$ 3.74	$ 4.21
Diluted net income per share (in dollars per share)	$ 6.31	$ 3.72	$ 4.19
Basic weighted average shares outstanding (in shares)	132,482	135,532	136,955
Dilutive effect of outstanding stock awards (in shares)	1,352	641	780
Diluted weighted average shares outstanding (in shares)	133,834	136,173	137,735
Transportation
Revenues:
Total revenues	$ 22,046,574	$ 15,147,562	$ 14,322,295
Costs and expenses:
Purchased services and products	18,994,574	12,834,608	11,839,433
Sourcing
Revenues:
Total revenues	1,055,564	1,059,544	987,213
Costs and expenses:
Purchased services and products	$ 955,475	$ 960,241	$ 883,765