CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues:
Total revenues	$ 15,309,508	$ 16,631,172	$ 14,869,380
Costs and expenses:
Personnel expenses	1,298,528	1,343,542	1,179,527
Other selling, general, and administrative expenses	497,806	449,610	413,404
Total costs and expenses	14,519,532	15,719,089	14,094,261
Income from operations	789,976	912,083	775,119
Interest and other expenses	(47,719)	(31,810)	(46,656)
Income before provision for income taxes	742,257	880,273	728,463
Provision for income taxes	165,289	215,768	223,570
Net income	576,968	664,505	504,893
Other comprehensive (loss) income	(4,214)	(53,475)	42,982
Comprehensive income	$ 572,754	$ 611,030	$ 547,875
Basic net income per share (in dollars per share)	$ 4.21	$ 4.78	$ 3.59
Diluted net income per share (in dollars per share)	$ 4.19	$ 4.73	$ 3.57
Basic weighted average shares outstanding (in shares)	136,955	139,010	140,610
Dilutive effect of outstanding stock awards (in shares)	780	1,395	772
Diluted weighted average shares outstanding (in shares)	137,735	140,405	141,382
Transportation
Revenues:
Total revenues	$ 14,322,295	$ 15,515,921	$ 13,502,906
Costs and expenses:
Purchased services and products	11,839,433	12,922,177	11,257,290
Sourcing
Revenues:
Total revenues	987,213	1,115,251	1,366,474
Costs and expenses:
Purchased services and products	$ 883,765	$ 1,003,760	$ 1,244,040