CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Revenues:
Transportation	$ 2,998,583	$ 3,044,500	$ 8,593,767	$ 9,122,479
Sourcing	357,171	374,753	1,135,671	1,142,752
Total revenues	3,355,754	3,419,253	9,729,438	10,265,231
Costs and expenses:
Purchased transportation and related services	2,469,939	2,484,409	6,974,556	7,518,895
Purchased products sourced for resale	327,353	346,269	1,038,870	1,048,633
Personnel expenses	256,883	264,077	804,631	783,220
Other selling, general, and administrative expenses	90,312	91,787	267,415	270,752
Total costs and expenses	3,144,487	3,186,542	9,085,472	9,621,500
Income from operations	211,267	232,711	643,966	643,731
Interest and other expense	(7,426)	(6,559)	(22,463)	(22,058)
Income before provision for income taxes	203,841	226,152	621,503	621,673
Provision for income taxes	74,813	86,720	230,422	238,557
Net income	129,028	139,432	391,081	383,116
Other comprehensive income (loss)	518	(6,395)	491	(15,463)
Comprehensive income	$ 129,546	$ 133,037	$ 391,572	$ 367,653
Basic net income per share (in dollars per share)	$ 0.90	$ 0.96	$ 2.73	$ 2.63
Diluted net income per share (in dollars per share)	$ 0.90	$ 0.96	$ 2.73	$ 2.63
Basic weighted average shares outstanding (shares)	142,611	144,578	143,040	145,423
Dilutive effect of outstanding stock awards (shares)	272	204	205	178
Diluted weighted average shares outstanding (shares)	142,883	144,782	143,245	145,601