CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Revenues:
Transportation	$ 2,947,257	$ 2,806,777
Sourcing	353,633	335,808
Total revenues	3,300,890	3,142,585
Costs and expenses:
Purchased transportation and related services	2,452,112	2,376,388
Purchased products sourced for resale	323,668	308,962
Personnel expenses	255,144	220,297
Other selling, general, and administrative expenses	88,041	79,967
Total costs and expenses	3,118,965	2,985,614
Income from operations	181,925	156,971
Interest and other expense	(9,605)	(6,131)
Income before provision for income taxes	172,320	150,840
Provision for income taxes	65,844	57,653
Net income	106,476	93,187
Other comprehensive loss	(13,198)	(337)
Comprehensive income	$ 93,278	$ 92,850
Basic net income per share (in dollars per share)	$ 0.73	$ 0.63
Diluted net income per share (in dollars per share)	$ 0.73	$ 0.63
Basic weighted average shares outstanding (in shares)	146,204	148,517
Dilutive effect of outstanding stock awards (in shares)	179	491
Diluted weighted average shares outstanding (in shares)	146,383	149,008