CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenues:
Transportation	$ 3,130,722	$ 3,042,102	$ 6,077,979	$ 5,848,879
Sourcing	414,366	460,816	767,999	796,624
Total revenues	3,545,088	3,502,918	6,845,978	6,645,503
Costs and expenses:
Purchased transportation and related services	2,582,374	2,555,959	5,034,486	4,932,347
Purchased products sourced for resale	378,696	425,922	702,364	734,884
Personnel expenses	263,999	238,986	519,143	459,283
Other selling, general, and administrative expenses	90,924	81,669	178,965	161,636
Total costs and expenses	3,315,993	3,302,536	6,434,958	6,288,150
Income from operations	229,095	200,382	411,020	357,353
Interest and other expense	(5,894)	(6,252)	(15,499)	(12,383)
Income before provision for income taxes	223,201	194,130	395,521	344,970
Provision for income taxes	85,993	75,534	151,837	133,187
Net income	137,208	118,596	243,684	211,783
Other comprehensive income (loss)	4,130	(743)	(9,068)	(1,079)
Comprehensive income	$ 141,338	$ 117,853	$ 234,616	$ 210,704
Basic net income per share (in dollars per share)	$ 0.94	$ 0.80	$ 1.67	$ 1.43
Diluted net income per share (in dollars per share)	$ 0.94	$ 0.80	$ 1.67	$ 1.43
Basic weighted average shares outstanding (in shares)	145,515	147,826	145,856	148,167
Dilutive effect of outstanding stock awards (in shares)	164	148	164	126
Diluted weighted average shares outstanding (in shares)	145,679	147,974	146,020	148,293