CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues:
Transportation	$ 11,921,974	$ 11,069,710	$ 9,685,415
Sourcing	1,533,555	1,669,134	1,620,183
Payment Services	14,538	13,232	53,515
Total revenues	13,470,067	12,752,076	11,359,113
Costs and expenses:
Purchased transportation and related services	10,042,250	9,371,315	8,157,278
Purchased products sourced for resale	1,418,009	1,542,184	1,483,745
Purchased payment services	2,156	2,482	519
Personnel expenses	939,021	826,661	766,006
Other selling, general, and administrative expenses	320,213	326,784	276,245
Total costs and expenses	12,721,649	12,069,426	10,683,793
Income from operations	748,418	682,650	675,320
Interest and other (expense) income	(24,987)	(9,289)	283,142
Income before provision for income taxes	723,431	673,361	958,462
Provision for income taxes	273,720	257,457	364,658
Net income	449,711	415,904	593,804
Other comprehensive loss	(17,990)	(1,275)	(230)
Comprehensive income	$ 431,721	$ 414,629	$ 593,574
Basic net income per share (in dollars per share)	$ 3.06	$ 2.65	$ 3.68
Diluted net income per share (in dollars per share)	$ 3.05	$ 2.65	$ 3.67
Basic weighted average shares outstanding (in shares)	147,202	156,915	161,557
Dilutive effect of outstanding stock awards (in shares)	340	165	389
Diluted weighted average shares outstanding (in shares)	147,542	157,080	161,946