Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Revenues	$ 478,920	$ 466,546
Operating expenses:
Purchased transportation costs	316,285	308,039
Personnel and related benefits	74,410	68,349
Other operating expenses	96,830	73,873
Depreciation and amortization	9,305	9,209
Total operating expenses	496,830	459,470
Operating (loss) income	(17,910)	7,076
Interest expense	6,525	5,608
(Loss) income before (benefit from) provision for income taxes	(24,435)	1,468
(Benefit from) provision for income taxes	(4,492)	568
Net (loss) income	$ (19,943)	$ 900
(Loss) earnings per share:
Basic (in dollars per share)	$ (0.52)	$ 0.02
Diluted (in dollars per share)	$ (0.52)	$ 0.02
Weighted average common stock outstanding:
Basic (in shares)	38,365	38,284
Diluted (in shares)	38,365	38,372