Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating Income (Loss) [Abstract]
Revenues	$ 227,293	$ 158,691
Cost of revenues	186,455	129,590
Selling, general and administrative expenses	26,954	25,397
Other operating (income) loss, net	46	(42)
Operating income	13,838	3,746
Foreign currency exchange loss	225	392
Interest expense, net	3,300	3,218
Income from operations before income taxes	10,313	136
Provision for income taxes	3,091	1,119
Net income (loss)	$ 7,222	$ (983)
Income (loss) per common share - basic (in dollars per share)	$ 0.08	$ (0.01)
Income (loss) per common share - diluted (in dollars per share)	$ 0.08	$ (0.01)