Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Operating Income (Loss) [Abstract]
Revenues	$ 183,020	$ 115,315	$ 341,711	$ 229,859
Cost of revenues	148,431	102,803	278,021	214,376
Selling, general and administrative expenses	26,630	21,435	52,027	44,927
Other operating income, net	(9)	(713)	(51)	(2,409)
Impairments and other charges	0	6,925	0	6,925
Operating income (loss)	7,968	(15,135)	11,714	(33,960)
Foreign currency exchange loss (gain)	534	(746)	926	(1,201)
Interest expense, net	3,441	3,022	6,659	5,103
Gain on extinguishment of debt	0	0	0	(1,894)
Income (loss) from operations before income taxes	3,993	(17,411)	4,129	(35,968)
Provision (benefit) for income taxes	2,361	(3,507)	3,480	(8,764)
Net income (loss)	$ 1,632	$ (13,904)	$ 649	$ (27,204)
Loss per common share - basic (in dollars per share)	$ 0.02	$ (0.17)	$ 0.01	$ (0.33)
Loss per common share - diluted (in dollars per share)	$ 0.02	$ (0.17)	$ 0.01	$ (0.33)