Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Statement [Abstract]
Revenues	$ 101,946	$ 216,412	$ 266,496	$ 427,885
Cost of revenues	112,290	177,933	258,374	352,909
Selling, general and administrative expenses	20,937	28,037	45,633	58,779
Other operating income, net	(742)	(472)	(1,086)	(396)
Operating income (loss)	(30,539)	10,914	(36,425)	16,593
Foreign currency exchange (gain) loss	781	990	2,763	(72)
Interest expense, net	2,912	3,523	6,113	7,179
Gain on extinguishment of debt	(1,334)	0	(419)	0
Income (loss) before income taxes	(32,898)	6,401	(44,882)	9,486
Provision (benefit) for income taxes	(6,654)	2,095	(6,490)	3,898
Net income (loss)	$ (26,244)	$ 4,306	$ (38,392)	$ 5,588
Net income (loss) per common share - basic (in dollars per share)	$ (0.29)	$ 0.05	$ (0.43)	$ 0.06
Net income (loss) per common share - diluted (in dollars per share)	$ (0.29)	$ 0.05	$ (0.43)	$ 0.06