Stockholders' Investment (Tables)

6 Months Ended

Jun. 30, 2017

Equity [Abstract]

Schedule of changes in stockholders' investment

	Three Months Ended						Six Months Ended
	June 30,						June 30,
	2017			2016			2017			2016
Beginning balance	$	177,940		$	557,471		$	197,468		$	556,439
Net loss	(37,863		)	(2,739		)	(57,806		)	(1,839		)
Share-based compensation	658			577			1,268			1,126
Issuance of warrants	2,571			—			2,571			—
Issuance of restricted stock units, net of taxes paid	(20		)	(13		)	(215		)	(177		)
Tax deficiency on share-based compensation	—			(32		)	—			(285		)
Ending balance	$	143,286		$	555,264		$	143,286		$	555,264