Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net loss	$ (6,637)	$ (90,896)	$ (294,790)
Change in fair value of derivatives, net of income tax (expense) benefit of ($165), $561 and $2,650, respectively	5,028	(5,697)	(4,473)
Comprehensive loss	$ (1,609)	$ (96,593)	$ (299,263)