CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (UNAUDITED) (in thousands) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net loss	$ (89,112)	$ (40,907)	$ (134,585)	$ (556,798)
Other comprehensive loss, net of tax:
Pension liability adjustment	(208)	(255)	(651)	(760)
Total other comprehensive loss, net of tax	(208)	(255)	(651)	(760)
Total comprehensive loss	$ (89,320)	$ (41,162)	$ (135,236)	$ (557,558)