CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (UNAUDITED) (in thousands) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net loss	$ (119,907)	$ (168,681)	$ (45,473)	$ (515,891)
Other comprehensive income (loss), net of tax:
Pension liability adjustment	124	(269)	(443)	(505)
Total other comprehensive income (loss), net of tax	124	(269)	(443)	(505)
Total comprehensive loss	$ (119,783)	$ (168,950)	$ (45,916)	$ (516,396)