CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (UNAUDITED) (in thousands) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (135,923)	$ (89,112)	$ 198,675	$ (134,585)
Other comprehensive income (loss), net of tax:
Pension liability adjustment	263	(208)	721	(651)
Total other comprehensive income (loss), net of tax	263	(208)	721	(651)
Total comprehensive income (loss)	$ (135,660)	$ (89,320)	$ 199,396	$ (135,236)

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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