CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net loss	$ (1,582,961)	$ (409,592)	$ (143,070)
Other comprehensive income (loss):
Change in pension and postretirement obligations, net of tax of $93 in 2015, $(10) in 2014 and $673 in 2013	173	(18)	1,249
Total other comprehensive income (loss), net of tax	173	(18)	1,249
Comprehensive loss	$ (1,582,788)	$ (409,610)	$ (141,821)