Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement Of Income And Comprehensive Income [Abstract]
NET LOSS	$ (203,806)	$ (971,410)	$ (183,176)
Other comprehensive income (loss):
Pension obligation adjustment, net of tax		548	(1,716)
TOTAL COMPREHENSIVE LOSS	$ (203,806)	$ (970,862)	$ (184,892)