CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (33,769)	$ (84,143)	$ (189,492)	$ (240,512)
Other comprehensive income (loss), net of taxes of $0 for all periods:
Foreign currency translation adjustment	3,607	(2,379)	6,595	4,768
Total comprehensive loss	$ (30,162)	$ (86,522)	$ (182,897)	$ (235,744)