Condensed Consolidated Statements of Comprehensive Loss - 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) income	$ (32,886)	$ 126,520	$ (84,549)	$ 71,690
Other comprehensive income (loss):
Cumulative translation gain (loss)	1		4	(1)
Comprehensive (loss) income	$ (32,885)	$ 126,520	$ (84,545)	$ 71,689