Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Consolidated Statements of Comprehensive Income (Loss)
Net income (loss)	$ 473,463	$ 109,310	$ 686
Other comprehensive loss, net of tax:
Foreign currency translation adjustment during the period	3,223	(122)	(3,272)
Other comprehensive income (loss)	3,223	(122)	(3,272)
Comprehensive income (loss)	$ 476,686	$ 109,188	$ (2,586)