CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 152,858	$ (4,670)	$ (32,900)
Other comprehensive income (loss):
Foreign currency translation adjustments	7,620	(2,057)	(7,910)
Foreign currency adjustments to net income upon liquidation of investment in foreign entities	(488)	0	0
Other comprehensive income (loss)	7,132	(2,057)	(7,910)
Comprehensive income (loss)	$ 159,990	$ (6,727)	$ (40,810)