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)	$ (19,425)	$ 18,518	$ 92,894
Other comprehensive income, net of tax:
Change in unrealized gains/losses on available-for-sale securities, net	929	342	(204)
Change in unrealized gains/losses on derivative contracts, net (net of tax effect of $105, $47, and $97)	1,617	399	2,555
Other comprehensive income	2,546	741	2,351
Total comprehensive income (loss), net of tax	$ (16,879)	$ 19,259	$ 95,245