UNAUDITED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 12,058	$ (10,255)	$ 16,545	$ (27,160)
Other comprehensive income (loss):
Unrealized gains (losses) on available-for-sale securities (net of tax (benefit) of $7, $(238), $129 and $(238), respectively)	11	(164)	170	(358)
Reclassification adjustment for losses on available-for-sale securities included in net income (loss) (net of taxes of $0, $0, $79 and $0, respectively)	0	0	143	0
Foreign currency translation adjustments	23,698	(1,147)	44,545	43,706
Other comprehensive income (loss)	23,709	(1,311)	44,858	43,348
Comprehensive income (loss)	$ 35,767	$ (11,566)	$ 61,403	$ 16,188