UNAUDITED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 31,089	$ 12,058	$ 49,205	$ 16,545
Other comprehensive income (loss):
Unrealized (losses) gains on available-for-sale securities (net of taxes of $7, $7, $95 and $129, respectively)	(932)	11	(1,138)	170
Reclassification adjustment for losses on available-for-sale securities included in net income (net of taxes of $0, $0, $0 and $79, respectively)	0	0	0	143
Unrealized loss on interest rate hedge (net of taxes of $0, $0, $0 and $0)	(310)	0	(310)	0
Foreign currency translation adjustments (including a tax benefit of $5.6 million in the nine months ended September 30, 2018)	9,832	23,698	(11,650)	44,545
Other comprehensive income (loss)	8,590	23,709	(13,098)	44,858
Comprehensive income	$ 39,679	$ 35,767	$ 36,107	$ 61,403