Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Consolidated Statements Of Comprehensive Income [Abstract]
Net income	$ 17,512	$ 21,742	$ 44,375	$ 45,479
Other comprehensive income (loss):
Foreign currency translation adjustments	1,313	299	4,434	815
Unrealized gain on investments, net of tax	3	1	19	17
Unrealized gain (loss) on derivative, net of tax	89	765	254	(2,134)
Other	0	(1)	(13)	(1)
Net current period other comprehensive gain (loss)	1,405	1,064	4,694	(1,303)
Comprehensive income	$ 18,917	$ 22,806	$ 49,069	$ 44,176