Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Consolidated Statements Of Comprehensive Income [Abstract]
Net income	$ 20,565	$ 16,906	$ 55,980	$ 57,903
Other comprehensive loss:
Foreign currency translation adjustments	378	(2,712)	(2,386)	(2,945)
Unrealized gain (loss) on investments, net of tax	10	1,496	(23)	1,342
Other	(3)	(8)	(10)	(23)
Net current period other comprehensive loss	385	(1,224)	(2,419)	(1,626)
Comprehensive income	$ 20,950	$ 15,682	$ 53,561	$ 56,277