Condensed Consolidated Statements Of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Net income	$ 6,397	$ 5,489	$ 15,415	$ 7,989
Other comprehensive income (loss), net of tax:
Change in unrealized losses on securities, net of tax			5
Foreign currency translation adjustments	176	862	(420)	1,164
Total other comprehensive income (loss), net of tax	188	830	(420)	1,110
Comprehensive income	6,585	6,319	14,995	9,099
Auction Rate Securities [Member]
Other comprehensive income (loss), net of tax:
Change in unrealized losses on securities, net of tax	5	(17)	(12)	(32)
Available-for-sale Securities [Member]
Other comprehensive income (loss), net of tax:
Change in unrealized losses on securities, net of tax	$ 7	$ (15)	$ 12	$ (22)