Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 18,213	$ 13,482	$ 52,883	$ 39,604
Net cumulative translation adjustment and foreign currency exchange hedge, net of tax of $(242),$(179),$(215) and $(363),respectively	(384)	(356)	(341)	(636)
Net unrealized gain (loss) on securities available-for-sale, net of tax of $11,$(40),$(14) and $(174), respectively	18	(44)	(23)	(246)
Less: reclassification adjustment for realized gain on the sale of securities available- for-sale included in Other Income, net of tax$0,$0,$(299) and $(34),respectively			(474)	(53)
Net changed in unrealized gain (loss) on securities available-for-sale, net of tax	18	(44)	(497)	(299)
Comprehensive Income	$ 17,847	$ 13,082	$ 52,045	$ 38,669