Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 19,343	$ 12,629	$ 34,669	$ 26,122
Cumulative translation adjustment and foreign currency exchange hedge, net of tax	(73)	(148)	43	(280)
Unrealized net loss on securities available-for-sale, net of tax	(9)	(56)	(515)	(255)
Comprehensive Income	$ 19,261	$ 12,425	$ 34,197	$ 25,587