Conslidated 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 Comprehensive Income [Abstract]
Net income	$ 29,471	$ 6,164	$ 32,160	$ 1,580
Other comprehensive income (loss):
Foreign currency translation adjustments	30	(767)	(2,259)	44
Change in unrealized gains (losses) on available-for-sale securities, net of tax of $(1,239), $95, $(1,451), and $133, respectively	(1,985)	151	(2,324)	211
Total other comprehensive income (loss)	(1,955)	(616)	(4,583)	255
Comprehensive income	$ 27,516	$ 5,548	$ 27,577	$ 1,835