Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net income	$ 53,102	$ 50,935	$ 44,323
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	1,648	(191)	(852)
Total other comprehensive income (loss), net of tax	1,648	(191)	(852)
Comprehensive income	$ 54,750	$ 50,744	$ 43,471