Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 27,897	$ 22,340	$ 77,105	$ 61,646
Foreign currency translation adjustment	(1,891)	(1,697)	(2,018)	(420)
Comprehensive income	$ 26,006	$ 20,643	$ 75,087	$ 61,226