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	$ 4,450	$ 3,043	$ 9,976	$ 7,266
Other comprehensive income (loss), net of taxes:
Foreign currency translation	(129)	(2,333)	(2,062)	(2,394)
Net change in market value of investments		(59)	47	(23)
Other comprehensive loss	(129)	(2,392)	(2,015)	(2,417)
Comprehensive income	$ 4,321	$ 651	$ 7,961	$ 4,849