Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 11,996	$ 10,865	$ 13,024
Other comprehensive income (loss), net of taxes:
Foreign currency translation	(3,187)	(3,977)	826
Net change in market value of investments	(26)	(90)	1,040
Other comprehensive income (loss)	(3,213)	(4,067)	1,866
Comprehensive income	$ 8,783	$ 6,798	$ 14,890