Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 4,289	$ 6,185	$ 4,223	$ 8,354
Other comprehensive income (loss), net of taxes:
Foreign currency translation	(106)	16	(61)	(1,339)
Net change in market value of investments	25	(370)	36	(416)
Other comprehensive loss	(81)	(354)	(25)	(1,755)
Comprehensive income	$ 4,208	$ 5,831	$ 4,198	$ 6,599