Shareholders' Equity - Summary of Change in Shareholders' Equity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Shareholders Equity - Summary Of Change In Shareholders Equity Details
Balance at the beginning of the period	$ 82,505	$ 77,109	$ 82,569	$ 76,016
Exercise of stock options	140	70	433	90
Stock repurchased	(3,711)		(4,115)
Options repurchased			(1,752)
Proceeds from stock purchase plan	18		43
Dividends	(465)	(320)	(924)	(639)
Share-based compensation - options	168	217	311	455
Share-based compensation - ESPP	3		8
Tax benefit - stock option exercises	93	22	656	29
Unrealized gain or loss on investments, net of tax	97	(77)	218	(22)
Foreign currency translation adjustment	(20)	129	13	(51)
Net Income during the period	955	1,515	2,323	2,787
Balance at end of the period	$ 79,783	$ 78,665	$ 79,783	$ 78,665