XML 85 R72.htm IDEA: XBRL DOCUMENT v3.6.0.2
Stockholders' Equity and Stock Plans - Dividends (Details) - USD ($)
$ / shares in Units, $ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Equity [Abstract]        
Cash dividends to common stockholders $ 6,223 $ 5,390 $ 4,733  
Cash dividends paid per common share $ 1.02 $ 0.90 $ 0.80  
Retained earnings $ 146,464 $ 129,553    
Stockholders' equity $ 230,563 $ 214,473 $ 200,026 $ 180,887
Period used to determine amount available for payment of dividends based on restriction (in years) 3 years      
Amount of retained earnings available for payment of dividends based on restriction $ 50,800      
Cash held $ 3,500