Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation Plans (Details)

v3.6.0.2
Stock-Based Compensation Plans (Details) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Mar. 01, 2016
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Mar. 02, 2015
May 06, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Shares available for issuance (in shares)   476,140        
Stock-based compensation   $ 2,109 $ 2,081 $ 1,739    
Tax withholding associated with awards issued   499 342 314    
Compensation expense not yet recognized   $ 1,100        
Weighted average amortization period of compensation not yet recognized   1 year 10 months 24 days        
Restricted Stock            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Stock-based compensation   $ 2,099 2,040 1,614    
Stock-based compensation included in costs and operating expenses   2,109 2,081 1,739    
Income tax benefit recognized for stock-based compensation   (811) (800) (669)    
Total stock-based compensation expense, net of income tax benefit   1,298 1,281 1,070    
Restricted Stock | Non-employee Directors            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Stock-based compensation   544 617 510    
Restricted Stock | Employee            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Stock-based compensation   $ 1,555 $ 1,423 $ 1,104    
Restricted Stock Plan 2006            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Shares authorized (in shares)   1,000,000       500,000
Restricted Stock Plan 2006 | Non-employee Directors            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Restricted stock awarded (in shares)   17,600 18,000      
Stock-based compensation   $ 544 $ 617      
Restricted Stock Plan 2006 | Employee            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Restricted stock awarded (in shares) 30,020          
Grant date fair value (in dollars per share) $ 31.88          
Vested award is paid in our shares 100.00%       100.00%  
Vesting period   3 years        
Restricted Stock Plan 2006 | Restricted Stock            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Grant date fair value (in dollars per share)   $ 30.89 $ 34.29