Annual report pursuant to Section 13 and 15(d)

Share-Based Compensation and Other Compensation Matters (Details 3)

v3.8.0.1
Share-Based Compensation and Other Compensation Matters (Details 3) - Performance share units [Member] - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Jan. 01, 2017
Mar. 01, 2016
Mar. 05, 2015
Mar. 06, 2014
Mar. 01, 2013
Dec. 31, 2017
2013 PSU Grants [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Stock awards granted (in shares or units)         69,579  
Grant date fair value         $ 1,867  
Unvested at the end of the period (in shares)           0
2014 PSU Grants [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Stock awards granted (in shares or units)       49,103    
Grant date fair value       $ 1,723    
Unvested at the end of the period (in shares)           0
2015 PSU Grants [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Stock awards granted (in shares or units)     45,656      
Grant date fair value     $ 1,678      
Unvested at the end of the period (in shares)           15,767
Grant date fair value (in dollars per share)     $ 36.76      
2016 PSU Grants [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Stock awards granted (in shares or units)   26,299        
Grant date fair value   $ 1,000        
Unvested at the end of the period (in shares)           24,850
Grant date fair value (in dollars per share)   $ 38.21        
2017 PSU Grants [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Stock awards granted (in shares or units) 39,351          
Grant date fair value $ 1,400          
Unvested at the end of the period (in shares)           39,351
Grant date fair value (in dollars per share) $ 38.43