Annual report pursuant to Section 13 and 15(d)

Stock Incentive Plans (Details)

v3.8.0.1
Stock Incentive Plans (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2017
Dec. 25, 2016
Dec. 27, 2015
Share-based compensation plan disclosures      
Total stock-based compensation cost $ 4.8 $ 4.5 $ 4.7
Income tax benefits from stock-based compensation cost 1.5 $ 0.4 2.0
Total unrecognized compensation cost $ 4.9    
Stock Options      
Share-based compensation plan disclosures      
Shares outstanding 469,000 408,000  
Weighted average remaining vesting period 1 year 4 months 24 days    
Restricted Stock      
Share-based compensation plan disclosures      
Weighted average remaining vesting period 1 year 3 months 1 day    
Number of common shares issued per RSU or PSU 1    
Restricted Stock | Board of Directors      
Share-based compensation plan disclosures      
Vesting period 1 year    
Performance Stock Units      
Share-based compensation plan disclosures      
Weighted average remaining vesting period 1 year 11 months 27 days    
Number of common shares issued per RSU or PSU 1    
Performance Stock Units | Tranche One      
Share-based compensation plan disclosures      
Vesting percentage 33.33%    
Performance Stock Units | Tranche Two      
Share-based compensation plan disclosures      
Vesting percentage 33.33%    
Performance Stock Units | Tranche Three      
Share-based compensation plan disclosures      
Vesting percentage 33.33%    
2017 and 2007 Performance Incentive Plans      
Share-based compensation plan disclosures      
Period following the change in control during which termination of an individual without cause will trigger vesting of award 2 years    
2017 Stock Plan      
Share-based compensation plan disclosures      
Maximum number of shares of the company's common stock that may be issued or transferred 630,182    
2007 Stock Plan      
Share-based compensation plan disclosures      
Shares outstanding 468,657    
2007 Stock Plan | Time Based RSUs      
Share-based compensation plan disclosures      
Vesting period 4 years    
Other stock-based compensation plans      
Share-based compensation plan disclosures      
Expiration term 10 years    
Long-Term Cash Incentive Plan | Deferred compensation, excluding share-based payments and retirement benefits      
Share-based compensation plan disclosures      
Performance and vesting period 3 years 3 years  
Compensation expense $ 0.4 $ (2.3) 3.3
Payments of performance stock awards 0.7 3.4 $ 1.8
Long-Term Cash Incentive Plan | Deferred compensation, excluding share-based payments and retirement benefits | Accrued payroll liabilities and payroll-related liabilities      
Share-based compensation plan disclosures      
Long-term cash incentive plan liability $ 0.4 $ 0.7