Annual report pursuant to Section 13 and 15(d)

Long-Term Debt (Details Textual)

v3.8.0.1
Long-Term Debt (Details Textual) - USD ($)
12 Months Ended
Dec. 30, 2017
Dec. 31, 2016
Debt Instrument [Line Items]    
Revolving line of credit $ 116,000,000 $ 140,000,000
Revolving line of credit 4,082,000 483,000
Revolving Credit Facility [Member]    
Debt Instrument [Line Items]    
Credit facilities, maximum capacity $ 300,000,000  
Expiration date Nov. 22, 2021  
Accordion feature to increase maximum capacity $ 100,000,000  
Revolving line of credit $ 116,000,000 $ 140,000,000
Interest rate in effect 3.15%  
Interest coverage ratio 3.0  
Leverage ratio 3.5  
Swing Loans [Member]    
Debt Instrument [Line Items]    
Credit facilities, maximum capacity $ 20,000,000  
Letter of Credit [Member]    
Debt Instrument [Line Items]    
Credit facilities, maximum capacity $ 10,000,000