Restructuring (Details) (Severance and benefit related costs, USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 27, 2015
Mar. 29, 2014
Severance and benefit related costs
   
Restructuring Reserve [Roll Forward]    
Beginning balance $ 750 $ 1,274
Adjustments (21) 0
Severance and benefit related costs 0 0
Payments (201) (756)
Ending balance $ 528 $ 518