Description of Business and Summary of Significant Accounting Policies - Summary of Cumulative Catch-Up Adjustments (Details) (Contracts Accounted for under Percentage of Completion, USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 27, 2015
Mar. 29, 2014
Contracts Accounted for under Percentage of Completion
   
Concentration Risk [Line Items]    
Favorable adjustments $ 2,836 $ 3,571
Unfavorable adjustments (1,773) (791)
Net favorable adjustments $ 1,063 $ 2,780