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
3 Months Ended 9 Months Ended
Sep. 29, 2017
Sep. 30, 2016
Sep. 29, 2017
Sep. 30, 2016
Concentration Risk [Line Items]        
Favorable adjustments $ 5,779 $ 2,374 $ 14,104 $ 9,238
Unfavorable adjustments (2,111) (1,202) (5,518) (5,036)
Net favorable adjustments $ 3,668 $ 1,172 $ 8,586 $ 4,202