Revenue - Revenue by Contract Type (Details) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jul. 02, 2021
Jul. 03, 2020
Jul. 02, 2021
Jul. 03, 2020
Disaggregation of Revenue [Line Items]        
Total revenue $ 470,845 $ 336,063 $ 904,849 $ 687,797
Cost-plus and cost-reimbursable        
Disaggregation of Revenue [Line Items]        
Total revenue $ 359,429 242,740 $ 664,676 499,059
Revenue, percent change 48.10%   33.20%  
Firm-fixed-price        
Disaggregation of Revenue [Line Items]        
Total revenue $ 111,416 $ 93,323 $ 240,173 $ 188,738
Revenue, percent change 19.40%   27.30%