Revenue - Revenue by Contract Relationship (Details) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Oct. 02, 2020 |
Sep. 27, 2019 |
Oct. 02, 2020 |
Sep. 27, 2019 |
|
| Disaggregation of Revenue [Line Items] | ||||
| Total revenue | $ 352,415 | $ 359,873 | $ 1,040,212 | $ 1,017,368 |
| Prime contractor | ||||
| Disaggregation of Revenue [Line Items] | ||||
| Total revenue | $ 332,564 | 334,402 | 980,301 | $ 954,191 |
| Revenue, percent change | (0.50%) | 2.70% | ||
| Subcontractor | ||||
| Disaggregation of Revenue [Line Items] | ||||
| Total revenue | $ 19,851 | $ 25,471 | $ 59,911 | $ 63,177 |
| Revenue, percent change | (22.10%) | (5.20%) | ||