Revenue - Revenue by Customer (Details) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 28, 2018 |
Sep. 29, 2017 |
Sep. 28, 2018 |
Sep. 29, 2017 |
|
| Disaggregation of Revenue [Line Items] | ||||
| Total revenue | $ 308,095 | $ 269,625 | $ 949,744 | $ 819,005 |
| Army | ||||
| Disaggregation of Revenue [Line Items] | ||||
| Total revenue | 224,038 | 214,152 | 700,265 | 682,891 |
| Air Force | ||||
| Disaggregation of Revenue [Line Items] | ||||
| Total revenue | 64,278 | 49,435 | 189,954 | 119,896 |
| Navy | ||||
| Disaggregation of Revenue [Line Items] | ||||
| Total revenue | 8,567 | 6,038 | 26,912 | 16,218 |
| Other | ||||
| Disaggregation of Revenue [Line Items] | ||||
| Total revenue | $ 11,212 | $ 0 | $ 32,613 | $ 0 |