Revenue - Revenue by Service Line (Details) - USD ($) $ in Thousands |
3 Months Ended | |
|---|---|---|
Mar. 30, 2018 |
Mar. 31, 2017 |
|
| Disaggregation of Revenue [Line Items] | ||
| Total revenue | $ 320,516 | $ 290,063 |
| Facility and logistics services | ||
| Disaggregation of Revenue [Line Items] | ||
| Total revenue | 231,825 | 220,448 |
| Information technology and network communications services | ||
| Disaggregation of Revenue [Line Items] | ||
| Total revenue | $ 88,691 | $ 69,615 |