Revenue - Revenue Contract Estimates (Details) - USD ($) $ in Thousands |
3 Months Ended | |
|---|---|---|
Mar. 30, 2018 |
Mar. 31, 2017 |
|
| Revenue from Contract with Customer [Abstract] | ||
| Favorable adjustments | $ 4,152 | $ 3,542 |
| Unfavorable adjustments | (1,311) | (823) |
| Net favorable adjustments | 2,841 | 2,719 |
| Net favorable adjustment to operating income | $ 3,400 | $ 2,400 |