Retirement Plans - Components of Net Periodic Benefit Costs for Pension and Other Postretirement Benefits (Detail) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jul. 01, 2017 |
Jul. 02, 2016 |
Jul. 01, 2017 |
Jul. 02, 2016 |
|
| Pension Benefits [Member] | ||||
| Pension Plans, Postretirement and Other Employee Benefits [Line Items] | ||||
| Service cost | $ 506 | $ 959 | $ 1,012 | $ 1,925 |
| Interest cost | 10,139 | 10,413 | 20,277 | 20,230 |
| Expected return on plan assets | (11,964) | (11,927) | (23,928) | (24,148) |
| Amortization of prior service cost | 34 | 40 | 69 | 79 |
| Amortization of net loss (gain) | 1,050 | 2,268 | 2,101 | 4,128 |
| Settlements | 2,000 | 750 | 2,000 | 1,500 |
| Net periodic benefit costs | 1,765 | 2,503 | 1,531 | 3,714 |
| Other Postretirement Benefits [Member] | ||||
| Pension Plans, Postretirement and Other Employee Benefits [Line Items] | ||||
| Service cost | 9 | 10 | 19 | 19 |
| Interest cost | 72 | 74 | 144 | 148 |
| Amortization of prior service cost | 2 | 1 | 3 | 3 |
| Amortization of net loss (gain) | (13) | (18) | (26) | (36) |
| Net periodic benefit costs | $ 70 | $ 67 | $ 140 | $ 134 |