Pensions and Postretirement Benefits Other than Pensions - Components of Net Periodic Benefit Costs (Detail) - USD ($) $ in Thousands |
3 Months Ended | |
|---|---|---|
Mar. 31, 2018 |
Mar. 31, 2017 |
|
| Other Postretirement Benefits | ||
| Components of net periodic benefit cost: | ||
| Service cost | $ 487 | $ 501 |
| Interest cost | 2,313 | 2,515 |
| Amortization of prior service credit | (135) | (141) |
| Net periodic benefit cost | 2,665 | 2,875 |
| Domestic | Pension Benefits | ||
| Components of net periodic benefit cost: | ||
| Service cost | 2,580 | 2,465 |
| Interest cost | 9,210 | 9,813 |
| Expected return on plan assets | (13,498) | (13,515) |
| Amortization of actuarial loss | 8,235 | 9,281 |
| Net periodic benefit cost | 6,527 | 8,044 |
| International | Pension Benefits | ||
| Components of net periodic benefit cost: | ||
| Service cost | 0 | 0 |
| Interest cost | 2,906 | 2,770 |
| Expected return on plan assets | (3,155) | (2,707) |
| Amortization of actuarial loss | 1,110 | 1,310 |
| Net periodic benefit cost | $ 861 | $ 1,373 |