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Schedule of Fair Value of Pensions Plan Assets by Asset Category (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
--- | --- | --- | ---
Defined Benefit Plan Disclosure |  |  |
Total | $ 325,800 |  |
Group Annuity Insurance Contracts | Significant Unobservable Inputs (Level 3) |  |  |
Defined Benefit Plan Disclosure |  |  |
Total | 3,166 | $ 29,456 | $ 29,392
United States Pension Plans, Defined Benefit |  |  |
Defined Benefit Plan Disclosure |  |  |
Total | 324,506 | 307,304 | 298,404
United States Pension Plans, Defined Benefit | Quoted Prices in Active Markets for Identical Instruments (Level 1) |  |  |
Defined Benefit Plan Disclosure |  |  |
Total | 3,217 | 3,023 |
United States Pension Plans, Defined Benefit | Significant Other Observable Inputs (Level 2) |  |  |
Defined Benefit Plan Disclosure |  |  |
Total | 318,123 | 301,210 |
United States Pension Plans, Defined Benefit | Significant Unobservable Inputs (Level 3) |  |  |
Defined Benefit Plan Disclosure |  |  |
Total | 3,166 | 3,071 |
United States Pension Plans, Defined Benefit | Corporate Debt Securities |  |  |
Defined Benefit Plan Disclosure |  |  |
Total | 260,294 | 246,528 |
United States Pension Plans, Defined Benefit | Corporate Debt Securities | Significant Other Observable Inputs (Level 2) |  |  |
Defined Benefit Plan Disclosure |  |  |
Total | 260,294 | 246,528 |
United States Pension Plans, Defined Benefit | US Government Debt Securities |  |  |
Defined Benefit Plan Disclosure |  |  |
Total | 25,709 | 24,322 |
United States Pension Plans, Defined Benefit | US Government Debt Securities | Significant Other Observable Inputs (Level 2) |  |  |
Defined Benefit Plan Disclosure |  |  |
Total | 25,709 | 24,322 |
United States Pension Plans, Defined Benefit | Global equity Securities |  |  |
Defined Benefit Plan Disclosure |  |  |
Total | 32,120 | 30,360 |
United States Pension Plans, Defined Benefit | Global equity Securities | Significant Other Observable Inputs (Level 2) |  |  |
Defined Benefit Plan Disclosure |  |  |
Total | 32,120 | 30,360 |
United States Pension Plans, Defined Benefit | Group Annuity Insurance Contracts |  |  |
Defined Benefit Plan Disclosure |  |  |
Total | 3,166 | 3,071 |
United States Pension Plans, Defined Benefit | Group Annuity Insurance Contracts | Significant Unobservable Inputs (Level 3) |  |  |
Defined Benefit Plan Disclosure |  |  |
Total | 3,166 | 3,071 |
United States Pension Plans, Defined Benefit | Cash and Cash Equivalents |  |  |
Defined Benefit Plan Disclosure |  |  |
Total | 3,217 | 3,023 |
United States Pension Plans, Defined Benefit | Cash and Cash Equivalents | Quoted Prices in Active Markets for Identical Instruments (Level 1) |  |  |
Defined Benefit Plan Disclosure |  |  |
Total | 3,217 | 3,023 |
Foreign Pension Plans, Defined Benefit |  |  |
Defined Benefit Plan Disclosure |  |  |
Total | 1,307 | 27,571 | $ 28,141
Foreign Pension Plans, Defined Benefit | Quoted Prices in Active Markets for Identical Instruments (Level 1) |  |  |
Defined Benefit Plan Disclosure |  |  |
Total |  | 62 |
Foreign Pension Plans, Defined Benefit | Significant Other Observable Inputs (Level 2) |  |  |
Defined Benefit Plan Disclosure |  |  |
Total | 1,307 | 1,124 |
Foreign Pension Plans, Defined Benefit | Significant Unobservable Inputs (Level 3) |  |  |
Defined Benefit Plan Disclosure |  |  |
Total |  | 26,385 |
Foreign Pension Plans, Defined Benefit | Group Annuity Insurance Contracts |  |  |
Defined Benefit Plan Disclosure |  |  |
Total |  | 26,385 |
Foreign Pension Plans, Defined Benefit | Group Annuity Insurance Contracts | Significant Unobservable Inputs (Level 3) |  |  |
Defined Benefit Plan Disclosure |  |  |
Total |  | 26,385 |
Foreign Pension Plans, Defined Benefit | Other |  |  |
Defined Benefit Plan Disclosure |  |  |
Total | 1,307 | 1,124 |
Foreign Pension Plans, Defined Benefit | Other | Significant Other Observable Inputs (Level 2) |  |  |
Defined Benefit Plan Disclosure |  |  |
Total | $ 1,307 | 1,124 |
Foreign Pension Plans, Defined Benefit | Cash and Cash Equivalents |  |  |
Defined Benefit Plan Disclosure |  |  |
Total |  | 62 |
Foreign Pension Plans, Defined Benefit | Cash and Cash Equivalents | Quoted Prices in Active Markets for Identical Instruments (Level 1) |  |  |
Defined Benefit Plan Disclosure |  |  |
Total |  | $ 62 |

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