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Retirement Plans - Additional Information (Detail) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items] |  |  |
Expected period of return on plan assets, years | 10 years | 10 years |
Minimum contribution by employer | $ 0 | $ 0 | $ 0
Discretionary contributions by employer | 0 | 30,000,000.0 | 0
Fair value of plan assets | $ 262,800,000 | 243,700,000 | 220,000,000.0
Foreign Retirement Plans [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Matching contributions by employer, percentage | 100.00% |  |
Percentage of eligible compensation for matching contributions by employer | 5.00% |  |
Contribution expense to plan | $ 44,300,000 | 39,800,000 | 34,900,000
Additional percentage of eligible compensation for matching contributions by employer | 5.00% |  |
Qualified Contributory Savings and Thrift 401(k) Plan [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Matching contributions by employer, percentage | 100.00% |  |
Percentage of eligible compensation for matching contributions by employer | 5.00% |  |
Matching contributions vesting schedule | 5 years |  |
Contribution expense to plan | $ 63,600,000 | 59,400,000 | 53,900,000
Nonqualified Deferred Compensation Plan [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Percentage of eligible compensation for matching contributions by employer | 5.00% |  |
Contribution expense to plan | $ 7,800,000 | 7,100,000 | $ 6,500,000
Fair value of plan assets | $ 497,300,000 | $ 452,900,000 |

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