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Employee Benefit Plans - Additional Information (Detail) - USD ($) | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2019 | Jun. 30, 2018 | Dec. 31, 2019 | Jun. 30, 2019 | Jun. 30, 2018 | Dec. 31, 2018
Pension Plans, Defined Benefit |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |
Defined benefit plan, employer contributions | $ 0 | $ 0 |  | $ 0 | $ 0 |
Supplemental Executive Retirement Plan |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |
Defined benefit plan, employer contributions | 400,000 |  |  | 800,000 |  |
Obligations under the supplemental plan | $ 20,500,000 |  |  | $ 20,500,000 |  | $ 21,400,000
Supplemental Executive Retirement Plan | Scenario, Forecast |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |
Defined benefit plan, employer contributions |  |  | $ 2,300,000 |  |  |

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