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Income Taxes - Additional Information (Detail) - USD ($) | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2020 | Sep. 30, 2019 | Sep. 30, 2020 | Sep. 30, 2019 | Dec. 31, 2019
Income Tax Contingency [Line Items] |  |  |  |  |
Pretax income | $ 10,141,000 | $ 11,784,000 | $ 20,427,000 | $ 30,193,000 |
Income tax expense (benefit) | 3,614,000 | $ 3,141,000 | 8,775,000 | $ 10,654,000 |
Pension, restructuring and other non recurring costs |  |  | 10,200,000 |  |
Offsetting of income tax |  |  | 5,000,000.0 |  |
Decrease in valuation allowance |  |  | (6,200,000) |  |
Gross unrecognized tax benefits | 34,700,000 |  | 34,700,000 |  | $ 30,500,000
Unrecognized tax benefits that would impact effective tax rate | 23,900,000 |  | 23,900,000 |  |
Minimum [Member] |  |  |  |  |
Income Tax Contingency [Line Items] |  |  |  |  |
Gross unrecognized tax benefits balance may decrease within the next twelve months | 0 |  | 0 |  |
Maximum [Member] |  |  |  |  |
Income Tax Contingency [Line Items] |  |  |  |  |
Gross unrecognized tax benefits balance may decrease within the next twelve months | $ 7,000,000.0 |  | 7,000,000.0 |  |
Pension, Restructuring, and Other Non-Recurring Costs [Member] |  |  |  |  |
Income Tax Contingency [Line Items] |  |  |  |  |
Income tax expense (benefit) |  |  | $ 0 |  |

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