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Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2021 | Sep. 30, 2020 | Mar. 31, 2020 | Sep. 30, 2021 | Sep. 30, 2020
Summary Of Significant Accounting Policy [Line Items] |  |  |  |  |
Tax benefit in other comprehensive income (loss) | $ 37 | $ 95 |  | $ 85 | $ 415
ASU 2016-13 [Member] |  |  |  |  |
Summary Of Significant Accounting Policy [Line Items] |  |  |  |  |
Change in Accounting Principle, Accounting Standards Update, Adopted [true false] | true |  |  | true |
Change in Accounting Principle, Accounting Standards Update, Adoption Date | Jan. 01, 2020 |  |  | Jan. 01, 2020 |
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false] | true |  |  | true |
ASU 2019-12 [Member] |  |  |  |  |
Summary Of Significant Accounting Policy [Line Items] |  |  |  |  |
Change in Accounting Principle, Accounting Standards Update, Adopted [true false] | true |  |  | true |
Change in Accounting Principle, Accounting Standards Update, Adoption Date | Apr. 01, 2020 |  |  | Apr. 01, 2020 |
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false] | true |  |  | true |
Adjustments for New Accounting Principle, Early Adoption [Member] |  |  |  |  |
Summary Of Significant Accounting Policy [Line Items] |  |  |  |  |
Tax benefit in other comprehensive income (loss) |  |  | $ (100) |  |
Overstatement Long-term Investment Balance at Remeasured Cost Basis [Member] |  |  |  |  |
Summary Of Significant Accounting Policy [Line Items] |  |  |  |  |
Amount of revision |  |  | 2,800 |  |
Errors in Net Investment Gain [Member] |  |  |  |  |
Summary Of Significant Accounting Policy [Line Items] |  |  |  |  |
Amount of revision |  |  | $ 1,500 |  |

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