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Securities - Additional Information (Detail) - USD ($) |  | 6 Months Ended
--- | --- | ---
Jan. 10, 2022 | Jun. 30, 2023 | Jun. 30, 2022
Debt Securities, Available-for-Sale [Line Items] |  |  |
Sale of low yielding securities |  |  | $ 226,000,000
Debt securities. average yield percentage |  |  | 0.16%
Reinvested in debt securities |  |  | $ 220,000,000
Reinvested debt securities, average yield percentage |  |  | 1.86%
Proceeds from sales of available for sale securities |  | $ 0 | $ 222,473,000
Avaliable for sale of debt securities realized gains or losses |  | $ 0 |
United States Treasury Notes [Member] |  |  |
Debt Securities, Available-for-Sale [Line Items] |  |  |
Debt securities purchased at par value | $ 600,000,000 |  |
Debt securities. average yield percentage | 1.42% |  |
Debt securities, average maturity period | 53 months |  |

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