Securities - Realized Gains and Losses on Sales of Investment Securities (Detail) - USD ($) |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2021 |
Sep. 30, 2020 |
Sep. 30, 2021 |
Sep. 30, 2020 |
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| Investments Debt And Equity Securities [Abstract] | ||||
| Gross realized gains on sales of securities | $ 99,000 | $ 15,712,000 | ||
| Net realized gains on sales of securities | 99,000 | 15,712,000 | ||
| Proceeds from sales of securities | $ 0 | $ 0 | $ 8,035,000 | $ 495,566,000 |
| X | ||||||||||
- Definition Amount of realized gain from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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| X | ||||||||||
- Definition Amount of realized gain (loss) from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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| X | ||||||||||
- References No definition available.
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- Definition Amount of cash inflow from sale, maturity, prepayment and call of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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