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Junior Subordinated Interest Deferrable Debentures (Key Information) (Details) - USD ($) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2023 | Dec. 31, 2022
Junior subordinated interest deferrable debentures, major types of business trusts |  |
Junior subordinated deferrable interest debentures | $ 108,868,000 | $ 134,642,000
Trust IX |  |
Junior subordinated interest deferrable debentures, major types of business trusts |  |
Junior subordinated deferrable interest debentures | $ 41,238,000 |
Interest rate (as a percent) | 7.28% |
Interest rate index | SOFR |
Spread on interest rate index (as a percent) | 1.62% |
Trust X |  |
Junior subordinated interest deferrable debentures, major types of business trusts |  |
Junior subordinated deferrable interest debentures | $ 21,021,000 |
Interest rate (as a percent) | 7.29% |
Interest rate index | SOFR |
Spread on interest rate index (as a percent) | 1.65% |
Trust XI |  |
Junior subordinated interest deferrable debentures, major types of business trusts |  |
Junior subordinated deferrable interest debentures | $ 25,990,000 |
Interest rate (as a percent) | 7.28% |
Interest rate index | SOFR |
Spread on interest rate index (as a percent) | 1.62% |
Trust XII |  |
Junior subordinated interest deferrable debentures, major types of business trusts |  |
Junior subordinated deferrable interest debentures | $ 20,619,000 |
Interest rate (as a percent) | 7.09% |
Interest rate index | SOFR |
Spread on interest rate index (as a percent) | 1.45% |

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