Junior Subordinated Interest Deferrable Debentures (Details)	9 Months Ended
	Sep. 30, 2023 USD ($) item	Apr. 07, 2023 USD ($)	Dec. 31, 2022 USD ($)
Junior subordinated interest deferrable debentures, major types of business trusts
Number of statutory business trusts issuing trust preferred securities | item	4
Junior subordinated deferrable interest debentures	$ 108,868,000		$ 134,642,000
Maximum number of consecutive quarterly period available for deferral of interest payment on Trusts IX, X, XI and XII | item	20
Percentage of capital securities issued by trust qualifying as Tier I capital, maximum	25.00%
Percentage of capital securities issued by trust qualifying as Tier II capital, minimum	25.00%
Capital securities issued by the trust, qualifying as Tier I capital	$ 108,868,000		$ 134,642,000
Trust VIII
Junior subordinated interest deferrable debentures, major types of business trusts
Junior subordinated deferrable interest debentures		$ 25,000,000