Available for Sale Securities - Investments Pledged as Collateral to Secure Public Deposits and Securities Sold Under Agreements to Repurchase (Details) - Pledged as collateral - Public deposits - USD ($) $ in Millions	Sep. 30, 2023	Jun. 30, 2023
Financial Instruments Owned and Pledged as Collateral [Line Items]
Securities pledged as collateral	$ 261.0	$ 253.9
Asset backed securities
Financial Instruments Owned and Pledged as Collateral [Line Items]
Securities pledged as collateral	140.9	129.2
Collateralized Mortgage Obligations
Financial Instruments Owned and Pledged as Collateral [Line Items]
Securities pledged as collateral	91.8	94.8
US States and Political Subdivisions Debt Securities [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Securities pledged as collateral	25.2	26.5
Other Debt Obligations [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Carrying value of investment and MBS pledged as collateral to secure public deposits and securities sold under agreements to repurchase	$ 3.1	$ 3.4