Investment Securities - Pledged Securities (Details) - Asset Pledged as Collateral without Right - Deposits - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Investment Securities
Available-for-sale securities market value	$ 78.4	$ 83.4
Held-to-maturity securities market value	35.0	31.0
Debt securities available for sale amortized cost	84.9	91.0
Debt securities held-to-maturity amortized cost	$ 41.6	$ 37.7