Securities (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Allowance for credit loss	$ 0.0
Accrued interest receivable on available-for-sale debt securities	4.6		$ 3.7
Proceeds from Sale of Debt Securities, Available-for-sale	0.0	$ 0.0
Held-to-maturity Securities
Specific reserve for outstanding balance of financing receivable in active forbearance	1.1		1.1
Accrued interest receivable on held-to-maturity securities	$ 0.1		$ 0.1