Mortgage Servicing Rights - Narrative (Details) - Mortgage loans - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value [Abstract]
Mortgage servicing rights, fair value	$ 38.8	$ 37.4
Servicing asset at fair value, assumptions used to estimate fair value, weighted average life	7 years 9 months 18 days	7 years 7 months 6 days
Impairment reversals	$ 0.0	$ (3.4)	$ (6.9)
Permanent impairment charged against carrying value	$ 0.0
Minimum
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value [Abstract]
Servicing assets at fair value, assumptions used to estimate fair value, discount rate	11.90%	11.80%
Servicing assets at fair value, assumptions used to estimate fair value, prepayment speed	0.40%	0.50%
Maximum [Member]
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value [Abstract]
Servicing assets at fair value, assumptions used to estimate fair value, discount rate	12.80%	13.50%
Servicing assets at fair value, assumptions used to estimate fair value, prepayment speed	1.60%	3.40%