Other Real Estate Owned (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Real Estate Acquired Through Foreclosure [Roll Forward]
Beginning balance	$ 2.5	$ 8.5
Additions	0.3	0.9
Valuation adjustments	0.0
Dispositions	(0.6)	(1.2)
Ending balance	2.2	$ 8.2
Carrying values of foreclosed residential real estate properties	0.0
Consumer mortgage loans collateralized by residential real estate property in the process of foreclosure	$ 0.0		$ 0.2