Allowance for Credit Losses - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Allowance for Credit Losses
Available for sale debt securities past due	$ 0.0		$ 0.0
Provision (reversal) in allowance on individually evaluated loans	(0.2)	$ 5.2	(1.2)	$ 5.6
Provision (reversal) in allowance on collectively evaluated loans	(0.5)	(11.0)	5.9	(45.2)
Net charge-offs	$ 2.7		$ 4.2
Net recoveries		$ 0.1		$ 0.1