Mortgage Banking Derivatives (Details) - Mortgage banking derivatives - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Derivative asset, notional amount	$ 1.2	$ 109.1	$ 1.2	$ 109.1	$ 367.7
Net loss relating to mortgage banking derivative instruments	$ 0.0	$ 1.3	$ 0.0	$ 1.3
Other Assets
Derivatives, Fair Value [Line Items]
Derivative asset					$ 5.2