Securities Sold Under Agreements to Repurchase - Schedule of Assets and Liabilities Subject to an Enforceable Master Netting Arrangement or Repurchase Agreements (Parenthetical) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Interest Rate Swap Agreements
Offsetting Assets And Liabilities [Line Items]
Fair value of investment securities pledged	$ 58.3	$ 7.9
Private Institutions
Offsetting Assets And Liabilities [Line Items]
Fair value of investment securities pledged	523.4	635.2
Government Entities
Offsetting Assets And Liabilities [Line Items]
Fair value of investment securities pledged	$ 1.3	$ 2.5