Financial Instruments with Off-Balance Sheet Risk, Contingencies and Concentration of Credit Risk (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Standby Letters of Credit
Loss Contingencies [Line Items]
Commitments and obligations, liability outstanding	$ 27.4	$ 21.2
Commitments to Extend Credit
Loss Contingencies [Line Items]
Commitments and obligations, liability outstanding	$ 823.8	$ 867.2
Subsidiary | Snyder v Crusador Servicing Corporation Case
Loss Contingencies [Line Items]
Ownership percentage of subsidiary	80.00%