Financial Instruments with Off-Balance Sheet Risk (Details) $ in Millions	Jun. 30, 2019 USD ($)
Entity Information [Line Items]
Credit extension commitments	$ 2,727.0
Unused Credit Card Lines
Entity Information [Line Items]
Credit extension commitments	749.1
Credit extension commitments beyond one year	1,162.4
Standby Letters of Credit
Entity Information [Line Items]
Credit extension commitments	$ 56.8