Other Operating Income - (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Components of Other Operating Income [Line Items]
Total Other Operating Income	$ 243.9	$ 194.0	$ 145.5
Loan Service Fees
Components of Other Operating Income [Line Items]
Total Other Operating Income	66.6	52.5	48.0
Banking Service Fees
Components of Other Operating Income [Line Items]
Total Other Operating Income	50.9	46.1	45.6
Other Income
Components of Other Operating Income [Line Items]
Total Other Operating Income	$ 126.4	$ 95.4	$ 51.9