Loans Receivable (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Forecast changes	$ (206.5)	$ 16.7
Certain Loans Acquired In Transfer Accounted For As Loans Accretable Yield Reclassifications From Nonaccretable Difference Forecast Changes, By Percentage	2.30%
Dealer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Forecast changes	$ (75.9)	0.5
Purchased Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Forecast changes	(130.6)	$ 16.2
Forecast Changes [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Forecast changes	(44.3)
COVID-19 Adjustment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Forecast changes	$ (162.2)