Income Taxes (Schedule Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Allowance for credit losses			$ 801.4	$ 128.3
Stock-based compensation			15.8	15.5
Deferred state net operating loss			4.3	3.6
Other, net			12.3	13.2
Total deferred tax assets			833.8	160.6
Valuation of Loans receivable			1,208.5	471.3
Deferred Loan origination costs			1.6	1.6
Other, net			14.7	10.2
Total deferred tax liabilities			1,224.8	483.1
Net deferred tax liability			$ 391.0	$ 322.5
Deferred tax asset valuation allowance, Increase (Decrease)	$ 3.4	$ 5.5