Fair Value Of Financial Instruments (Schedule Of Comparison Of The Carrying Value And Estimated Fair Value Of These Financial Instruments) (Details) - USD ($) $ in Millions		Dec. 31, 2017	Dec. 31, 2016
Assets, Fair Value Disclosure [Abstract]
Cash and cash equivalents	[1]	$ 8.2	$ 14.6
Restricted cash and cash equivalents	[1]	255.6	224.7
Restricted securities available for sale	[2]	46.1	45.3
Net investment in Loans receivable	[1]	4,741.5	3,955.9
Liabilities, Fair Value Disclosure [Abstract]
Revolving secured line of credit	[1]	13.9	0.0
Secured financing	[1]	2,527.6	2,072.0
Senior notes	[1]	569.4	560.5
Carrying Amount [Member]
Assets, Fair Value Disclosure [Abstract]
Cash and cash equivalents		8.2	14.6
Restricted cash and cash equivalents		255.6	224.7
Restricted securities available for sale		46.1	45.3
Net investment in Loans receivable		4,619.6	3,886.6
Liabilities, Fair Value Disclosure [Abstract]
Revolving secured line of credit		13.9	0.0
Secured financing		2,514.1	2,062.4
Senior notes		542.8	541.3
Estimated Fair Value [Member]
Assets, Fair Value Disclosure [Abstract]
Cash and cash equivalents		8.2	14.6
Restricted cash and cash equivalents		255.6	224.7
Restricted securities available for sale		46.1	45.3
Net investment in Loans receivable		4,741.5	3,955.9
Liabilities, Fair Value Disclosure [Abstract]
Revolving secured line of credit		13.9	0.0
Secured financing		2,527.6	2,072.0
Senior notes		$ 569.4	$ 560.5

[1] at amortized cost with fair value disclosed.

[2] Measured at fair value on a recurring basis.