Fair Value of Financial Instruments (Schedule of Comparison of the Carrying Value and Estimated Fair Value of Financial Instruments) (Details) - USD ($) $ in Millions		Sep. 30, 2016	Dec. 31, 2015
Assets
Cash and cash equivalents		$ 5.7	$ 6.3
Restricted cash and cash equivalents		232.8	167.4
Restricted securities available for sale		47.0	48.3
Net investment in Loans receivable		3,820.8	3,126.3
Liabilities
Revolving secured line of credit		85.2	57.7
Secured financing (1)		1,901.0	1,471.9
Senior notes		559.4	549.6
Carrying Amount [Member]
Assets
Cash and cash equivalents		5.7	6.3
Restricted cash and cash equivalents		232.8	167.4
Restricted securities available for sale		47.0	48.3
Net investment in Loans receivable		3,764.4	3,101.5
Liabilities
Revolving secured line of credit		85.2	57.7
Secured financing (1)	[1]	1,884.2	1,470.1
Senior notes	[1]	541.0	540.0
Estimated Fair Value [Member]
Assets
Cash and cash equivalents		5.7	6.3
Restricted cash and cash equivalents		232.8	167.4
Restricted securities available for sale		47.0	48.3
Net investment in Loans receivable		3,820.8	3,126.3
Liabilities
Revolving secured line of credit		85.2	57.7
Secured financing (1)	[1]	1,901.0	1,471.9
Senior notes	[1]	$ 559.4	$ 549.6

[1] Prior year carrying amounts have been reclassified to reflect the adoption of ASU 2015-03, as amended by ASU No. 2015-15, which resulted in a reclassification of certain deferred debt issuance costs from other assets to secured financing and senior notes.