Fair Value of Financial Instruments (Schedule of Assets and Liabilities, Measured at Fair Value on a Recurring Basis) - USD ($) $ in Millions		Mar. 31, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	[1]	$ 17.6	$ 23.3
Restricted cash and cash equivalents	[1]	481.1	410.9
Debt Securities, Available-for-sale	[2]	62.4	62.1
Loans receivable, net	[1]	6,543.7	6,580.4
Revolving secured line of credit	[1]	104.7	2.6
Secured financing	[1]	3,775.8	3,832.1
Senior notes	[1]	812.7	825.8
Mortgage note	[1]	9.4	9.7
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	[1]	17.6	23.3
Restricted cash and cash equivalents	[1]	481.1	410.9
Debt Securities, Available-for-sale	[2]	51.4	49.0
Senior notes	[1]	812.7	825.8
Mortgage note	[1]	0.0	0.0
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	[2]	11.0	13.1
Revolving secured line of credit	[1]	104.7	2.6
Secured financing	[1]	3,775.8	3,832.1
Mortgage note	[1]	9.4	9.7
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans receivable, net	[1]	$ 6,543.7	$ 6,580.4

[1] Measured at amortized cost with fair value disclosed.

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