Fair Value of Financial Instruments (Schedule of Assets and Liabilities, Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions		Jun. 30, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	[1]	$ 3.2	$ 7.7
Restricted cash and cash equivalents	[1]	408.8	410.0
Debt Securities, Available-for-sale	[2]	81.4	72.3
Loans receivable, net	[1]	7,274.0	6,767.9
Revolving secured lines of credit	[1]	168.9	30.9
Secured financing	[1]	3,742.9	3,581.9
Senior notes	[1]	773.7	759.0
Mortgage note	[1]	8.6	8.9
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	[1]	3.2	7.7
Restricted cash and cash equivalents	[1]	408.8	410.0
Debt Securities, Available-for-sale	[2]	65.4	58.7
Secured financing	[1]	2,942.8	2,781.8
Senior notes	[1]	773.7	759.0
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]	16.0	13.6
Revolving secured lines of credit	[1]	168.9	30.9
Secured financing	[1]	800.1	800.1
Mortgage note	[1]	8.6	8.9
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans receivable, net	[1]	$ 7,274.0	$ 6,767.9

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

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