Fair Value Disclosure (Details 3) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Carrying Amount [Member]
Assets
Investment Funds	$ 0.6		$ 0.6		$ 0.6
Loans	0.2		0.2		6.2
Liabilities
Recourse fixed rate debt	3,864.6		3,864.6		3,858.5
Recourse floating rate debt	425.0		425.0		417.8
Estimate of Fair Value Measurement [Member]
Assets
Investment Funds	1.2		1.2		1.2
Loans	0.2		0.2		6.2
Liabilities
Recourse fixed rate debt	3,977.6		3,977.6		3,852.6
Recourse floating rate debt	429.4		429.4		$ 412.2
Not Designated as Hedging Instrument [Member] | Other Expense [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net	$ (2.0)	$ 2.2	$ 4.1	$ (0.1)