Accounts Payable and Accrued Expenses (Details) - Consolidated Entity Excluding Consolidated Funds - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Accounts Payable And Accrued Expenses [Line Items]
Accounts payable	$ 7.7	$ 9.0
Accrued expenses	26.1	36.8
Accrued interest payable	7.0	6.8
Other	0.7	1.7
Total accounts payable and accrued expenses	$ 41.5	$ 54.3