Commitments and Contingencies (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Related party mortgage originator (with flow mortgage loan purchase and sale agreement) [Member] | Non-Exchange Traded Equity Investment in Mortgage Originators [Member]
Other Commitments [Line Items]
Maximum guarantees	$ 25.0
Drawn down amount being guaranteed	17.3	$ 0.4
Residential mortgage loans
Other Commitments [Line Items]
Unfunded commitment	3.2	5.2
Corporate loan [Member]
Other Commitments [Line Items]
Unfunded commitment	$ 1.5	$ 1.9