Leases - Schedule of Right-of-Use Assets and Lease Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Lessee, Lease, Description [Line Items]
ROU lease asset	$ 26.2	$ 28.1
Lease liability	$ 28.2	$ 30.0
Operating lease, weighted average incremental borrowing rate, percent	4.10%	4.00%
HG/BAM
Lessee, Lease, Description [Line Items]
ROU lease asset	$ 6.7	$ 7.6
Lease liability	7.2	8.1
Ark
Lessee, Lease, Description [Line Items]
ROU lease asset	7.3	7.0
Lease liability	7.3	7.0
Asset Management (Kudu)
Lessee, Lease, Description [Line Items]
ROU lease asset	6.1	6.4
Lease liability	6.9	7.1
Other Operations (1)
Lessee, Lease, Description [Line Items]
ROU lease asset	6.1	7.1
Lease liability	$ 6.8	$ 7.8