Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Balance Sheet Grouping, Financial Statement Captions
Carrying Value	$ 618.1	$ 420.9
Kudu Credit Facility
Balance Sheet Grouping, Financial Statement Captions
Carrying Value	253.3	218.2
Other Operations debt
Balance Sheet Grouping, Financial Statement Captions
Carrying Value	35.0
Fair Value | HG Global Senior Notes
Balance Sheet Grouping, Financial Statement Captions
Fair Value	144.8	0.0
Fair Value | Ark 2007 Notes
Balance Sheet Grouping, Financial Statement Captions
Fair Value	25.9	27.6
Fair Value | Ark 2021 Notes
Balance Sheet Grouping, Financial Statement Captions
Fair Value	149.8	162.8
Fair Value | Kudu Credit Facility
Balance Sheet Grouping, Financial Statement Captions
Fair Value	264.2	246.8
Fair Value | Other Operations debt
Balance Sheet Grouping, Financial Statement Captions
Fair Value	35.4	17.7
Carrying Value | HG Global Senior Notes
Balance Sheet Grouping, Financial Statement Captions
Carrying Value	146.3	0.0
Carrying Value | Ark 2007 Notes
Balance Sheet Grouping, Financial Statement Captions
Carrying Value	30.0	30.0
Carrying Value | Ark 2021 Notes
Balance Sheet Grouping, Financial Statement Captions
Carrying Value	153.5	155.9
Carrying Value | Kudu Credit Facility
Balance Sheet Grouping, Financial Statement Captions
Carrying Value	253.3	218.2
Carrying Value | Other Operations debt
Balance Sheet Grouping, Financial Statement Captions
Carrying Value	$ 35.0	$ 16.8