Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Balance Sheet Grouping, Financial Statement Captions
Carrying Value	$ 615.5	$ 420.9
Kudu Credit Facility
Balance Sheet Grouping, Financial Statement Captions
Carrying Value	253.5	218.2
Other Operations debt
Balance Sheet Grouping, Financial Statement Captions
Carrying Value	35.6
Fair Value | HG Global Senior Notes
Balance Sheet Grouping, Financial Statement Captions
Fair Value	146.1	0.0
Fair Value | Ark 2007 Notes
Balance Sheet Grouping, Financial Statement Captions
Fair Value	26.2	27.6
Fair Value | Ark 2021 Notes
Balance Sheet Grouping, Financial Statement Captions
Fair Value	149.4	162.8
Fair Value | Kudu Credit Facility
Balance Sheet Grouping, Financial Statement Captions
Fair Value	265.5	246.8
Fair Value | Other Operations debt
Balance Sheet Grouping, Financial Statement Captions
Fair Value	36.8	17.7
Carrying Value | HG Global Senior Notes
Balance Sheet Grouping, Financial Statement Captions
Carrying Value	146.4	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	150.0	155.9
Carrying Value | Kudu Credit Facility
Balance Sheet Grouping, Financial Statement Captions
Carrying Value	260.4	218.2
Carrying Value | Other Operations debt
Balance Sheet Grouping, Financial Statement Captions
Carrying Value	$ 35.6	$ 16.8