Debt - Narrative (Details) € in Millions				1 Months Ended				3 Months Ended	6 Months Ended	9 Months Ended
	Jul. 01, 2023	Apr. 29, 2022 USD ($)	Sep. 08, 2021 USD ($)	Sep. 30, 2021 USD ($)	Aug. 31, 2021	Jul. 31, 2021	Mar. 31, 2007 USD ($)	Sep. 30, 2021 USD ($)	Jun. 30, 2023	Sep. 30, 2023 USD ($) credit_facility	Sep. 30, 2023 EUR (€) credit_facility	Dec. 31, 2022 USD ($)	Sep. 30, 2022 USD ($)	Jun. 16, 2022 USD ($)	Apr. 30, 2022 USD ($)	Dec. 31, 2021 USD ($) letterOfCredit	Aug. 11, 2021 USD ($)	Jul. 13, 2021 USD ($)	Jul. 13, 2021 EUR (€)
Interest Rate Cap | Subsidiary - HG Global
Debt Instrument
Notional amount														$ 150,000,000
HG Global Senior Notes | Senior Notes
Debt Instrument
Face value		$ 150,000,000
Anniversary of funding date		5 years
Annual payments															$ 15,000,000
Interest accrued multiplier														8
Interest reserve account, maximum														$ 29,200,000
Interest reserve account										$ 29,900,000		$ 31,200,000
Additional interest rate										1.00%
Outstanding balance										$ 150,000,000.0		150,000,000.0
HG Global Senior Notes | Senior Notes | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument
Basis spread on variable rate		6.30%
Ark 2007 Subordinated Notes | Junior Subordinated Debt
Debt Instrument
Face value							$ 30,000,000
Outstanding balance										30,000,000
Ark 2007 Subordinated Notes | Junior Subordinated Debt | London Interbank Offered Rate (LIBOR)
Debt Instrument
Basis spread on variable rate							4.60%
Ark 2007 Subordinated Notes | Subordinated Debt
Debt Instrument
Outstanding balance										30,000,000.0		30,000,000.0
Ark 2021 Subordinated Notes | Subordinated Debt
Debt Instrument
Face value				$ 163,300,000				$ 163,300,000
Proceeds from debt, net of debt issuance costs								$ 157,800,000
Ark 2021 Subordinated Notes Tranche 1 | Subordinated Debt
Debt Instrument
Face value																		$ 46,300,000	€ 39.1
Outstanding balance										41,900,000	€ 39.1	41,300,000
Ark 2021 Subordinated Notes Tranche 1 | Subordinated Debt | Euro Interbank Offered Rate (EURIBOR)
Debt Instrument
Basis spread on variable rate						5.75%
Ark 2021 Subordinated Notes Tranche 2 | Subordinated Debt
Debt Instrument
Face value																	$ 47,000,000
Outstanding balance										$ 47,000,000.0		47,000,000.0
Ark 2021 Subordinated Notes Tranche 2 | Subordinated Debt | London Interbank Offered Rate (LIBOR)
Debt Instrument
Basis spread on variable rate					5.75%
Ark 2021 Subordinated Notes Tranche 3 | Subordinated Debt
Debt Instrument
Face value			$ 70,000,000
Additional interest rate										1.00%
Outstanding balance										$ 70,000,000.0		70,000,000.0
Solvency capital requirement				120.00%
Debt to capital requirement				40.00%
Ark 2021 Subordinated Notes Tranche 3 | Subordinated Debt | London Interbank Offered Rate (LIBOR)
Debt Instrument
Basis spread on variable rate			6.10%
ING LOC Facility | Line of Credit | Letter of Credit
Debt Instrument
Number of letter of credit agreements | letterOfCredit																2
Total commitment under revolving credit facility																$ 50,000,000
Citibank LOC Facility | Line of Credit | Letter of Credit
Debt Instrument
Total commitment under revolving credit facility																$ 100,000,000
Letters of credit outstanding										93,200,000
Pledged collateral										108,600,000
Lloyds LOC Facility | Line of Credit | Letter of Credit
Debt Instrument
Total commitment under revolving credit facility													$ 50,000,000
Letters of credit outstanding										25,900,000
Pledged collateral										38,600,000
Kudu Credit Facility | Secured Debt
Debt Instrument
Face value										300,000,000
Interest reserve account										14,100,000
Outstanding balance										$ 210,300,000		215,200,000
Stated margin	4.30%								4.30%
Restricted cash												12,200,000
Debt covenant, maximum loan to value percent										27.90%	27.90%
Percentage of borrowing base										35.00%	35.00%
Remaining borrowing capacity under revolving credit facility										$ 74,100,000
Kudu Credit Facility | Secured Debt | Debt Covenant, Period 1
Debt Instrument
Debt covenant, loan to value percent										50.00%	50.00%
Kudu Credit Facility | Secured Debt | Debt Covenant, Period 2
Debt Instrument
Debt covenant, loan to value percent										40.00%	40.00%
Kudu Credit Facility | Secured Debt | Debt Covenant, Period 3
Debt Instrument
Debt covenant, loan to value percent										25.00%	25.00%
Kudu Credit Facility | Secured Debt | Debt Covenant, Period 4
Debt Instrument
Debt covenant, loan to value percent										15.00%	15.00%
Kudu Credit Facility | Secured Debt | Debt Covenant, Period 5
Debt Instrument
Debt covenant, loan to value percent										0.00%	0.00%
Kudu Credit Facility | Secured Debt | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument
Basis spread on variable rate	0.26%
Kudu Credit Facility | Secured Debt | London Interbank Offered Rate (LIBOR)
Debt Instrument
Basis spread on variable rate									0.25%
Other Operations debt | Secured Debt
Debt Instrument
Outstanding balance										$ 30,100,000		$ 37,400,000
Secured credit facilities | credit_facility										4	4