Debt - Narrative (Details) € in Millions			1 Months Ended					3 Months Ended				6 Months Ended
	Apr. 29, 2022 USD ($)	Sep. 08, 2021 USD ($)	Jul. 31, 2023	Sep. 30, 2021 USD ($)	Aug. 31, 2021	Jul. 31, 2021	Mar. 31, 2007 USD ($)	Jun. 30, 2024 USD ($) credit_facility	Mar. 31, 2024 USD ($)	Jun. 30, 2023 USD ($)	Sep. 30, 2021 USD ($)	Jun. 30, 2024 USD ($) credit_facility	Dec. 31, 2023 USD ($)	Jun. 30, 2023 USD ($)	Jul. 31, 2024	Jun. 30, 2024 EUR (€) credit_facility	Jun. 28, 2024 USD ($)	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 (€)	Mar. 23, 2021 USD ($)
Debt Instrument
Repayments of notes												$ 34,100,000		$ 23,100,000
Interest Rate Cap | Subsidiary - HG Global
Debt Instrument
Notional amount																			$ 150,000,000
Ark 2007 Subordinated Notes | Junior Subordinated Debt
Debt Instrument
Face value							$ 30,000,000
Repayments of notes									$ 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 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				41,900,000	$ 42,700,000			€ 39.1
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	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%
Debt instrument, period for interest rate increase		10 years
Solvency capital requirement				120.00%
Debt to capital requirement				40.00%
Outstanding balance								70,000,000.0				$ 70,000,000.0	70,000,000.0
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																					$ 125,000,000
Letters of credit outstanding								111,500,000				111,500,000
Pledged collateral								137,600,000				137,600,000
Lloyds LOC Facility | Line of Credit | Letter of Credit
Debt Instrument
Total commitment under revolving credit facility																		$ 100,000,000
Letters of credit outstanding								35,500,000				35,500,000
Pledged collateral								65,400,000				$ 65,400,000
HG Global Senior Notes | Senior Notes
Debt Instrument
Face value	$ 150,000,000
Additional interest rate												1.00%
Outstanding balance								150,000,000.0				$ 150,000,000.0	150,000,000.0
Stated margin	6.00%
Anniversary of funding date	5 years
Annual payments																				$ 15,000,000
Interest accrued multiplier																			8
Interest reserve account, maximum																			$ 29,300,000
Interest reserve account								29,400,000				29,400,000	30,400,000
HG Global Senior Notes | Senior Notes | Secured Overnight Financing Rate (SOFR)
Debt Instrument
Basis spread on variable rate	0.26%
Kudu Credit Facility | Secured Debt
Debt Instrument
Face value																	$ 350,000,000								$ 300,000,000
Basis spread on variable rate			0.26%											0.25%
Repayments of notes								0		$ 0		0		$ 16,900,000
Outstanding balance								210,300,000				210,300,000	210,300,000
Stated margin			4.30%							4.30%				4.30%
Restricted cash								$ 15,000,000				$ 15,000,000	$ 14,900,000
Debt covenant, maximum loan to value percent								22.70%				22.70%				22.70%
Percentage of borrowing base								35.00%				35.00%				35.00%
Kudu Credit Facility | Secured Debt | Subsequent Event
Debt Instrument
Stated margin															4.45%
Kudu Credit Facility | Secured Debt | Debt Covenant, Period 1
Debt Instrument
Debt covenant, loan to value percent								50.00%				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%				40.00%
Kudu Credit Facility | Secured Debt | Debt Covenant, Period 3
Debt Instrument
Debt covenant, loan to value percent								25.00%				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%				15.00%
Kudu Credit Facility | Secured Debt | Debt Covenant, Period 5
Debt Instrument
Debt covenant, loan to value percent								0.00%				0.00%				0.00%
Kudu Credit Facility | Secured Debt | Secured Overnight Financing Rate (SOFR)
Debt Instrument
Basis spread on variable rate													0.26%
Other Operations debt | Secured Debt
Debt Instrument
Outstanding balance								$ 25,200,000				$ 25,200,000	$ 28,900,000
Secured credit facilities | credit_facility								4				4				4