Debt - Narrative (Details) € in Millions			1 Months Ended				3 Months Ended	6 Months Ended		12 Months Ended
	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 ($)	Dec. 31, 2023 USD ($) credit_facility	Jun. 30, 2023	Dec. 31, 2023 USD ($) credit_facility	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($) letterOfCredit	Dec. 31, 2023 EUR (€) credit_facility	Sep. 30, 2022 USD ($)	Jun. 16, 2022 USD ($)	Aug. 11, 2021 USD ($)	Jul. 13, 2021 USD ($)	Jul. 13, 2021 EUR (€)
Debt Instrument
Outstanding balance								$ 578,900,000		$ 578,900,000
Interest expense										62,700,000	$ 40,300,000	$ 20,500,000
Interest paid										42,200,000	30,500,000	$ 13,900,000
Interest Rate Cap | Subsidiary - HG Global
Debt Instrument
Notational amount															$ 150,000,000
HG Global Senior Notes | Senior Notes
Debt Instrument
Long-term line of credit	$ 150,000,000
Interest rate	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								30,400,000		$ 30,400,000	31,200,000
Additional interest rate										1.00%
Outstanding balance								150,000,000		$ 150,000,000	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	0.26%
Ark 2007 Subordinated Notes | Junior Subordinated Debt
Debt Instrument
Long-term line of credit						$ 30,000,000
Outstanding balance								30,000,000		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	30,000,000.0
Ark 2021 Subordinated Notes | Subordinated Debt
Debt Instrument
Long-term line of credit			$ 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
Long-term line of credit																	$ 46,300,000	€ 39.1
Outstanding balance								42,700,000		42,700,000	41,300,000		€ 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
Long-term line of credit																$ 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
Long-term line of credit		$ 70,000,000
Additional interest rate										1.00%
Outstanding balance								70,000,000		$ 70,000,000	70,000,000.0
Debt instrument, period for interest rate increase		10 years
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												$ 125,000,000
Letters of credit outstanding								106,500,000		106,500,000
Pledged collateral								134,800,000		134,800,000
Lloyds LOC Facility | Line of Credit | Letter of Credit
Debt Instrument
Total commitment under revolving credit facility														$ 100,000,000
Letters of credit outstanding								28,600,000		28,600,000
Pledged collateral								64,100,000		64,100,000
Kudu Credit Facility | Secured Debt
Debt Instrument
Long-term line of credit								$ 300,000,000		$ 300,000,000
Interest rate								4.30%	4.30%	4.30%			4.30%
Interest reserve account								$ 14,900,000		$ 14,900,000
Outstanding balance								$ 210,300,000		$ 210,300,000	215,200,000
Restricted cash											12,200,000
Debt covenant, maximum loan to value percent								25.00%		25.00%			25.00%
Percentage of borrowing base								35.00%		35.00%			35.00%
Remaining borrowing capacity under revolving credit facility								$ 89,700,000		$ 89,700,000
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) 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								$ 28,900,000		$ 28,900,000	$ 37,400,000
Secured credit facilities | credit_facility								4		4			4