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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Face (par) amount of debt instrument at time of issuance.

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Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

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Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

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Amount of cash outflow for payment of an obligation from a lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

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Fair value of financial instrument held by the entity for its own account (proprietary securities) for trading or investment purposes that are carried at fair value and pledged to counterparties as collateral for financing transactions.

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Debt - Narrative (Details) € in Millions, £ in Millions					1 Months Ended				3 Months Ended
Debt - Narrative (Details) € in Millions, £ in Millions	Sep. 08, 2021 USD ($)	Jun. 02, 2021 USD ($)	Jun. 01, 2021	Apr. 07, 2020	Sep. 30, 2021 USD ($)	Aug. 31, 2021	Jul. 31, 2021	Mar. 31, 2007 USD ($)	Mar. 31, 2022 USD ($) credit_facility	Mar. 31, 2022 GBP (£)	Mar. 31, 2021 USD ($)	Mar. 31, 2022 EUR (€) credit_facility	Dec. 31, 2021 USD ($)	Aug. 11, 2021 USD ($)	Jul. 13, 2021 USD ($)	Jul. 13, 2021 EUR (€)	Dec. 31, 2020 USD ($)	Jun. 15, 2018 USD ($)
Debt Instrument
Debt									$ 690,900,000				$ 693,000,000.0
Debt covenant, maximum loan to value percent, period one									50.00%			50.00%
Debt covenant, maximum loan to value percent, period two									40.00%			40.00%
Debt covenant, maximum loan to value percent, period three									25.00%			25.00%
Debt covenant, maximum loan to value percent, period four									15.00%			15.00%
Debt covenant, maximum loan to value percent, period five									0.00%			0.00%
Debt covenant, maximum loan to value percent									33.00%			33.00%
Draw down of debt and revolving line of credit									$ 15,000,000.0		$ 105,300,000
Short-term investments
Debt Instrument
Investments pledged as collateral									$ 50,000,000				50,000,000
Other
Debt Instrument
Secured credit facilities \| credit_facility									3			3
Specialty Insurance Distribution (NSM)
Debt Instrument
Debt									$ 270,600,000				272,100,000
Specialty Insurance Distribution (NSM) \| Interest Rate Swap
Debt Instrument
Interest income									2,400,000
Specialty Insurance Distribution (NSM) \| Interest Rate Swap \| Term loan - hedged
Debt Instrument
Interest income									(600,000)		(600,000)
Specialty Insurance Distribution (NSM) \| Interest Rate Swap \| Term loan - unhedged
Debt Instrument
Interest income									3,500,000
Ark
Debt Instrument
Debt									184,800,000				185,900,000
Unsecured Subordinated Debt \| Group Ark Insurance Limited
Debt Instrument
Borrowings											157,800,000
Unsecured Subordinated Debt \| Group Ark Insurance Limited \| Ark
Debt Instrument
Notes issued					$ 163,300,000
Ark 2007 Subordinated Notes, carrying value \| Ark Subordinated Debt
Debt Instrument
Outstanding balance									30,000,000.0				30,000,000.0
Ark 2007 Subordinated Notes, carrying value \| Junior Notes \| Ark
Debt Instrument
Amount borrowed								$ 30,000,000
Debt									30,000,000
Ark 2007 Subordinated Notes, carrying value \| Junior Notes \| USD-LIBOR \| Ark
Debt Instrument
Basis spread on variable rate								4.60%
Ark 2021 Notes Tranche 1
Debt Instrument
Outstanding balance \| €												€ 39.1
Ark 2021 Notes Tranche 1 \| Ark Subordinated Debt
Debt Instrument
Outstanding balance									42,900,000				44,200,000
Ark 2021 Notes Tranche 1 \| Unsecured Subordinated Debt \| Group Ark Insurance Limited
Debt Instrument
Notes issued															$ 46,300,000	€ 39.1
Ark 2021 Notes Tranche 1 \| Unsecured Subordinated Debt \| Group Ark Insurance Limited \| EURIBOR
Debt Instrument
Basis spread on variable rate							5.75%
Ark 2021 Notes Tranche 2 \| Ark Subordinated Debt
Debt Instrument
Outstanding balance									47,000,000				47,000,000.0
Ark 2021 Notes Tranche 2 \| Unsecured Subordinated Debt \| Group Ark Insurance Limited
Debt Instrument
Notes issued														$ 47,000,000
Ark 2021 Notes Tranche 2 \| Unsecured Subordinated Debt \| Group Ark Insurance Limited \| USD-LIBOR
Debt Instrument
Basis spread on variable rate						5.75%
Ark 2021 Notes Tranche 3 \| Ark Subordinated Debt
Debt Instrument
Outstanding balance									70,000,000.0				70,000,000.0
Ark 2021 Notes Tranche 3 \| Unsecured Subordinated Debt \| Group Ark Insurance Limited
Debt Instrument
Notes issued	$ 70,000,000
Additional interest rate	1.00%
Solvency capital requirement					120.00%
Debt to capital requirement					40.00%
Ark 2021 Notes Tranche 3 \| Unsecured Subordinated Debt \| Group Ark Insurance Limited \| USD-LIBOR
Debt Instrument
Basis spread on variable rate	6.10%
ING LOC Facility \| Secured Debt \| Ark \| Letter of Credit \| Uncollateralized
Debt Instrument
Total commitment under revolving credit facility													50,000,000
Citibank LOC Facility \| Short-term investments
Debt Instrument
Investments pledged as collateral									50,000,000
Citibank LOC Facility \| Secured Debt
Debt Instrument
Line of credit									36,200,000
Citibank LOC Facility \| Secured Debt \| Ark \| Letter of Credit \| Collateral Pledged
Debt Instrument
Total commitment under revolving credit facility													100,000,000
Ark \| Ark Subordinated Debt
Debt Instrument
Debt									184,800,000				185,900,000
NSM Bank Facility \| Specialty Insurance Distribution (NSM)
Debt Instrument
Debt									$ 275,900,000		277,300,000		277,600,000				$ 277,400,000
Percentage of discounted future cash flows									10.00%	10.00%
NSM Bank Facility \| Term Loan
Debt Instrument
Debt									$ 270,000,000.0				271,200,000
Outstanding balance									275,900,000				277,600,000
NSM Bank Facility \| Term Loan \| Specialty Insurance Distribution (NSM)
Debt Instrument
Amount borrowed		$ 50,000,000							271,900,000
Borrowings									0		0
Floor rate				1.25%
NSM Bank Facility \| Term Loan \| Specialty Insurance Distribution (NSM) \| Interest Rate Swap
Debt Instrument
Total commitment under revolving credit facility																		$ 151,000,000.0
Hedged liability, fair value																		$ 151,000,000
NSM Bank Facility \| Term Loan \| Specialty Insurance Distribution (NSM) \| USD-LIBOR \| Minimum
Debt Instrument
Basis spread on variable rate		4.50%	5.50%
NSM Bank Facility \| Term Loan \| Specialty Insurance Distribution (NSM) \| USD-LIBOR \| Maximum
Debt Instrument
Basis spread on variable rate		5.00%	6.00%
NSM Bank Facility \| Term Loan \| Specialty Insurance Distribution (NSM) \| GBP-LIBOR \| Minimum
Debt Instrument
Basis spread on variable rate		5.00%	6.00%
NSM Bank Facility \| Term Loan \| Specialty Insurance Distribution (NSM) \| GBP-LIBOR \| Maximum
Debt Instrument
Basis spread on variable rate		5.50%	6.50%
NSM Bank Facility \| GBP Term Loan \| Specialty Insurance Distribution (NSM)
Debt Instrument
Borrowings									55,100,000	£ 41.8
NSM Bank Facility \| Revolving credit loan \| Specialty Insurance Distribution (NSM)
Debt Instrument
Amount borrowed									4,000,000
Borrowings									13,000,000.0		0
Total commitment under revolving credit facility		$ 40,000,000
Other NSM
Debt Instrument
Debt									600,000				900,000
Other NSM \| Term Loan \| Specialty Insurance Distribution (NSM)
Debt Instrument
Debt									600,000
Kudu Bank Facility \| Kudu
Debt Instrument
Total commitment under revolving credit facility									300,000,000
Kudu Bank Facility \| Term Loan \| Kudu
Debt Instrument
Debt									0		0		$ 0				$ 89,200,000
Borrowings									$ 0		3,000,000.0
Percentage of borrowing base									35.00%			35.00%
Remaining borrowing capacity under revolving credit facility									$ 34,200,000
Kudu Bank Facility \| Revolving credit loan \| Kudu
Debt Instrument
Loss on debt extinguishment									4,100,000
Kudu Bank Facility \| Line of Credit \| Kudu
Debt Instrument
Interest reserve									4,500,000
First Credit Facility \| Other
Debt Instrument
Total commitment under revolving credit facility									16,300,000
First Credit Facility \| Term Loan \| Other
Debt Instrument
Total commitment under revolving credit facility									11,300,000
First Credit Facility \| Revolving credit loan \| Other
Debt Instrument
Total commitment under revolving credit facility									2,000,000
First Credit Facility \| Delayed Draw Term Loans \| Other
Debt Instrument
Total commitment under revolving credit facility									3,000,000
Second Credit Facility \| Other
Debt Instrument
Total commitment under revolving credit facility									15,000,000
Second Credit Facility \| Term Loan \| Other
Debt Instrument
Total commitment under revolving credit facility									9,000,000
Second Credit Facility \| Revolving credit loan \| Other
Debt Instrument
Total commitment under revolving credit facility									2,000,000
Second Credit Facility \| Delayed Draw Term Loans \| Other
Debt Instrument
Total commitment under revolving credit facility									4,000,000
Third Credit Facility \| Other
Debt Instrument
Total commitment under revolving credit facility									8,000,000
Third Credit Facility \| Term Loan \| Other
Debt Instrument
Outstanding balance									17,800,000		17,500,000
Repayments of lines of credit									1,300,000		200,000
Third Credit Facility \| Revolving credit loan \| Other
Debt Instrument
Draw down of debt and revolving line of credit									$ 2,000,000		$ 900,000