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Derivatives - NSM Interest Rate Swap and Cap (Details)		3 Months Ended
	Aug. 18, 2020	Mar. 31, 2021 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)	Jun. 04, 2020 USD ($)	Jun. 04, 2020 GBP (£)	Apr. 07, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jun. 15, 2018 USD ($)
Derivative [Line Items]
Total commitment under revolving credit facility				$ 234,000,000.0				$ 291,400,000
Debt		$ 429,700,000			$ 376,400,000
NSM Bank Facility | Term Loan
Derivative [Line Items]
Debt		271,500,000			271,300,000
Specialty Insurance Distribution (NSM)
Derivative [Line Items]
Debt		$ 272,700,000			272,600,000
Weighted Average Interest rate		8.50%		7.60%
Specialty Insurance Distribution (NSM) | Term loan - hedged
Derivative [Line Items]
Weighted Average Interest rate		9.20%		8.10%
Specialty Insurance Distribution (NSM) | Interest Rate Swap
Derivative [Line Items]
Derivative, fixed interest rate										2.97%
Derivative, variable interest rate		1.00%
Interest expense, net		$ 600,000		$ 500,000
Derivative, fair value, net		7,200,000			8,200,000
Change in fair value of derivative instruments		1,000,000.0		(3,200,000)
Specialty Insurance Distribution (NSM) | Interest Rate Cap
Derivative [Line Items]
Derivative, fair value, net		100,000			100,000
Change in fair value of derivative instruments		$ 100,000
Premiums paid			$ 100,000
GBP-LIBOR rate		0.09%
Specialty Insurance Distribution (NSM) | Interest Rate Cap | GBP-LIBOR
Derivative [Line Items]
Derivative, cap interest rate		1.25%
Specialty Insurance Distribution (NSM) | NSM Bank Facility
Derivative [Line Items]
Debt		$ 277,300,000		220,700,000	$ 277,400,000				$ 221,300,000
Amount borrowed		277,300,000
Specialty Insurance Distribution (NSM) | NSM Bank Facility | Term Loan
Derivative [Line Items]
Amount borrowed				$ 224,000,000.0				$ 276,400,000
Specialty Insurance Distribution (NSM) | NSM Bank Facility | Interest Rate Swap | Term Loan
Derivative [Line Items]
Total commitment under revolving credit facility										$ 151,000,000.0
Specialty Insurance Distribution (NSM) | NSM Bank Facility | Interest Rate Swap | Term Loan | Term loan - hedged
Derivative [Line Items]
Debt		$ 147,200,000
Specialty Insurance Distribution (NSM) | NSM Bank Facility | Interest Rate Cap
Derivative [Line Items]
Debt instrument, term extension	1 year
Specialty Insurance Distribution (NSM) | NSM Bank Facility | Interest Rate Cap | United Kingdom, Pounds
Derivative [Line Items]
Derivative, Notional Amount | £							£ 42,500,000
Specialty Insurance Distribution (NSM) | NSM Bank Facility | Interest Rate Cap | United States of America, Dollars
Derivative [Line Items]
Derivative, Notional Amount						$ 52,400,000

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- Definition

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

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- Definition

Weighted average interest rate of debt outstanding.

+ References

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- Definition

Cap rate on an interest rate derivative such as an interest rate cap or collar. If market rates exceed the cap rate, a payment or receipt is triggered on the contract.

+ References

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The premium (cost) of a hedge, expensed during the period.

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- Definition

Fair value of the assets less the liabilities of a derivative or group of derivatives.

+ References

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- Definition

Fixed interest rate related to the interest rate derivative.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Nominal or face amount used to calculate payment on derivative.

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- Definition

Variable interest rate in effect as of the balance sheet date related to the interest rate derivative.

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- Definition

The net amount of operating interest income (expense).

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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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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount after tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Debt Instrument, Term Extension

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LIBOR rate

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