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Investments - Additional Information (Detail) | 3 Months Ended |
--- | --- | ---
Mar. 31, 2024 USD ($) ParntershipInvestments Entity | Dec. 31, 2023 USD ($)
Schedule Of Available For Sale Securities [Line Items] |  |
Investments in a single issuer as a percentage of shareholders' equity | 2.00% | 2.10%
Number of limited partnership investments | ParntershipInvestments | 3 |
Fixed maturity securities with market value | $ 0 | $ 0
Investments in insurance enhanced bonds | $ 4,900,000 |
Insurance enhanced bonds as a percentage of total cash and invested assets | 0.30% |
Investments in collateralized mortgage obligations, commercial mortgage-backed securities and taxable municipal bonds | $ 4,900,000 |
Equity securities, at fair value | 17,045,000 | 16,508,000
Limited partnership investments with carrying value of fair value | $ 34,000,000 | 38,200,000
Variable Interest Entity, Not Primary Beneficiary |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Number of VIE's | Entity | 2 |
Ownership interest exceeds respective investments | 3.00% |
One of the Company's variable interest VIE's, invests in distressed securities and assets |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Significant variable interest in carrying value of the non-consolidated VIE | $ 4,000,000 | 4,000,000
Variable interest entities, maximum exposure to loss | 18,200,000 | 18,300,000
Second VIE that invests in REIT qualifying assets |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Significant variable interest in carrying value of the non-consolidated VIE | 8,600,000 | 8,200,000
Assured Guaranty Corporation |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Investments in collateralized mortgage obligations, commercial mortgage-backed securities and taxable municipal bonds | 3,700,000 |
Ambac Financial Group |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Investments in collateralized mortgage obligations, commercial mortgage-backed securities and taxable municipal bonds | 1,200,000 |
Other Assets |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Accrued interest receivable related to fixed maturities | 5,400,000 | 7,500,000
Preferred Stock |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Equity securities, at fair value | 17,000,000 | $ 16,500,000
U.S. Treasuries |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Gross unrealized losses | 2,843,000 |
Obligations of States and Political Subdivisions |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Gross unrealized losses | 1,188,000 |
Mortgage Backed Securities |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Gross unrealized losses | 4,144,000 |
Asset-backed Securities |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Gross unrealized losses | $ 4,441,000 |
Weighted average credit enhancement | 37.00% |
Commercial Mortgage-Backed Securities |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Gross unrealized losses | $ 4,271,000 |
Weighted average credit enhancement | 48.50% |
Corporate Bonds |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Gross unrealized losses | $ 5,891,000 |
Foreign Corporate Bonds |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Gross unrealized losses | $ 3,325,000 |

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