v3.25.2
Investments - Additional Information (Detail)
 6 Months Ended
Jun. 30, 2025
USD ($)
Entity
ParntershipInvestments
Dec. 31, 2024
USD ($)
Schedule Of Available For Sale Securities [Line Items]    
Investments in a single issuer as a percentage of shareholders' equity 2.00% 1.70%
Number of limited partnership investments | ParntershipInvestments 3  
Fixed maturity securities with market value $ 0 $ 0
Investments in insurance enhanced bonds $ 1,300,000  
Insurance enhanced bonds as a percentage of total cash and invested assets 0.10%  
Investments in collateralized mortgage obligations, commercial mortgage-backed securities and taxable municipal bonds $ 1,300,000  
Equity securities, at fair value 12,569,000 12,284,000
Future Funding Commitments 14,214,000 14,214,000
Limited partnership investments with carrying value of fair value $ 22,100,000 29,400,000
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 $ 2,400,000 2,600,000
Future Funding Commitments 14,200,000 14,200,000
Variable interest entities, maximum exposure to loss 16,600,000 16,800,000
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 7,200,000 8,900,000
Variable interest entities, maximum exposure to loss 7,200,000 8,900,000
Assured Guaranty Corporation    
Schedule Of Available For Sale Securities [Line Items]    
Investments in collateralized mortgage obligations, commercial mortgage-backed securities and taxable municipal bonds 400,000  
Ambac Financial Group    
Schedule Of Available For Sale Securities [Line Items]    
Investments in collateralized mortgage obligations, commercial mortgage-backed securities and taxable municipal bonds 900,000  
Other Assets    
Schedule Of Available For Sale Securities [Line Items]    
Accrued interest receivable related to fixed maturities 5,600,000 3,500,000
Preferred Stock    
Schedule Of Available For Sale Securities [Line Items]    
Equity securities, at fair value 12,600,000 $ 12,300,000
U.S. Treasuries    
Schedule Of Available For Sale Securities [Line Items]    
Gross unrealized losses 265,000  
Obligations of States and Political Subdivisions    
Schedule Of Available For Sale Securities [Line Items]    
Gross unrealized losses 489,000  
Mortgage Backed Securities    
Schedule Of Available For Sale Securities [Line Items]    
Gross unrealized losses 2,500,000  
Asset-backed Securities    
Schedule Of Available For Sale Securities [Line Items]    
Gross unrealized losses $ 2,166,000  
Weighted average credit enhancement 37.90%  
Commercial Mortgage-Backed Securities    
Schedule Of Available For Sale Securities [Line Items]    
Gross unrealized losses $ 1,573,000  
Weighted average credit enhancement 43.10%  
Corporate Bonds    
Schedule Of Available For Sale Securities [Line Items]    
Gross unrealized losses $ 1,547,000  
Foreign Corporate Bonds    
Schedule Of Available For Sale Securities [Line Items]    
Gross unrealized losses $ 1,039,000.000