v3.26.1
Investments - Additional Information (Detail)
$ in Thousands
 3 Months Ended
Mar. 31, 2026
USD ($)
Security
Mar. 31, 2025
USD ($)
Dec. 31, 2025
USD ($)
Marketable Securities [Line Items]      
Individual fixed maturity held in unrealized loss position | Security 179    
Number of fixed maturity securities, allowance for credit loss | Security 261    
Fixed maturity securities, held-to-maturity, allowance for credit losses $ 65   $ 73
Fixed maturity securities, available-for-sale, allowance for credit losses 0   0
Net realized gains (losses) on investments (3) $ 2  
Net unrealized gains (losses) on equity securities (1,653) $ (3,152)  
Corporate Bonds [Member]      
Marketable Securities [Line Items]      
Fixed maturity securities, held-to-maturity, allowance for credit losses $ 43   50
Number of majority securities | Security 8    
States and Political Subdivisions [Member]      
Marketable Securities [Line Items]      
Fixed maturity securities, held-to-maturity, allowance for credit losses $ 22   $ 23
Number of majority securities | Security 252    
Corporate Fixed Income Securities [Member] | Maximum [Member]      
Marketable Securities [Line Items]      
Investments maturity period using default rate 20 years