v3.25.1
Investments - Summary of Securities with Gross Unrealized Loss Positions Aggregated by Investment Category (Detail) - USD ($)
$ in Thousands
Mar. 31, 2025
Dec. 31, 2024
Schedule of Available-for-sale Securities [Line Items]    
Gross Unrealized Loss, Less than Twelve Months $ (50) $ (2,116)
Estimated Fair Value, Less than Twelve Months 6,776 104,067
Gross Unrealized Loss, Twelve Months or Longer (528) (981)
Estimated Fair Value, Twelve Months or Longer 91,643 120,127
Gross Unrealized Loss, Total (578) (3,097)
Estimated Fair Value, Total 98,419 224,194
U.S. Treasury and U.S. Government Agencies [Member] | Fixed-Maturity Securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Gross Unrealized Loss, Less than Twelve Months (1) (2,063)
Estimated Fair Value, Less than Twelve Months 498 97,771
Gross Unrealized Loss, Twelve Months or Longer (305) (663)
Estimated Fair Value, Twelve Months or Longer 83,792 104,872
Gross Unrealized Loss, Total (306) (2,726)
Estimated Fair Value, Total 84,290 202,643
Corporate Bonds [Member] | Fixed-Maturity Securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Gross Unrealized Loss, Less than Twelve Months (19) (53)
Estimated Fair Value, Less than Twelve Months 5,814 6,296
Gross Unrealized Loss, Twelve Months or Longer (223) (318)
Estimated Fair Value, Twelve Months or Longer 7,851 15,255
Gross Unrealized Loss, Total (242) (371)
Estimated Fair Value, Total 13,665 $ 21,551
Exchange-Traded Debt [Member] | Fixed-Maturity Securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Gross Unrealized Loss, Less than Twelve Months (30)  
Estimated Fair Value, Less than Twelve Months 464  
Gross Unrealized Loss, Total (30)  
Estimated Fair Value, Total $ 464