v3.26.1
Summary of Amortized Cost and Estimated Fair Value Through Fixed Maturities (Detail) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Schedule Of Available For Sale Securities [Line Items]    
Due in one year or less, Amortized Cost $ 818,421  
Due in one year through five years, Amortized Cost 98,157  
Due in five years through ten years, Amortized Cost 2,930  
Due after ten years, Amortized Cost 8,960  
Fixed maturities, Amortized Cost 1,331,715 $ 1,330,310
Due in one year or less, Estimated Fair value 818,354  
Due in one year through five years, Estimated Fair value 97,281  
Due in five years through ten years, Estimated Fair value 2,818  
Due after ten years, Estimated Fair value 8,307  
Fixed Maturities, estimated fair value 1,323,562 1,325,502
Mortgage Backed Securities    
Schedule Of Available For Sale Securities [Line Items]    
Amortized Cost 198,081  
Fixed maturities, Amortized Cost 198,081 199,901
Estimated Fair value 195,683  
Fixed Maturities, estimated fair value 195,683 199,060
Asset-backed Securities    
Schedule Of Available For Sale Securities [Line Items]    
Amortized Cost 148,969  
Fixed maturities, Amortized Cost 148,969 139,690
Estimated Fair value 145,979  
Fixed Maturities, estimated fair value 145,979 137,268
Commercial Mortgage-Backed Securities    
Schedule Of Available For Sale Securities [Line Items]    
Amortized Cost 56,197  
Fixed maturities, Amortized Cost 56,197 58,202
Estimated Fair value 55,140  
Fixed Maturities, estimated fair value $ 55,140 $ 56,828