v3.25.1
Summary of Securities with Gross Unrealized Losses (Detail) - Fixed Income Securities - USD ($)
$ in Thousands
Mar. 31, 2025
Dec. 31, 2024
Schedule Of Available For Sale Securities [Line Items]    
Less than 12 months, Fair Value $ 283,765 $ 80,491
Less than 12 months, Gross Unrealized Losses (404) (923)
12 months or longer, Fair Value 313,084 355,303
12 months or longer, Gross Unrealized Losses (10,913) (14,013)
Total, Fair Value 596,849 435,794
Total, Gross Unrealized Losses (11,317) (14,936)
U.S. Treasuries    
Schedule Of Available For Sale Securities [Line Items]    
Less than 12 months, Fair Value 212,512 12,909
Less than 12 months, Gross Unrealized Losses (57) (180)
12 months or longer, Fair Value 50,659 67,662
12 months or longer, Gross Unrealized Losses (365) (604)
Total, Fair Value 263,171 80,571
Total, Gross Unrealized Losses (422) (784)
Obligations of States and Political Subdivisions    
Schedule Of Available For Sale Securities [Line Items]    
Less than 12 months, Fair Value 0 0
Less than 12 months, Gross Unrealized Losses 0 0
12 months or longer, Fair Value 16,484 16,335
12 months or longer, Gross Unrealized Losses (615) (790)
Total, Fair Value 16,484 16,335
Total, Gross Unrealized Losses (615) (790)
Mortgage Backed Securities    
Schedule Of Available For Sale Securities [Line Items]    
Less than 12 months, Fair Value 38,437 20,832
Less than 12 months, Gross Unrealized Losses (228) (336)
12 months or longer, Fair Value 23,660 26,802
12 months or longer, Gross Unrealized Losses (2,358) (2,948)
Total, Fair Value 62,097 47,634
Total, Gross Unrealized Losses (2,586) (3,284)
Asset-backed Securities    
Schedule Of Available For Sale Securities [Line Items]    
Less than 12 months, Fair Value 11,417 7,239
Less than 12 months, Gross Unrealized Losses (18) (49)
12 months or longer, Fair Value 44,887 46,792
12 months or longer, Gross Unrealized Losses (2,328) (2,833)
Total, Fair Value 56,304 54,031
Total, Gross Unrealized Losses (2,346) (2,882)
Commercial Mortgage-Backed Securities    
Schedule Of Available For Sale Securities [Line Items]    
Less than 12 months, Fair Value 5,918 7,551
Less than 12 months, Gross Unrealized Losses (36) (242)
12 months or longer, Fair Value 50,333 55,750
12 months or longer, Gross Unrealized Losses (1,750) (2,246)
Total, Fair Value 56,251 63,301
Total, Gross Unrealized Losses (1,786) (2,488)
Corporate Bonds    
Schedule Of Available For Sale Securities [Line Items]    
Less than 12 months, Fair Value 14,696 14,325
Less than 12 months, Gross Unrealized Losses (23) (54)
12 months or longer, Fair Value 83,580 95,266
12 months or longer, Gross Unrealized Losses (2,128) (2,837)
Total, Fair Value 98,276 109,591
Total, Gross Unrealized Losses (2,151) (2,891)
Foreign Corporate Bonds    
Schedule Of Available For Sale Securities [Line Items]    
Less than 12 months, Fair Value 785 17,635
Less than 12 months, Gross Unrealized Losses (42) (62)
12 months or longer, Fair Value 43,481 46,696
12 months or longer, Gross Unrealized Losses (1,369) (1,755)
Total, Fair Value 44,266 64,331
Total, Gross Unrealized Losses $ (1,411) $ (1,817)