v3.26.1
Summary of Securities with Gross Unrealized Losses (Detail) - Fixed Income Securities - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Schedule Of Available For Sale Securities [Line Items]    
Less than 12 months, Fair Value $ 502,074 $ 79,220
Less than 12 months, Gross Unrealized Losses (1,561) (2,728)
12 months or longer, Fair Value 142,681 182,408
12 months or longer, Gross Unrealized Losses (9,801) (7,737)
Total, Fair Value 644,755 261,628
Total, Gross Unrealized Losses (11,362) (10,465)
U.S. Treasuries    
Schedule Of Available For Sale Securities [Line Items]    
Less than 12 months, Fair Value 315,544 21,804
Less than 12 months, Gross Unrealized Losses (155) (1)
12 months or longer, Fair Value 4,363 7,643
12 months or longer, Gross Unrealized Losses (96) (119)
Total, Fair Value 319,907 29,447
Total, Gross Unrealized Losses (251) (120)
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 9,259 12,714
12 months or longer, Gross Unrealized Losses (347) (350)
Total, Fair Value 9,259 12,714
Total, Gross Unrealized Losses (347) (350)
Mortgage Backed Securities    
Schedule Of Available For Sale Securities [Line Items]    
Less than 12 months, Fair Value 69,341 15,293
Less than 12 months, Gross Unrealized Losses (688) (716)
12 months or longer, Fair Value 22,559 24,918
12 months or longer, Gross Unrealized Losses (3,205) (2,735)
Total, Fair Value 91,900 40,211
Total, Gross Unrealized Losses (3,893) (3,451)
Asset-backed Securities    
Schedule Of Available For Sale Securities [Line Items]    
Less than 12 months, Fair Value 68,837 24,080
Less than 12 months, Gross Unrealized Losses (499) (1,872)
12 months or longer, Fair Value 33,575 31,604
12 months or longer, Gross Unrealized Losses (3,647) (1,777)
Total, Fair Value 102,412 55,684
Total, Gross Unrealized Losses (4,146) (3,649)
Commercial Mortgage-Backed Securities    
Schedule Of Available For Sale Securities [Line Items]    
Less than 12 months, Fair Value 32,349 13,954
Less than 12 months, Gross Unrealized Losses (185) (96)
12 months or longer, Fair Value 27,993 32,183
12 months or longer, Gross Unrealized Losses (1,220) (1,367)
Total, Fair Value 60,342 46,137
Total, Gross Unrealized Losses (1,405) (1,463)
Corporate Bonds    
Schedule Of Available For Sale Securities [Line Items]    
Less than 12 months, Fair Value 12,540 2,509
Less than 12 months, Gross Unrealized Losses (3) (26)
12 months or longer, Fair Value 28,995 48,935
12 months or longer, Gross Unrealized Losses (749) (841)
Total, Fair Value 41,535 51,444
Total, Gross Unrealized Losses (752) (867)
Foreign Corporate Bonds    
Schedule Of Available For Sale Securities [Line Items]    
Less than 12 months, Fair Value 3,463 1,580
Less than 12 months, Gross Unrealized Losses (31) (17)
12 months or longer, Fair Value 15,937 24,411
12 months or longer, Gross Unrealized Losses (537) (548)
Total, Fair Value 19,400 25,991
Total, Gross Unrealized Losses $ (568) $ (565)