v3.26.1
Securities - Gross Unrealized Losses and Fair Value, Aggregated by Investment Category (Detail) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Schedule of Available-for-sale Securities [Line Items]    
12 Months or less, Fair Value $ 134,686 $ 72,020
12 Months or less, Unrealized Loss (998) (537)
More than 12 months, Fair Value 367,347 401,362
More than 12 months, Unrealized Loss (49,463) (46,602)
Total Fair Value 502,033 473,382
Total Unrealized Loss (50,461) (47,139)
U.S. Treasury Securities and Obligations of U.S. Government Agencies [Member]    
Schedule of Available-for-sale Securities [Line Items]    
12 Months or less, Fair Value 6,612 1,168
12 Months or less, Unrealized Loss (44) (2)
More than 12 months, Fair Value 43,285 47,644
More than 12 months, Unrealized Loss (1,148) (1,178)
Total Fair Value 49,897 48,812
Total Unrealized Loss (1,192) (1,180)
Obligations of States and Political Subdivisions [Member]    
Schedule of Available-for-sale Securities [Line Items]    
12 Months or less, Fair Value 87,192 12,606
12 Months or less, Unrealized Loss (670) (45)
More than 12 months, Fair Value 150,926 181,703
More than 12 months, Unrealized Loss (23,735) (21,690)
Total Fair Value 238,118 194,309
Total Unrealized Loss (24,405) (21,735)
Mortgage-backed Securities in Government Sponsored Entities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
12 Months or less, Fair Value 40,882 58,246
12 Months or less, Unrealized Loss (284) (490)
More than 12 months, Fair Value 173,136 172,015
More than 12 months, Unrealized Loss (24,580) (23,734)
Total Fair Value 214,018 230,261
Total Unrealized Loss $ (24,864) $ (24,224)