Securities - Gross Unrealized Losses, Aggregated by Investment Category and Length of Time (Detail) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Losses, Less Than Twelve Months	$ (425)	$ (1,359)
Fair Value, Less Than Twelve Months	73,807	91,400
Gross Unrealized Losses, Twelve Months and Over	(25,308)	(30,631)
Fair Value, Twelve Months and Over	313,390	313,454
Gross Unrealized Losses, Total	(25,733)	(31,990)
Fair Value, Total	387,197	404,854
U.S. Treasury [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Losses, Less Than Twelve Months	(179)	(467)
Fair Value, Less Than Twelve Months	35,601	31,533
Gross Unrealized Losses, Twelve Months and Over	(4,056)	(4,948)
Fair Value, Twelve Months and Over	62,680	62,151
Gross Unrealized Losses, Total	(4,235)	(5,415)
Fair Value, Total	98,281	93,684
U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Losses, Twelve Months and Over	(7,687)	(9,494)
Fair Value, Twelve Months and Over	131,113	131,335
Gross Unrealized Losses, Total	(7,687)	(9,494)
Fair Value, Total	131,113	131,335
Mortgage-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Losses, Less Than Twelve Months	(147)	(668)
Fair Value, Less Than Twelve Months	31,890	51,236
Gross Unrealized Losses, Twelve Months and Over	(10,095)	(11,986)
Fair Value, Twelve Months and Over	66,396	66,877
Gross Unrealized Losses, Total	(10,242)	(12,654)
Fair Value, Total	98,286	118,113
State and Local Governments [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Losses, Less Than Twelve Months	(99)	(224)
Fair Value, Less Than Twelve Months	6,316	8,631
Gross Unrealized Losses, Twelve Months and Over	(3,470)	(4,203)
Fair Value, Twelve Months and Over	53,201	53,091
Gross Unrealized Losses, Total	(3,569)	(4,427)
Fair Value, Total	$ 59,517	$ 61,722