Investment Securities - Summary of Securities with Gross Unrealized Losses (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Losses, Less than Twelve Months	$ (40)	$ (282)
Fair Value, Less than Twelve Months	1,916	10,636
Gross Unrealized Losses, Twelve Months and Over	(6,474)	(6,030)
Fair Value, Twelve Months and Over	50,990	43,509
Mortgage-backed Securities, Principally Obligations of US Federal Agencies [Member]
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Losses, Less than Twelve Months	(39)	(78)
Fair Value, Less than Twelve Months	1,875	5,797
Gross Unrealized Losses, Twelve Months and Over	(5,035)	(4,714)
Fair Value, Twelve Months and Over	36,766	33,971
State and Municipalities [Member]
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Losses, Less than Twelve Months	(1)	(204)
Fair Value, Less than Twelve Months	41	4,839
Gross Unrealized Losses, Twelve Months and Over	(1,414)	(1,296)
Fair Value, Twelve Months and Over	12,064	7,371
Agency Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Losses, Less than Twelve Months	0	0
Fair Value, Less than Twelve Months	0	0
Gross Unrealized Losses, Twelve Months and Over	(25)	(20)
Fair Value, Twelve Months and Over	$ 2,160	$ 2,167