Investment Securities - Summary of Securities with Gross Unrealized Losses (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Losses, Less than Twelve Months	$ (2,533)	$ (412)
Fair Value, Less than Twelve Months	31,205	18,454
Gross Unrealized Losses, Twelve Months and Over	(3,572)	(42)
Fair Value, Twelve Months and Over	15,144	1,956
Mortgage-backed Securities, Principally Obligations of US Federal Agencies [Member]
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Losses, Less than Twelve Months	(2,284)	(403)
Fair Value, Less than Twelve Months	25,669	16,330
Gross Unrealized Losses, Twelve Months and Over	(3,072)	0
Fair Value, Twelve Months and Over	12,423	0
State and Municipalities [Member]
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Losses, Less than Twelve Months	(249)	(9)
Fair Value, Less than Twelve Months	5,536	2,124
Gross Unrealized Losses, Twelve Months and Over	(500)	(42)
Fair Value, Twelve Months and Over	$ 2,721	$ 1,956