Income Taxes - Tax Effects of Temporary Differences of Deferred Tax Assets and Deferred Tax Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Components Of Deferred Tax Assets And Liabilities [Abstract]
Allowance for loan losses	$ 1,698	$ 1,835
Unrealized loss on securities	565
Other	50	22
Deferred tax assets	2,313	1,857
Premises and equipment	(683)	(564)
Federal Home Loan Bank stock dividends	(376)	(376)
Deferred loan fees	(267)	(282)
Prepaid expenses	(157)	(114)
Unrealized gain on securities		(262)
Other	(505)	(412)
Deferred tax liabilities	(1,988)	(2,010)
Net deferred tax asset (liability)		$ (153)
Net deferred tax asset (liability)	$ 325