Investment Securities - Summary of Amortized Cost, Gross Unrealized Gains and Losses, Allowance for Credit Losses and Fair Value of Investment Securities Available for Sale (Detail) - USD ($)	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Debt Securities Available For Sale Reconciliation Of Fair Value To Amortized Cost [Line Items]
Amortized Cost	$ 153,102,000	$ 120,372,000
Gross Unrealized Gains	167,000	1,280,000
Gross Unrealized Losses	(7,679,000)	(6,162,000)
Allowance for Credit Losses	0	0
Fair Value	145,590,000	115,490,000
Held-to-Maturity, Amortized Cost	31,967,000	36,735,000
Gross Unrecognized Gain	6,000	0
Gross Unrecognized Losses	(1,689,000)	(2,499,000)
Held-to-maturity, Fair value	30,284,000	34,236,000
Allowance for Credit Losses	(459,000)	(512,000)
US Government Agency securities [Member]
Debt Securities Available For Sale Reconciliation Of Fair Value To Amortized Cost [Line Items]
Amortized Cost	13,017,000	12,711,000
Gross Unrealized Gains	96,000	279,000
Gross Unrealized Losses	(40,000)	(5,000)
Allowance for Credit Losses	0	0
Fair Value	13,073,000	12,985,000
US Government Treasury securities [Member]
Debt Securities Available For Sale Reconciliation Of Fair Value To Amortized Cost [Line Items]
Amortized Cost		4,925,000
Gross Unrealized Gains		17,000
Gross Unrealized Losses		0
Allowance for Credit Losses		0
Fair Value		4,942,000
Obligations of state and political subdivisions [Member]
Debt Securities Available For Sale Reconciliation Of Fair Value To Amortized Cost [Line Items]
Amortized Cost	51,254,000	49,640,000
Gross Unrealized Gains	10,000	420,000
Gross Unrealized Losses	(4,063,000)	(3,015,000)
Allowance for Credit Losses	0	0
Fair Value	47,201,000	47,045,000
Mortgage-backed securities in government-sponsored entities [Member]
Debt Securities Available For Sale Reconciliation Of Fair Value To Amortized Cost [Line Items]
Amortized Cost	88,289,000	50,795,000
Gross Unrealized Gains	61,000	515,000
Gross Unrealized Losses	(3,567,000)	(3,129,000)
Allowance for Credit Losses	0	0
Fair Value	84,783,000	48,181,000
Other securities [Member]
Debt Securities Available For Sale Reconciliation Of Fair Value To Amortized Cost [Line Items]
Amortized Cost	542,000	2,301,000
Gross Unrealized Gains	0	49,000
Gross Unrealized Losses	(9,000)	(13,000)
Allowance for Credit Losses	0	0
Fair Value	533,000	2,337,000
Corporate Debentures [Member]
Debt Securities Available For Sale Reconciliation Of Fair Value To Amortized Cost [Line Items]
Held-to-Maturity, Amortized Cost	15,250,000	15,000,000
Gross Unrecognized Gain	0	0
Gross Unrecognized Losses	(984,000)	(1,592,000)
Held-to-maturity, Fair value	14,266,000	13,408,000
Allowance for Credit Losses	(459,000)	(512,000)	$ 0
Structured Mortgage-backed Securities [Member]
Debt Securities Available For Sale Reconciliation Of Fair Value To Amortized Cost [Line Items]
Held-to-Maturity, Amortized Cost	16,717,000	21,735,000
Gross Unrecognized Gain	6,000	0
Gross Unrecognized Losses	(705,000)	(907,000)
Held-to-maturity, Fair value	16,018,000	20,828,000
Allowance for Credit Losses	$ 0	$ 0