Investment Securities - Summary of Amortized Cost, Gross Unrealized Gains and Losses, and Fair Value of Investment Securities Available for Sale (Detail) - USD ($)	Jun. 30, 2025	Mar. 31, 2025	Dec. 31, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023
Debt Securities Available For Sale Reconciliation Of Fair Value To Amortized Cost [Line Items]
Amortized Cost	$ 175,857,000		$ 153,102,000
Gross Unrealized Gains	746,000		167,000
Gross Unrealized Losses	(7,034,000)		(7,679,000)
Allowance for Credit Losses	0		0
Fair Value	169,569,000		145,590,000
Held-to-Maturity, Amortized Cost	27,284,000		31,967,000
Gross Unrecognized Gain	6,000		6,000
Gross Unrecognized Losses	(1,186,000)		(1,689,000)
Held-to-maturity, Fair value	26,104,000		30,284,000
Allowance for Credit Losses	(475,000)		(459,000)
US Government Agency securities [Member]
Debt Securities Available For Sale Reconciliation Of Fair Value To Amortized Cost [Line Items]
Amortized Cost	13,177,000		13,017,000
Gross Unrealized Gains	186,000		96,000
Gross Unrealized Losses	(18,000)		(40,000)
Allowance for Credit Losses	0		0
Fair Value	13,345,000		13,073,000
Obligations of state and political subdivisions [Member]
Debt Securities Available For Sale Reconciliation Of Fair Value To Amortized Cost [Line Items]
Amortized Cost	50,758,000		51,254,000
Gross Unrealized Gains	16,000		10,000
Gross Unrealized Losses	(4,455,000)		(4,063,000)
Allowance for Credit Losses	0		0
Fair Value	46,319,000		47,201,000
Mortgage-backed securities in government-sponsored entities [Member]
Debt Securities Available For Sale Reconciliation Of Fair Value To Amortized Cost [Line Items]
Amortized Cost	111,564,000		88,289,000
Gross Unrealized Gains	544,000		61,000
Gross Unrealized Losses	(2,554,000)		(3,567,000)
Allowance for Credit Losses	0		0
Fair Value	109,554,000		84,783,000
Other securities [Member]
Debt Securities Available For Sale Reconciliation Of Fair Value To Amortized Cost [Line Items]
Amortized Cost	358,000		542,000
Gross Unrealized Gains	0		0
Gross Unrealized Losses	(7,000)		(9,000)
Allowance for Credit Losses	0		0
Fair Value	351,000		533,000
Corporate Debentures [Member]
Debt Securities Available For Sale Reconciliation Of Fair Value To Amortized Cost [Line Items]
Held-to-Maturity, Amortized Cost	12,250,000		15,250,000
Gross Unrecognized Gain	0		0
Gross Unrecognized Losses	(728,000)		(984,000)
Held-to-maturity, Fair value	11,522,000		14,266,000
Allowance for Credit Losses	(475,000)	$ (421,000)	(459,000)	$ (502,000)	$ (507,000)	$ (512,000)
Structured Mortgage-backed Securities [Member]
Debt Securities Available For Sale Reconciliation Of Fair Value To Amortized Cost [Line Items]
Held-to-Maturity, Amortized Cost	15,034,000		16,717,000
Gross Unrecognized Gain	6,000		6,000
Gross Unrecognized Losses	(458,000)		(705,000)
Held-to-maturity, Fair value	14,582,000		16,018,000
Allowance for Credit Losses	$ 0		$ 0