Derivatives and Hedging Activities - Additional Information (Detail)		3 Months Ended		9 Months Ended
	Jan. 17, 2023 USD ($)	Sep. 30, 2024 USD ($) Derivative	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) Derivative	Sep. 30, 2023 USD ($)	Jul. 12, 2024 USD ($)	Dec. 31, 2023 USD ($)
Derivatives Fair Value [Line Items]
Interest rate swaps				$ (152,000)	$ (961,000)
Cash in collateral returned		$ 16,517,000		16,517,000			$ 6,069,000
Cumulative amount of fair value hedging adjustment included in the carrying amount of the hedged assets/(liabilities)		966,000		966,000			758,000
Carrying amount of savings deposit		60,966,000		60,966,000			60,758,000
Loans [Member]
Derivatives Fair Value [Line Items]
Cumulative amount of fair value hedging adjustment included in the carrying amount of the hedged assets/(liabilities)		788,000		788,000			632,000
Carrying amount of savings deposit		50,788,000		50,788,000			50,632,000
Securities Available-for-sale, at Fair Value [Member]
Derivatives Fair Value [Line Items]
Cumulative amount of fair value hedging adjustment included in the carrying amount of the hedged assets/(liabilities)		178,000		178,000			126,000
Carrying amount of savings deposit		10,178,000		10,178,000			10,126,000
Interest Rate Swap 2021 [Member]
Derivatives Fair Value [Line Items]
Gain on derivative	$ 849,000
Cash in collateral returned	$ 536,000
Interest Rate Swap Contracts and Customer Loan Swaps [Member]
Derivatives Fair Value [Line Items]
Cash collateral from counterparties		2,300,000		2,300,000			1,600,000
Designated as Hedging Instrument [Member]
Derivatives Fair Value [Line Items]
Notional amount		0		0		$ 10,000,000
Carrying amount of savings deposit						$ 21,200,000
Derivative assets, notional amount		70,000,000		70,000,000
Designated as Hedging Instrument [Member] | Loans [Member]
Derivatives Fair Value [Line Items]
Designated hedged items		50,000,000		50,000,000
Derivative assets, notional amount		50,000,000		50,000,000
Designated as Hedging Instrument [Member] | Securities Available-for-sale, at Fair Value [Member]
Derivatives Fair Value [Line Items]
Designated hedged items		10,000,000		10,000,000			$ 10,000,000
Derivative assets, notional amount		10,000,000		10,000,000
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivatives Fair Value [Line Items]
Interest rate swaps		0	$ 0	(112,000)	$ (112,000)
Designated as Hedging Instrument [Member] | Fixed Interest Rate Swap [Member]
Derivatives Fair Value [Line Items]
Interest rate swaps		(152,000)		(152,000)
Interest rate swaps interest income reclassified from AOCI into expense		$ 21,000		$ 21,000
Cash Flow Hedges on 90-day Advances from FHLB [Member]
Derivatives Fair Value [Line Items]
Average fixed interest rate						4.33%
Fixed annual rate						5.32%
Cash Flow Hedges on 90-day Advances from FHLB [Member] | Interest Rate Swap [Member]
Derivatives Fair Value [Line Items]
Number of notional interest rate swaps | Derivative		2		2
Cash Flow Hedges on 90-day Advances from FHLB [Member] | Designated as Hedging Instrument [Member] | Interest Rate Swap 2021 [Member]
Derivatives Fair Value [Line Items]
Notional amount		$ 5,000,000		$ 5,000,000
Fair Value Hedging [Member]
Derivatives Fair Value [Line Items]
Remaining maturity		1 year 11 months 19 days		1 year 11 months 19 days			2 years 8 months 23 days
Average fixed interest rate		4.29%		4.29%
Fixed annual rate		5.30%		5.30%
Fair Value Hedging [Member] | Fixed Rate Assets [Member] | Loans [Member]
Derivatives Fair Value [Line Items]
Cumulative amount of fair value hedging adjustment included in the carrying amount of the hedged assets/(liabilities)		$ 788,000		$ 788,000			$ 632,000
Fair Value Hedging [Member] | Fixed Rate Assets [Member] | Securities Available-for-sale, at Fair Value [Member]
Derivatives Fair Value [Line Items]
Amortized cost basis of the closed portfolios used in hedging relationships		19,300,000		19,300,000			19,300,000
Cumulative amount of fair value hedging adjustment included in the carrying amount of the hedged assets/(liabilities)		$ 178,000		$ 178,000			$ 126,000