Commitments and Contingencies - Additional Information (Detail) - USD ($)	Sep. 30, 2023	Dec. 31, 2022
Accounting Standards Update 2016-13 [Member]
Loss Contingencies [Line Items]
Outstanding loan commitments expected to fund	$ 41,100,000
Establishment of allowance for credit losses unfunded loan commitment	665,000
Commitments to Extend Credit [Member]
Loss Contingencies [Line Items]
Outstanding commitments	98,242,000	$ 84,022,000
Commitments to Extend Credit [Member] | Accounting Standards Update 2016-13 [Member]
Loss Contingencies [Line Items]
Outstanding commitments	55,200,000
Establishment of allowance for credit losses unfunded loan commitment	909,000
Mortgage Partnership Finance Program [Member]
Loss Contingencies [Line Items]
Commitments	1,000,000
Other commitments	$ 0	$ 0