Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Line Items]
Carryforward of charitable contributions	$ 443,000	$ 626,000
Valuation allowance	$ 60,000	85,000
Charitable contributions limit percentage of taxable income deduction	10.00%
Excess charitable contributions carryforwards succeeding period	5 years
Charitable contribution carryforward utilization period	6 years
Deferred tax assets, tax reserves for loan losses	$ 2,300,000
Percentage of tax reserve for loan losses used for purpose other than to absorb loan losses subject to taxation	150.00%
Reserve for loan losses of deferred tax liability not provided	$ 623,000
Amount of interest and penalties recorded	0	$ 0
NEW HAMPSHIRE | State [Member] | Business Enterprise Tax Credit Carry Forward [Member]
Income Tax Disclosure [Line Items]
Tax credit carry forward	$ 66,000