Basis of Presentation - Schedule of Total Allowance for Credit Losses (Detail) - USD ($)	Mar. 31, 2023	Jan. 01, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Securities held to maturity	$ 63,000
Total allowance for credit losses	4,596,000		$ 2,290,000	$ 4,156,000	$ 4,026,000
Pre Adoption [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment			2,290,000
Total allowance for credit losses			2,431,000
Pre Adoption [Member] | Commercial [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment			435,000
Pre Adoption [Member] | Real Estate - Commercial [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment			760,000
Pre Adoption [Member] | Other Real Estate Construction [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment			177,000
Pre Adoption [Member] | Real Estate - Residential [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment			561,000
Pre Adoption [Member] | Home Equity [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment			277,000
Pre Adoption [Member] | Consumer Loans [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment			76,000
Pre Adoption [Member] | Other Loans [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment			4,000
Unfunded Loan Commitment [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment	143,000		141,000
Unfunded Loan Commitment [Member] | Pre Adoption [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Total allowance for credit losses			$ 141,000
ASU 2016-13 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Securities held to maturity		$ 70,000
Loans held for investment		4,697,000
Total allowance for credit losses		4,847,000
ASU 2016-13 [Member] | State and Political Subdivisions [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Securities held to maturity		3,000
ASU 2016-13 [Member] | Corporate Bonds [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Securities held to maturity		67,000
ASU 2016-13 [Member] | Commercial [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment		1,137,000
ASU 2016-13 [Member] | Real Estate - Commercial [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment		1,777,000
ASU 2016-13 [Member] | Other Real Estate Construction [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment		306,000
ASU 2016-13 [Member] | Real Estate 1-4 Family Construction [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment		14,000
ASU 2016-13 [Member] | Real Estate - Residential [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment		635,000
ASU 2016-13 [Member] | Home Equity [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment		652,000
ASU 2016-13 [Member] | Consumer Loans [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment		167,000
ASU 2016-13 [Member] | Other Loans [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment		9,000
ASU 2016-13 [Member] | Impact of Adoption [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Securities held to maturity	70,000
Loans held for investment	2,407,000
Total allowance for credit losses	2,416,000
ASU 2016-13 [Member] | Impact of Adoption [Member] | State and Political Subdivisions [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Securities held to maturity	3,000
ASU 2016-13 [Member] | Impact of Adoption [Member] | Corporate Bonds [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Securities held to maturity	67,000
ASU 2016-13 [Member] | Impact of Adoption [Member] | Commercial [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment	702,000
ASU 2016-13 [Member] | Impact of Adoption [Member] | Real Estate - Commercial [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment	1,017,000
ASU 2016-13 [Member] | Impact of Adoption [Member] | Other Real Estate Construction [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment	129,000
ASU 2016-13 [Member] | Impact of Adoption [Member] | Real Estate 1-4 Family Construction [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment	14,000
ASU 2016-13 [Member] | Impact of Adoption [Member] | Real Estate - Residential [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment	74,000
ASU 2016-13 [Member] | Impact of Adoption [Member] | Home Equity [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment	375,000
ASU 2016-13 [Member] | Impact of Adoption [Member] | Consumer Loans [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment	91,000
ASU 2016-13 [Member] | Impact of Adoption [Member] | Other Loans [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loans held for investment	5,000
ASU 2016-13 [Member] | Unfunded Loan Commitment [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Total allowance for credit losses		$ 150,000
ASU 2016-13 [Member] | Unfunded Loan Commitment [Member] | Impact of Adoption [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Total allowance for credit losses	$ 9,000