Summary of Significant Accounting Policies - Summary of Category of Loans and Impact of Change from Adoption (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Jun. 30, 2023	Jan. 01, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans	$ 680,980			$ 626,958
Allowance for credit/loan losses	(6,691)	$ (6,559)		(6,838)	$ (7,008)	$ (7,268)	$ (7,618)
Net Total Loans	674,258			620,333
ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans			$ 626,958
Deferred loan (fees) costs, net			213
Allowance for credit/loan losses			(6,279)
Net Total Loans			620,892
Pre-adoption [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans				626,958
Deferred loan (fees) costs, net				213
Allowance for credit/loan losses			(6,838)	(6,838)
Net Total Loans				620,333
Cumulative Effect of Adoption [Memnber] | Adoption Impact [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit/loan losses			559	559
Net Total Loans				559
Commercial and Industrial [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans	143,227			129,343
Allowance for credit/loan losses	(1,963)	(2,119)		(1,110)	(1,249)	(1,213)	(1,240)
Commercial and Industrial [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans			127,134
Allowance for credit/loan losses			(1,768)
Commercial and Industrial [Member] | Pre-adoption [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans				129,343
Allowance for credit/loan losses			(1,110)
Commercial and Industrial [Member] | Cumulative Effect of Adoption [Memnber] | Adoption Impact [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans				(2,209)
Allowance for credit/loan losses			(658)
Commercial Real Estate [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans	188,910			231,785
Allowance for credit/loan losses	(2,129)	(1,882)		(2,760)	$ (2,112)	$ (2,422)	$ (2,838)
Commercial Real Estate [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans			161,160
Allowance for credit/loan losses			(2,219)
Commercial Real Estate [Member] | Pre-adoption [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans				231,785
Allowance for credit/loan losses			(2,760)
Commercial Real Estate [Member] | Cumulative Effect of Adoption [Memnber] | Adoption Impact [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans				(70,625)
Allowance for credit/loan losses			541
Commercial Lessors of Buildings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans	78,520
Allowance for credit/loan losses	(1,226)	(1,237)
Commercial Lessors of Buildings [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans			83,728
Allowance for credit/loan losses			(974)
Commercial Lessors of Buildings [Member] | Cumulative Effect of Adoption [Memnber] | Adoption Impact [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans				83,728
Allowance for credit/loan losses			(974)
Construction [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans	44,446
Allowance for credit/loan losses	(255)	(283)		(803)
Construction [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans			44,866
Allowance for credit/loan losses			(288)
Construction [Member] | Pre-adoption [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans				55,318
Allowance for credit/loan losses			(803)
Construction [Member] | Cumulative Effect of Adoption [Memnber] | Adoption Impact [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans				(10,452)
Allowance for credit/loan losses			515
Consumer Mortgage [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans	167,419
Allowance for credit/loan losses	(775)	(714)		(1,268)
Consumer Mortgage [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans			149,787
Allowance for credit/loan losses			(688)
Consumer Mortgage [Member] | Pre-adoption [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans				194,125
Allowance for credit/loan losses			(1,268)
Consumer Mortgage [Member] | Cumulative Effect of Adoption [Memnber] | Adoption Impact [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans				(44,338)
Allowance for credit/loan losses			580
Home Equity Line of Credit [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans	41,093
Allowance for credit/loan losses	(187)	(178)
Home Equity Line of Credit [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans			44,243
Allowance for credit/loan losses			(201)
Home Equity Line of Credit [Member] | Cumulative Effect of Adoption [Memnber] | Adoption Impact [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans				44,243
Allowance for credit/loan losses			(201)
Consumer Installment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans	11,197
Allowance for credit/loan losses	(57)	(52)		(233)
Consumer Installment [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans			9,657
Allowance for credit/loan losses			(50)
Consumer Installment [Member] | Pre-adoption [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans				16,387
Allowance for credit/loan losses			(233)
Consumer Installment [Member] | Cumulative Effect of Adoption [Memnber] | Adoption Impact [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans				(6,730)
Allowance for credit/loan losses			183
Consumer Indirect [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans	6,168
Allowance for credit/loan losses	$ (99)	$ (94)
Consumer Indirect [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans			6,383
Allowance for credit/loan losses			(91)
Consumer Indirect [Member] | Cumulative Effect of Adoption [Memnber] | Adoption Impact [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total Loans				$ 6,383
Allowance for credit/loan losses			$ (91)