Summary of Significant Accounting Policies - Impact of Change from Incurred Loss Model to Current Expected Credit Loss Model (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Jan. 01, 2023	Dec. 31, 2022	Dec. 31, 2021
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans	$ 6,607		$ 6,838	$ 7,618
ACL for off-balance sheet commitments	736
ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans		$ 6,279
ACL for off-balance sheet commitments		493
Total allowance for credit losses		6,772
Pre-adoption [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans		6,838	6,838
Total allowance for credit losses		6,838
Cumulative Effect of Adoption [Memnber] | Adoption Impact [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans		(559)	(559)
ACL for off-balance sheet commitments		493
Total allowance for credit losses		(66)
Commercial and Industrial [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans	1,737		1,110
Commercial and Industrial [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans		1,768
Commercial and Industrial [Member] | Pre-adoption [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans		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 allowance for credit losses - loans		658
Commercial Real Estate [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans	1,637		2,760	2,838
Commercial Real Estate [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans		2,219
Commercial Real Estate [Member] | Pre-adoption [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans		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 allowance for credit losses - loans		(541)
Commercial Lessors of Buildings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans	1,200
Commercial Lessors of Buildings [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans		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 allowance for credit losses - loans		974
Construction [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans	333		803
Construction [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans		288
Construction [Member] | Pre-adoption [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans		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 allowance for credit losses - loans		(515)
Consumer Mortgage [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans	1,107		1,268
Consumer Mortgage [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans		688
Consumer Mortgage [Member] | Pre-adoption [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans		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 allowance for credit losses - loans		(580)
Home Equity Line of Credit [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans	288
Home Equity Line of Credit [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans		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 allowance for credit losses - loans		201
Consumer Installment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans	76		233
Consumer Installment [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans		50
Consumer Installment [Member] | Pre-adoption [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans		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 allowance for credit losses - loans		(183)
Consumer Indirect [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans	$ 229
Consumer Indirect [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans		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 allowance for credit losses - loans		91
Unallocated [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans			$ 664	$ 747
Unallocated [Member] | Pre-adoption [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans		664
Unallocated [Member] | Cumulative Effect of Adoption [Memnber] | Adoption Impact [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total allowance for credit losses - loans		$ (664)