Loans - Summary of Loans by Credit Quality Indicator (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Financing Receivable, Recorded Investment [Line Items]
Total Loans	$ 546,444	$ 609,870
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	327,829	368,067
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	5,872	4,897
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	17,958	31,675
Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans		317
Not Rated [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	194,785	204,914
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	128,653	191,540
Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	123,092	177,620
Commercial [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	543	2,352
Commercial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	3,543	9,644
Commercial [Member] | Not Rated [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,475	1,924
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	190,553	187,221
Commercial Real Estate [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	170,065	161,091
Commercial Real Estate [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	5,119	2,545
Commercial Real Estate [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	13,957	21,812
Commercial Real Estate [Member] | Not Rated [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,412	1,773
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	168,563	177,155
Residential Real Estate [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	164	174
Residential Real Estate [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	119	114
Residential Real Estate [Member] | Not Rated [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	168,280	176,867
Construction & Land Development [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	42,319	36,038
Construction & Land Development [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	34,508	29,182
Construction & Land Development [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	210
Construction & Land Development [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	329
Construction & Land Development [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans		317
Construction & Land Development [Member] | Not Rated [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	7,272	6,539
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	16,356	17,916
Consumer [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	10	105
Consumer [Member] | Not Rated [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	$ 16,346	$ 17,811