Loans and Allowance for Loan Losses - Aging of Past Due Accruing Loans and Nonaccrual Loans by Portfolio Segment (Details) - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
Nonaccrual	$ 2,893,000	$ 2,537,000
Total Past Due and Nonaccrual	3,893,000	4,642,000
Loans guaranteed by US government agency
Financing Receivable, Past Due [Line Items]
Nonaccrual	0	0
30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Still Accruing	298,000	893,000
60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Still Accruing	3,000	925,000
90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Still Accruing	699,000	287,000
Real Estate | Residential property
Financing Receivable, Past Due [Line Items]
Nonaccrual	0	0
Total Past Due and Nonaccrual	888,000	697,000
Real Estate | Residential property | 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Still Accruing	189,000	0
Real Estate | Residential property | 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Still Accruing	0	697,000
Real Estate | Residential property | 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Still Accruing	699,000	0
Real Estate | SBA property
Financing Receivable, Past Due [Line Items]
Nonaccrual	923,000	442,000
Total Past Due and Nonaccrual	923,000	1,236,000
Real Estate | SBA property | 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Still Accruing	0	794,000
Real Estate | SBA property | 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Still Accruing	0	0
Real Estate | SBA property | 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Still Accruing	0	0
Commercial and Industrial | Commercial lines of credit
Financing Receivable, Past Due [Line Items]
Nonaccrual	1,525,000	1,888,000
Total Past Due and Nonaccrual	1,525,000	1,888,000
Commercial and Industrial | Commercial lines of credit | 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Still Accruing	0	0
Commercial and Industrial | Commercial lines of credit | 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Still Accruing	0	0
Commercial and Industrial | Commercial lines of credit | 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Still Accruing	0	0
Commercial and Industrial | SBA commercial term
Financing Receivable, Past Due [Line Items]
Nonaccrual	378,000	159,000
Total Past Due and Nonaccrual	378,000	635,000
Commercial and Industrial | SBA commercial term | 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Still Accruing	0	0
Commercial and Industrial | SBA commercial term | 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Still Accruing	0	189,000
Commercial and Industrial | SBA commercial term | 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Still Accruing	0	287,000
Other consumer loans
Financing Receivable, Past Due [Line Items]
Nonaccrual	67,000	48,000
Total Past Due and Nonaccrual	178,000	186,000
Other consumer loans | 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Still Accruing	108,000	99,000
Other consumer loans | 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Still Accruing	3,000	39,000
Other consumer loans | 90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Still Accruing	$ 0	$ 0