Note 3 - Loans - Summary of Past Due Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Total loans	$ 483,634	$ 483,913
Nonaccrual Loans	0
Loans by credit quality	483,634	483,913
Financial Asset, 30 to 59 Days Past Due [Member]
Total loans	444
Loans by credit quality	444
Financial Asset, 60 to 89 Days Past Due [Member]
Total loans	82
Loans by credit quality	82
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Total loans	0
Loans by credit quality	0
Financial Asset, Past Due [Member]
Total loans	526
Loans by credit quality	526
Financial Asset, Not Past Due [Member]
Total loans	483,108
Loans by credit quality	483,108
Mortgage Receivable [Member]
Total loans	382,387	336,059
Loans by credit quality	382,387	336,059
Mortgage Receivable [Member] | Commercial Real Estate Portfolio Segment [Member]
Total loans	140,961	133,473
Nonaccrual Loans	0	0
Loans by credit quality	140,961	133,473
Mortgage Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Total loans	0	0
Loans by credit quality	0	0
Mortgage Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Total loans	0
Loans by credit quality	0
Mortgage Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Total loans	0
Loans by credit quality	0
Mortgage Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Financial Asset, Past Due [Member]
Total loans	0	0
Loans by credit quality	0	0
Mortgage Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Financial Asset, Not Past Due [Member]
Total loans	140,961	133,473
Loans by credit quality	140,961	133,473
Mortgage Receivable [Member] | Residential Portfolio Segment [Member]
Total loans	181,031	158,120
Nonaccrual Loans	0	666
Loans by credit quality	181,031	158,120
Mortgage Receivable [Member] | Residential Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Total loans	0	536
Loans by credit quality	0	536
Mortgage Receivable [Member] | Residential Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Total loans	0	0
Loans by credit quality	0	0
Mortgage Receivable [Member] | Residential Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Total loans	0	0
Loans by credit quality	0	0
Mortgage Receivable [Member] | Residential Portfolio Segment [Member] | Financial Asset, Past Due [Member]
Total loans	0	536
Loans by credit quality	0	536
Mortgage Receivable [Member] | Residential Portfolio Segment [Member] | Financial Asset, Not Past Due [Member]
Total loans	181,031	156,918
Loans by credit quality	181,031	156,918
Mortgage Receivable [Member] | Real Estate Construction Loan [Member]
Total loans	60,395	44,466
Nonaccrual Loans	0	0
Loans by credit quality	60,395	44,466
Mortgage Receivable [Member] | Real Estate Construction Loan [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Total loans	0	195
Loans by credit quality	0	195
Mortgage Receivable [Member] | Real Estate Construction Loan [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Total loans	82	0
Loans by credit quality	82	0
Mortgage Receivable [Member] | Real Estate Construction Loan [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Total loans	0	0
Loans by credit quality	0	0
Mortgage Receivable [Member] | Real Estate Construction Loan [Member] | Financial Asset, Past Due [Member]
Total loans	82	195
Loans by credit quality	82	195
Mortgage Receivable [Member] | Real Estate Construction Loan [Member] | Financial Asset, Not Past Due [Member]
Total loans	60,313	44,271
Loans by credit quality	60,313	44,271
Loans and Finance Receivables [Member]
Total loans		483,913
Nonaccrual Loans		1,251
Loans by credit quality		483,913
Loans and Finance Receivables [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Total loans		731
Loans by credit quality		731
Loans and Finance Receivables [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Total loans		0
Loans by credit quality		0
Loans and Finance Receivables [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Total loans		0
Loans by credit quality		0
Loans and Finance Receivables [Member] | Financial Asset, Past Due [Member]
Total loans		731
Loans by credit quality		731
Loans and Finance Receivables [Member] | Financial Asset, Not Past Due [Member]
Total loans		481,931
Loans by credit quality		481,931
Loans and Finance Receivables [Member] | Commercial Portfolio Segment [Member]
Total loans	93,900	141,542
Nonaccrual Loans	0	585
Loans by credit quality	93,900	141,542
Loans and Finance Receivables [Member] | Commercial Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Total loans	444	0
Loans by credit quality	444	0
Loans and Finance Receivables [Member] | Commercial Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Total loans	0	0
Loans by credit quality	0	0
Loans and Finance Receivables [Member] | Commercial Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Total loans	0	0
Loans by credit quality	0	0
Loans and Finance Receivables [Member] | Commercial Portfolio Segment [Member] | Financial Asset, Past Due [Member]
Total loans	444	0
Loans by credit quality	444	0
Loans and Finance Receivables [Member] | Commercial Portfolio Segment [Member] | Financial Asset, Not Past Due [Member]
Total loans	93,456	140,957
Loans by credit quality	93,456	140,957
Loans and Finance Receivables [Member] | Consumer Portfolio Segment [Member]
Total loans	7,347	6,312
Nonaccrual Loans	0	0
Loans by credit quality	7,347	6,312
Loans and Finance Receivables [Member] | Consumer Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Total loans	0	0
Loans by credit quality	0	0
Loans and Finance Receivables [Member] | Consumer Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Total loans	0	0
Loans by credit quality	0	0
Loans and Finance Receivables [Member] | Consumer Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Total loans	0	0
Loans by credit quality	0	0
Loans and Finance Receivables [Member] | Consumer Portfolio Segment [Member] | Financial Asset, Past Due [Member]
Total loans	0	0
Loans by credit quality	0	0
Loans and Finance Receivables [Member] | Consumer Portfolio Segment [Member] | Financial Asset, Not Past Due [Member]
Total loans	7,347	6,312
Loans by credit quality	$ 7,347	$ 6,312