Note 4 - Loans and Allowance for Loan Losses - Recorded Investment in Nonperforming Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Total Nonperforming Loans	$ 6,258	$ 6,911
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Total Nonperforming Loans	4,406	4,732
Real Estate Mortgage Portfolio Segment [Member] | Land Loan [Member]
Total Nonperforming Loans	366	438
Real Estate Mortgage Portfolio Segment [Member] | Construction Loans [Member]
Total Nonperforming Loans
Real Estate Mortgage Portfolio Segment [Member] | Commercial Real Estate Loan [Member]
Total Nonperforming Loans	146	450
Commercial Portfolio Segment [Member]
Total Nonperforming Loans	119	522
Consumer Portfolio Segment [Member] | Home Equity and Second Mortgage [Member]
Total Nonperforming Loans	651	226
Consumer Portfolio Segment [Member] | All Other Consumer Excluding Home Equity and Second Mortgage [Member]
Total Nonperforming Loans	570	543
Nonperforming Financial Instruments [Member]
Nonaccrual Loans	1,765	3,055
Loans 90+ Days Past Due Still Accruing	13	2
Total Nonperforming Loans	1,778	3,057
Nonperforming Financial Instruments [Member] | Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Nonaccrual Loans	1,544	1,769
Loans 90+ Days Past Due Still Accruing	13
Total Nonperforming Loans	1,557	1,769
Nonperforming Financial Instruments [Member] | Real Estate Mortgage Portfolio Segment [Member] | Land Loan [Member]
Nonaccrual Loans	115	152
Loans 90+ Days Past Due Still Accruing
Total Nonperforming Loans	115	152
Nonperforming Financial Instruments [Member] | Real Estate Mortgage Portfolio Segment [Member] | Construction Loans [Member]
Nonaccrual Loans		521
Loans 90+ Days Past Due Still Accruing
Total Nonperforming Loans		521
Nonperforming Financial Instruments [Member] | Real Estate Mortgage Portfolio Segment [Member] | Commercial Real Estate Loan [Member]
Nonaccrual Loans		371
Loans 90+ Days Past Due Still Accruing
Total Nonperforming Loans		371
Nonperforming Financial Instruments [Member] | Commercial Portfolio Segment [Member]
Nonaccrual Loans	58	207
Loans 90+ Days Past Due Still Accruing
Total Nonperforming Loans	58	207
Nonperforming Financial Instruments [Member] | Consumer Portfolio Segment [Member] | Home Equity and Second Mortgage [Member]
Nonaccrual Loans		35
Loans 90+ Days Past Due Still Accruing
Total Nonperforming Loans		35
Nonperforming Financial Instruments [Member] | Consumer Portfolio Segment [Member] | All Other Consumer Excluding Home Equity and Second Mortgage [Member]
Nonaccrual Loans	48
Loans 90+ Days Past Due Still Accruing		2
Total Nonperforming Loans	$ 48	$ 2