Note 4 - Loans and Allowance for Loan Losses - Allowance Related to Troubled Debt Restructurings (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Related allowance	$ 1,578,000	$ 936,000
Commercial Portfolio Segment [Member]
Related allowance	1,184,000	489,000
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Related allowance	202,000	126,000
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Related allowance	0	0
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Related allowance	982,000	363,000
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Related allowance	0	0
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Related allowance	0	0
Retail Portfolio Segment [Member]
Related allowance	394,000	447,000
Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Related allowance	311,000	337,000
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Related allowance	$ 83,000	$ 110,000