Note 3 - Loans and Allowance for Loan Losses - Allowance Related to Troubled Debt Restructurings (Details) - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Related allowance	$ 490,000	$ 1,578,000
Commercial Portfolio Segment [Member]
Related allowance	107,000	1,184,000
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Related allowance	74,000	202,000
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	31,000	982,000
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Related allowance	2,000	0
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Related allowance	0	0
Retail Portfolio Segment [Member]
Related allowance	383,000	394,000
Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Related allowance	230,000	311,000
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Related allowance	$ 153,000	$ 83,000