Note 3 - Loans and Allowance for Loan Losses - Allowance Related to Troubled Debt Restructurings (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Related allowance	$ 598,000	$ 467,000
Commercial Portfolio Segment [Member]
Related allowance	406,000	120,000
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Related allowance	311,000	53,000
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	89,000	59,000
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Related allowance	6,000	8,000
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Related allowance	0	0
Retail Portfolio Segment [Member]
Related allowance	192,000	347,000
Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Related allowance	113,000	202,000
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Related allowance	$ 79,000	$ 145,000