Note 3 - Loans and Allowance for Loan Losses - Allowance Related to Troubled Debt Restructurings (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Related allowance	$ 1,034,000	$ 936,000
Commercial Portfolio Segment [Member]
Related allowance	690,000	489,000
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Related allowance	382,000	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	308,000	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	344,000	447,000
Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Related allowance	258,000	337,000
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Related allowance	$ 86,000	$ 110,000