Note 3 - Loans and Allowance for Loan Losses - Allowance Related to Troubled Debt Restructurings (Details) - USD ($)	Sep. 30, 2017	Dec. 31, 2016
Related allowance	$ 466,000	$ 694,000
Commercial Portfolio Segment [Member]
Related allowance	276,000	642,000
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Related allowance	111,000	9,000
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Related allowance	6,000	28,000
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Related allowance	157,000	100,000
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Related allowance	2,000	247,000
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Related allowance	0	258,000
Retail Portfolio Segment [Member]
Related allowance	190,000	52,000
Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Related allowance	187,000	48,000
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Related allowance	$ 3,000	$ 4,000