Note 6 - Loans and Allowance for Loan Losses (Details Textual)	9 Months Ended	12 Months Ended
	Sep. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)
Real Estate [Member]
Percentage of Loan Portfolio	56.80%	58.00%
Related Party Loan [Member]
Loans and Leases Receivable, Related Parties	$ 2,800,000	$ 2,900,000
Loans and Leases Receivable, Related Parties, Proceeds	100,000	$ 200,000
Minimum [Member]
Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest	$ 500,000
Number of Portfolio Segments	8
Number of Loans, Related Party	1	0
Financing Receivable, Modifications, Subsequent Default, Number of Contracts	0	0
Minimum Modified Loan Term Period		0 years
Financing Receivable, Restructuring, Recorded Investment Restored to Accrual Status	$ 287,000	$ 0
Loans Receivable with Variable Rates of Interest	89,100,000	55,300,000
Loans Receivable with Fixed Rates of Interest	143,700,000	119,600,000
Financing Receivable, Recorded Investment, Nonaccrual Status	2,266,000	3,102,000
Loans and Leases Receivable, Impaired, Interest Lost on Nonaccrual Loans	30,000	100,000
Interest Income Recorded	$ 4,000	300,000
Troubled Debt Restructuring, Modified Period Term	180 days
Financing Receivable, Restructuring Recorded Investment With Nonaccrual Status	$ 200,000	1,500,000
Loans Modified in a Troubled Debt Restructuring, Individually Evaluated for Impairment, Principal Balance, Threshold	500,000
Allowance for Credit Losses, Change in Method of Calculating Impairment	$ 5,000	$ 1,000