Note 4 - Allowance for Loan Losses (Details Textual)	3 Months Ended	12 Months Ended
	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Loans Not Classified as Impaired [Member] | Substandard [Member]
Loans and Leases Receivable, Gross	$ 17,840,000			$ 7,200,000
Loans and Leases Receivable, Allowance	1,170			596,000
Substandard [Member]
Loans and Leases Receivable, Gross	36,826,000	$ 32,397,000
Loan Balance For Reviewing High Risk Loans Minimum	$ 250,000
Allowance for Loan Losses, Loss History Period, Number of Quarters	12	8
Allowance for Loan Losses, Increase in Calculation for Call Code Segments, Change in Method of Calculation	$ 718,000
Allowance for Credit Losses, Change in Method of Calculating Impairment			$ 1,621,000
Loans and Leases Receivable, Gross	754,261,000	$ 758,636,000		753,634,000
Loans and Leases Receivable, Allowance	$ 9,549,000	$ 8,604,000		8,377,000	$ 8,802,000
Impaired Financing Receivable, Number of Loans Below Review Threshold	156
Impaired Financing Receivable Recorded Investment Below Review Threshold	$ 3,600,000			$ 4,400,000