Note 4 - Allowance for Loan Losses (Details Textual)	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)
Loans Not Classified as Impaired [Member] | Substandard [Member]
Loans and Leases Receivable, Gross			$ 12,640,000	$ 8,600,000
Loans and Leases Receivable, Allowance			791,000	569,000
Substandard [Member]
Loans and Leases Receivable, Gross		$ 32,397,000	32,380,000
Allowance for Loan Losses, Loss History Period, Number of Quarters	16	8
Loans and Leases Receivable, Gross		$ 758,636,000	764,209,000	760,078,000
Loans and Leases Receivable, Allowance		$ 8,604,000	9,390,000	$ 8,480,000	$ 8,802,000
Loan Balance For Reviewing High Risk Loans Minimum			$ 250,000
Impaired Financing Receivable, Number of Loans Below Review Threshold			165	156
Impaired Financing Receivable Recorded Investment Below Review Threshold			$ 3,800,000	$ 4,300,000