Note 4 - Investment Securities (Details Textual) - USD ($)	Jun. 30, 2016	Dec. 31, 2015
Call Option [Member]
Available-for-sale Securities, Amortized Cost Basis	$ 65,900,000	$ 68,400,000
Callable Within One Year [Member]
Available-for-sale Securities, Amortized Cost Basis	24,900,000	26,100,000
Cash, FDIC Insured Amount	250,000	250,000
Available-for-sale Securities Pledged as Collateral	107,700,000	119,100,000
Securities Sold under Agreements to Repurchase, Asset	15,000,000	12,100,000
Available-for-sale Securities, Amortized Cost Basis	$ 188,579,000	$ 197,960,000