Note 10 - Derivative Financial Instruments and Hedging Transactions (Details Textual) - USD ($)
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Other Income [Member] | Fair Value Hedging [Member]      
Derivative, Net Hedge Ineffectiveness Gain (Loss) $ 45,000 $ (23,000) $ (128,000)