Note 17 - Derivative Financial Instruments (Details Textual) - Cash Flow Hedging [Member] - Designated as Hedging Instrument [Member] - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2016	Dec. 31, 2015
Derivative, Notional Amount	$ 30,000
Interest Rate Swap, Maturing December 6, 2021 [Member]
Derivative, Notional Amount	10,000	$ 10,000
Interest Rate Swap, Maturing December 6, 2020 [Member]
Derivative, Notional Amount	$ 20,000		$ 20,000