Note 9 - Derivative Instruments and Hedging Activities - Effect of Derivative and Hedging Activity, on Consolidated Statements of Income (Details) - Interest Rate Swap [Member] - Interest and Fees on Loans [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Derivative expense	$ 8	$ 19	$ 21	$ 41
Designated as Hedging Instrument [Member]
Derivative expense	$ 8	$ 19	$ 21	$ 41