Note 17 - Components of Accumulated Other Comprehensive Income (Loss) - Components of Accumulated Other Comprehensive Loss (Details) (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net pension gain (loss) arising during the period, taxes	$ 115	$ 132	$ (597)
Less amortization of prior service cost included in net periodic pension cost, tax	(38)	(38)	(38)
Unrealized holding gain (loss) on available for sale securities, tax	(296)	431	571
AOCI Attributable to Parent [Member]
Reclassification adjustment for gain included in net income, taxes	(4)	(65)	(12)
Net pension gain (loss) arising during the period, taxes	115	132	(597)
Less amortization of prior service cost included in net periodic pension cost, tax	(38)	(38)	$ (38)
Unrealized holding gain (loss) on available for sale securities, tax	$ 296	$ (431)