Note 7 - Components of Accumulated Other Comprehensive Income (Loss) - Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Balance	$ 200,607	$ 183,726
Balance	189,069	191,559
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Balance	13,167	76
Unrealized holding gain (loss) on available for sale securities, net of tax	(12,309)	3,870
Reclassification adjustment, net of tax	(4)	(16)
Balance	854	3,930
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Balance	(10,147)	(8,582)
Balance	(10,147)	(8,582)
AOCI Attributable to Parent [Member]
Balance	3,020	(8,506)
Unrealized holding gain (loss) on available for sale securities, net of tax	(12,309)	3,870
Reclassification adjustment, net of tax	(4)	(16)
Balance	$ (9,293)	$ (4,652)