Note 8 - Components of Accumulated Other Comprehensive Income (Loss) - Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Balance	$ 195,781	$ 183,848	$ 183,726	$ 190,238
Balance	202,194	187,988	202,194	187,988
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Balance	9,518	2,457	76	(5,072)
Unrealized holding gain (loss) on available for sale securities, net of tax	2,256	544	11,763	8,089
Reclassification adjustment, net of tax	(11)	(128)	(76)	(144)
Balance	11,763	2,873	11,763	2,873
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Balance		(7,013)	(8,582)	(7,013)
Balance	(8,582)	(7,013)	(8,582)	(7,013)
AOCI Attributable to Parent [Member]
Balance	936	(4,556)	(8,506)	(12,085)
Unrealized holding gain (loss) on available for sale securities, net of tax	2,256	544	11,763	8,089
Reclassification adjustment, net of tax	(11)	(128)	(76)	(144)
Balance	$ 3,181	$ (4,140)	$ 3,181	$ (4,140)