Note 16 - Components of Accumulated Other Comprehensive Income (Loss) - Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Balance	$ 190,238	$ 184,896	$ 178,263
Less amortization of prior service cost included in net periodic pension cost, net of tax	(87)	(86)	(71)
Reclassification of stranded tax effects from change in tax rate
Transfer from held-to-maturity to available-for-sale securities, net of tax $237		891
Balance	183,726	190,238	184,896
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Balance	(5,072)	(3,704)	(3,588)
Unrealized holding gain (loss) on available for sale securities, net of tax	5,595	(2,246)	546
Reclassification adjustment, net of tax	(447)	(13)	(6)
Net pension gain (loss) arising during the period, net of tax
Less amortization of prior service cost included in net periodic pension cost, net of tax
Reclassification of stranded tax effects from change in tax rate			(656)
Transfer from held-to-maturity to available-for-sale securities, net of tax $237		891
Balance	76	(5,072)	(3,704)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Balance	(7,013)	(5,991)	(5,071)
Unrealized holding gain (loss) on available for sale securities, net of tax		0	0
Reclassification adjustment, net of tax			0
Net pension gain (loss) arising during the period, net of tax	(1,482)	(936)	213
Less amortization of prior service cost included in net periodic pension cost, net of tax	(87)	(86)	(71)
Reclassification of stranded tax effects from change in tax rate			(1,062)
Transfer from held-to-maturity to available-for-sale securities, net of tax $237
Balance	(8,582)	(7,013)	(5,991)
AOCI Attributable to Parent [Member]
Balance	(12,085)	(9,695)	(8,659)
Unrealized holding gain (loss) on available for sale securities, net of tax	5,595	(2,246)	546
Reclassification adjustment, net of tax	(447)	(13)	(6)
Net pension gain (loss) arising during the period, net of tax	(1,482)	(936)	213
Less amortization of prior service cost included in net periodic pension cost, net of tax	(87)	(86)	(71)
Reclassification of stranded tax effects from change in tax rate			(1,718)
Transfer from held-to-maturity to available-for-sale securities, net of tax $237		891
Balance	$ (8,506)	$ (12,085)	$ (9,695)