Note 8 - Components of Accumulated Other Comprehensive Loss - Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Balance	$ 181,228	$ 185,537	$ 190,238	$ 184,896
Unrealized holding gain on securities transferred from held to maturity to available for sale, net of tax		891		891
Balance	183,848	185,851	183,848	185,851
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Balance			(5,072)	(3,704)
Unrealized holding gain (loss) on available for sale securities, net of tax			7,545	(3,237)
Unrealized holding gain on securities transferred from held to maturity to available for sale, net of tax				891
Reclassification adjustment, net of tax			(16)
Balance	2,457	(6,050)	2,457	(6,050)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Balance			(7,013)	(5,991)
Unrealized holding gain (loss) on available for sale securities, net of tax			0	0
Unrealized holding gain on securities transferred from held to maturity to available for sale, net of tax
Reclassification adjustment, net of tax			0
Balance	(7,013)	(5,991)	(7,013)	(5,991)
AOCI Attributable to Parent [Member]
Balance	(7,541)	(12,350)	(12,085)	(9,695)
Unrealized holding gain (loss) on available for sale securities, net of tax			7,545	(3,237)
Unrealized holding gain on securities transferred from held to maturity to available for sale, net of tax				891
Reclassification adjustment, net of tax			(16)
Balance	$ (4,556)	$ (12,041)	$ (4,556)	$ (12,041)