Note 10 - Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income (Loss) by Component (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Balance				$ 74,338
Total other comprehensive income		$ 720	$ 1,400	3,133	$ 4,917
Balance		78,148	74,153	78,148	74,153
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Balance	[1]	3,531	(183)	1,107	(3,686)
Other comprehensive income (loss) before reclassification	[1]	738	1,393	3,176	4,861
Amount reclassified from accumulated other comprehensive income or loss		0	0	(14)	35
Total other comprehensive income		738	1,393	3,162	4,896
Balance	[1]	4,269	1,210	4,269	1,210
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member]
Balance	[1]	50	44	61	30
Other comprehensive income (loss) before reclassification	[1]	(18)	7	(29)	21
Amount reclassified from accumulated other comprehensive income or loss		0	0	0	0
Total other comprehensive income		(18)	7	(29)	21
Balance	[1]	$ 32	$ 51	$ 32	$ 51

[1] All amounts are net of tax. Amounts in parentheses indicate debits.