Note 14 - Accumulated Other Comprehensive Income (Loss) - Components of Accumulated Other Comprehensive Income, Net of Tax (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020		Jun. 30, 2019
Balance	$ 411,606	$ 333,102	$ 428,819	[1]	$ 332,857
Other comprehensive income (loss), net	31	352	398		1,048
Balance	415,830	333,686	415,830		333,686
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Balance	1,509	677	866		(285)
Other comprehensive income (loss) before reclassifications	(45)	262	902		1,224
Reclassified from AOCI	0	34	(304)		34
Other comprehensive income (loss), net	(45)	296	598		1,258
Balance	1,464	973	1,464		973
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Balance	(2,648)	(1,410)	(2,372)		(1,144)
Other comprehensive income (loss) before reclassifications	0	0	(353)		(320)
Reclassified from AOCI	76	56	153		110
Other comprehensive income (loss), net	76	56	(200)		(210)
Balance	(2,572)	(1,354)	(2,572)		(1,354)
AOCI Attributable to Parent [Member]
Balance	(1,139)	(733)	(1,506)		(1,429)
Other comprehensive income (loss) before reclassifications	(45)	262	549		904
Reclassified from AOCI	76	90	(151)		144
Other comprehensive income (loss), net	31	352	398		1,048
Balance	$ (1,108)	$ (381)	$ (1,108)		$ (381)

[1] Derived from audited financial statements