Note 3 - Accumulated Other Comprehensive Income (Loss) - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Balance	$ 392,995	$ 397,108	$ 404,482	$ 407,774	$ 386,730	$ 386,803	$ 404,482	$ 386,803
Other comprehensive income (loss), net of tax	1,093	(385)	604	(1,360)	882	391	1,312	(87)
Balance	402,986	392,995	397,108	400,299	407,774	386,730	402,986	400,299
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Balance	633	835	1,224	2,166	1,088	822	1,224	822
Change in unrealized gains (losses) during the period	(257)	(273)	(501)	(802)	1,417	455
Net losses reclassified into income during the period	5	8	8	140	(20)	(110)
Income tax benefit (provision)	60	63	104	151	(319)	(79)
Other comprehensive income (loss), net of tax	(192)	(202)	(389)	(511)	1,078	266
Balance	441	633	835	1,655	2,166	1,088	441	1,655
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Balance	(898)	(715)	(1,708)	269	465	340	(1,708)	340
Change in unrealized gains (losses) during the period	1,367	(394)	1,092	(931)	(117)	386
Net losses reclassified into income during the period	318	152	192	(170)	(137)	(224)
Income tax benefit (provision)	(400)	59	(291)	252	58	(37)
Other comprehensive income (loss), net of tax	1,285	(183)	993	(849)	(196)	125
Balance	387	(898)	(715)	(580)	269	465	387	(580)
AOCI Attributable to Parent [Member]
Balance	(265)	120	(484)	2,435	1,553	1,162	(484)	1,162
Change in unrealized gains (losses) during the period	1,110	(667)	591	(1,733)	1,300	841
Net losses reclassified into income during the period	323	160	200	(30)	(157)	(334)
Income tax benefit (provision)	(340)	122	(187)	403	(261)	(116)
Other comprehensive income (loss), net of tax	1,093	(385)	604	(1,360)	882	391
Balance	$ 828	$ (265)	$ 120	$ 1,075	$ 2,435	$ 1,553	$ 828	$ 1,075