Note 7 - Components of Accumulated Other Comprehensive Income (Loss) - Components of Accumulated Other Comprehensive Income (Loss) (Details) (Parentheticals) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Unrealized holding gain (loss) on available for sale securities, tax	$ (905)	$ 601	$ (2,254)	$ 3,127
Reclassification adjustment for gain included in net income, taxes		(3)	(1)	(20)
AOCI Attributable to Parent [Member]
Unrealized holding gain (loss) on available for sale securities, tax	$ (905)	601	(2,254)	3,127
Reclassification adjustment for gain included in net income, taxes		$ (3)	$ (1)	$ (20)

Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income (loss).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=124509347&loc=d3e640-108580

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=124431353&loc=SL124442407-227067

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 17A
-URI http://asc.fasb.org/extlink&oid=124509347&loc=SL34724391-108580

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