Note 3 - Securities - Sales of Securities (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Proceeds from sales of investment securities	$ 11,890	$ 29,339
Gross realized gains on sales of securities	53	168
Gross realized losses on sales of securities	(46)	(84)
Gain on sale of investment securities, net	7	84
US States and Political Subdivisions Debt Securities [Member]
Gross realized gains on sales of securities	0	48
Gross realized losses on sales of securities	0	(4)
Residential Mortgage Backed Securities and Collateralized Mortgage Obligations [Member]
Gross realized gains on sales of securities	53	84
Gross realized losses on sales of securities	(46)	(80)
Commercial Mortgage Backed Securities [Member]
Gross realized gains on sales of securities	$ 0	$ 36

Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (a)
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Amount of realized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (a)
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-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 11
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