Note 3 - Securities - Sales of Securities (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Proceeds from sales of investment securities	$ 18,338	$ 1,107	$ 85,740	$ 20,505
Gross realized gains on sales of securities	139	4	399	156
Gross realized losses on sales of securities	(106)		(274)	(116)
Gain on sales of investment securities, net	33	4	125	40
US Government Agencies Debt Securities [Member]
Gross realized gains on sales of securities	6		39
Gross realized losses on sales of securities			(4)
US States and Political Subdivisions Debt Securities [Member]
Gross realized gains on sales of securities	115	4	294	156
Gross realized losses on sales of securities	(12)		(90)	(71)
Residential Mortgage Backed Securities and Collateralized Mortgage Obligations [Member]
Gross realized gains on sales of securities	16		64
Gross realized losses on sales of securities	(64)		(149)
Commercial Mortgage Backed Securities [Member]
Gross realized gains on sales of securities	2		2
Gross realized losses on sales of securities	(30)		(31)
Asset-backed Securities [Member]
Gross realized losses on sales of securities				$ (45)

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)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27357-111563

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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
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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-Paragraph 11
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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
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