Note 7 - Securities - Available-for-sale Securities With Unrealized Loss Positions (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Available-for-sale securities with unrealized loss positions, less than 12 months, fair value	$ 53,233	$ 13,548
Available-for-sale securities with unrealized loss positions, less than 12 months, unrealized losses	(336)	(25)
Available-for-sale securities with unrealized loss positions, 12 months or more, fair value	53,990	220,625
Available-for-sale securities with unrealized loss positions, 12 months or more, unrealized losses	(626)	(7,205)
Available-for-sale securities with unrealized loss positions, fair value	107,223	234,173
Available-for-sale securities, with unrealized loss positions, unrealized losses	(962)	(7,230)
Obligations of States and Political Subdivisions Tax Exempt [Member]
Available-for-sale securities with unrealized loss positions, less than 12 months, fair value	6,429	5,084
Available-for-sale securities with unrealized loss positions, less than 12 months, unrealized losses	(38)	(11)
Available-for-sale securities with unrealized loss positions, 12 months or more, fair value	0	32,684
Available-for-sale securities with unrealized loss positions, 12 months or more, unrealized losses	0	(1,190)
Available-for-sale securities with unrealized loss positions, fair value	6,429	37,768
Available-for-sale securities, with unrealized loss positions, unrealized losses	(38)	(1,201)
Obligations of States and Political Subdivisions Taxable [Member]
Available-for-sale securities with unrealized loss positions, less than 12 months, fair value	5,624	980
Available-for-sale securities with unrealized loss positions, less than 12 months, unrealized losses	(68)	(2)
Available-for-sale securities with unrealized loss positions, 12 months or more, fair value	161	11,418
Available-for-sale securities with unrealized loss positions, 12 months or more, unrealized losses	(2)	(125)
Available-for-sale securities with unrealized loss positions, fair value	5,785	12,398
Available-for-sale securities, with unrealized loss positions, unrealized losses	(70)	(127)
Residential Pass-Through Securities [Member]
Available-for-sale securities with unrealized loss positions, less than 12 months, fair value	9,771	5,592
Available-for-sale securities with unrealized loss positions, less than 12 months, unrealized losses	(35)	(4)
Available-for-sale securities with unrealized loss positions, 12 months or more, fair value	14,787	42,309
Available-for-sale securities with unrealized loss positions, 12 months or more, unrealized losses	(102)	(1,426)
Available-for-sale securities with unrealized loss positions, fair value	24,558	47,901
Available-for-sale securities, with unrealized loss positions, unrealized losses	(137)	(1,430)
Residential Collateralized Mortgage Obligations [Member]
Available-for-sale securities with unrealized loss positions, less than 12 months, fair value	31,409	1,892
Available-for-sale securities with unrealized loss positions, less than 12 months, unrealized losses	(195)	(8)
Available-for-sale securities with unrealized loss positions, 12 months or more, fair value	30,535	101,662
Available-for-sale securities with unrealized loss positions, 12 months or more, unrealized losses	(415)	(3,282)
Available-for-sale securities with unrealized loss positions, fair value	61,944	103,554
Available-for-sale securities, with unrealized loss positions, unrealized losses	(610)	(3,290)
Commercial Mortgage Backed Securities [Member]
Available-for-sale securities with unrealized loss positions, less than 12 months, fair value	0	0
Available-for-sale securities with unrealized loss positions, less than 12 months, unrealized losses	0	0
Available-for-sale securities with unrealized loss positions, 12 months or more, fair value	8,507	32,552
Available-for-sale securities with unrealized loss positions, 12 months or more, unrealized losses	(107)	(1,182)
Available-for-sale securities with unrealized loss positions, fair value	8,507	32,552
Available-for-sale securities, with unrealized loss positions, unrealized losses	$ (107)	$ (1,182)

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=118955579&loc=SL82922890-210455

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27337-111563

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-Name Accounting Standards Codification
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