Note 3 - Securities - Securities in an Unrealized Loss Position (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Available-for-sale securities, less than 12 months, fair value	$ 230,582	$ 83,309
Available-for-sale securities, less than 12 months, unrealized losses	(4,535)	(288)
Available-for-sale securities, 12 months or more, fair value	1,574	2,794
Available-for-sale securities, 12 months or more, unrealized losses	(16)	(14)
Available-for-sale securities, fair value	232,156	86,103
Available-for-sale securities, unrealized losses	(4,551)	(302)
US Government Agencies Debt Securities [Member]
Available-for-sale securities, less than 12 months, fair value	2,934	0
Available-for-sale securities, less than 12 months, unrealized losses	(89)	0
Available-for-sale securities, 12 months or more, fair value	677	1,615
Available-for-sale securities, 12 months or more, unrealized losses	(7)	(8)
Available-for-sale securities, fair value	3,611	1,615
Available-for-sale securities, unrealized losses	(96)	(8)
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale securities, less than 12 months, fair value	47,968	7,291
Available-for-sale securities, less than 12 months, unrealized losses	(1,655)	(29)
Available-for-sale securities, 12 months or more, fair value	438	0
Available-for-sale securities, 12 months or more, unrealized losses	(2)	0
Available-for-sale securities, fair value	48,406	7,291
Available-for-sale securities, unrealized losses	(1,657)	(29)
Residential Mortgage Backed Securities and Collateralized Mortgage Obligations [Member]
Available-for-sale securities, less than 12 months, fair value	157,530	68,512
Available-for-sale securities, less than 12 months, unrealized losses	(2,355)	(241)
Available-for-sale securities, 12 months or more, fair value	459	249
Available-for-sale securities, 12 months or more, unrealized losses	(7)	(5)
Available-for-sale securities, fair value	157,989	68,761
Available-for-sale securities, unrealized losses	(2,362)	(246)
Commercial Mortgage Backed Securities [Member]
Available-for-sale securities, less than 12 months, fair value	22,150	5,400
Available-for-sale securities, less than 12 months, unrealized losses	(436)	(18)
Available-for-sale securities, 12 months or more, fair value	0	0
Available-for-sale securities, 12 months or more, unrealized losses	0	0
Available-for-sale securities, fair value	22,150	5,400
Available-for-sale securities, unrealized losses	$ (436)	(18)
Asset-backed Securities [Member]
Available-for-sale securities, less than 12 months, fair value		2,106
Available-for-sale securities, less than 12 months, unrealized losses		0
Available-for-sale securities, 12 months or more, fair value		930
Available-for-sale securities, 12 months or more, unrealized losses		(1)
Available-for-sale securities, fair value		3,036
Available-for-sale securities, unrealized losses		$ (1)

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=121582814&loc=SL82922890-210455

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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