Note 5 - Accounting for Certain Loans Acquired - Carrying Amount of Certain Loans Acquired in Transfer (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Certain loans acquired in transfer	$ 2,928	$ 3,311
Carrying amount, net of fair value adjustment	2,542	2,835	$ 3,173
Commercial Real Estate Portfolio Segment [Member]
Certain loans acquired in transfer	2,751	3,069
Carrying amount, net of fair value adjustment	2,410	2,651	2,782
Commercial Portfolio Segment [Member]
Certain loans acquired in transfer	177	242
Carrying amount, net of fair value adjustment	132	184	$ 216
Consumer and Other Loans [Member]
Certain loans acquired in transfer	$ 0	$ 0

The undiscounted sum of all amounts, including amounts deemed principal, interest, fees, penalties, and other under the loan, owed to the investor at the reporting date, whether or not currently due and whether or not any such amounts have been written or charged off by the investor. This relates to loans not accounted for as debt securities, with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 15
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=121585399&loc=d3e13503-111538

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=121614798&loc=d3e15032-111544

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant