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Note 5 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Restructurings By Class (Details) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Number of contracts		0	1	13
Pre-modification outstanding principal balance			$ 100	$ 4,213
Post-modification outstanding principal balance			$ 100	$ 4,213	[1]
Residential Portfolio Segment [Member] | Equity Lines [Member]
Number of contracts			1
Pre-modification outstanding principal balance			$ 100
Post-modification outstanding principal balance			$ 100
Real Estate Construction Portfolio Segment[Member] | Construction Loans [Member]
Number of contracts				2
Pre-modification outstanding principal balance				$ 2,882
Post-modification outstanding principal balance	[1]			$ 2,882
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate, Owner Occupied [Member]
Number of contracts				2
Pre-modification outstanding principal balance				$ 715
Post-modification outstanding principal balance	[1]			$ 715
Consumer Real Estate Portfolio Segment [Member] | Closed End First Liens [Member]
Number of contracts				1
Pre-modification outstanding principal balance				$ 22
Post-modification outstanding principal balance	[1]			$ 22
Consumer Real Estate Portfolio Segment [Member] | Investor Owned Residential Real Estate [Member]
Number of contracts				8
Pre-modification outstanding principal balance				$ 594
Post-modification outstanding principal balance	[1]			$ 594
[1] Post-modification outstanding recorded investment considers amounts immediately following the modification. Amounts do not reflect balances at the end of the period.

X

- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953676-111524

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- Definition

Amount, after troubled debt restructuring, of modified financing receivable.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953676-111524

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- Definition

Amount, before troubled debt restructuring, of financing receivable to be modified.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953676-111524

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