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Note 3 - Loans and Allowance for Loan Losses - Loans Modified as Troubled Debt Restructurings (Details)	3 Months Ended
	Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)
Number of Contracts	3	17
Pre- Modification Recorded Principal Balance	$ 130,000	$ 10,265,000
Post- Modification Recorded Principal Balance	$ 129,000	$ 10,847,000
Commercial Portfolio Segment [Member]
Number of Contracts	1	14
Pre- Modification Recorded Principal Balance	$ 23,000	$ 10,200,000
Post- Modification Recorded Principal Balance	$ 22,000	$ 10,795,000
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Number of Contracts	1	6
Pre- Modification Recorded Principal Balance	$ 23,000	$ 6,539,000
Post- Modification Recorded Principal Balance	$ 22,000	$ 6,536,000
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Number of Contracts	0	0
Pre- Modification Recorded Principal Balance	$ 0	$ 0
Post- Modification Recorded Principal Balance	$ 0	$ 0
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Number of Contracts	0	8
Pre- Modification Recorded Principal Balance	$ 0	$ 3,661,000
Post- Modification Recorded Principal Balance	$ 0	$ 4,259,000
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Number of Contracts	0	0
Pre- Modification Recorded Principal Balance	$ 0	$ 0
Post- Modification Recorded Principal Balance	$ 0	$ 0
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Number of Contracts	0	0
Pre- Modification Recorded Principal Balance	$ 0	$ 0
Post- Modification Recorded Principal Balance	$ 0	$ 0
Retail Portfolio Segment [Member]
Number of Contracts	2	3
Pre- Modification Recorded Principal Balance	$ 107,000	$ 65,000
Post- Modification Recorded Principal Balance	$ 107,000	$ 52,000
Retail Portfolio Segment [Member] | Home Equity and Other [Member]
Number of Contracts	1	3
Pre- Modification Recorded Principal Balance	$ 71,000	$ 65,000
Post- Modification Recorded Principal Balance	$ 71,000	$ 52,000
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Number of Contracts	1	0
Pre- Modification Recorded Principal Balance	$ 36,000	$ 0
Post- Modification Recorded Principal Balance	$ 36,000	$ 0

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

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+ 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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