Note 3 - Loans Receivable and Related Allowance for Loan Losses - Impaired Loans by Class (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Impaired loans with specific allowance, unpaid principal balance	$ 877	$ 458
Impaired loans with specific allowance, recorded investment	877	458
Related allowance	285	60
Impaired loans with specific allowance, average recorded investment	494	204
Impaired loans with specific allowance, interest income recognized in period	41	22
Impaired loans with specific allowance, cash basis interest recognized in period	41	15
Impaired loans with no specific allowance, unpaid principal balance	1,121	1,767
Impaired loans with no specific allowance, recorded investment	1,009	1,656
Impaired loans with no specific allowance, average recorded investment	1,374	1,549
Impaired loans with no specific allowance, interest income recognized in period	79	93
Impaired loans with no specific allowance, cash basis interest recognized in period	79	79
Residential Portfolio Segment [Member]
Impaired loans with specific allowance, unpaid principal balance	68	0
Impaired loans with specific allowance, recorded investment	68	0
Related allowance	1	0
Impaired loans with specific allowance, average recorded investment	28	43
Impaired loans with specific allowance, interest income recognized in period	3	0
Impaired loans with specific allowance, cash basis interest recognized in period	3	0
Impaired loans with no specific allowance, unpaid principal balance	338	440
Impaired loans with no specific allowance, recorded investment	226	329
Impaired loans with no specific allowance, average recorded investment	284	300
Impaired loans with no specific allowance, interest income recognized in period	3	7
Impaired loans with no specific allowance, cash basis interest recognized in period	3	7
Home Equity Loans and Lines of Credit [Member]
Impaired loans with specific allowance, unpaid principal balance	0	0
Impaired loans with specific allowance, recorded investment	0	0
Related allowance	0	0
Impaired loans with specific allowance, average recorded investment	0	2
Impaired loans with specific allowance, interest income recognized in period	0	0
Impaired loans with specific allowance, cash basis interest recognized in period	0	0
Impaired loans with no specific allowance, unpaid principal balance	4	3
Impaired loans with no specific allowance, recorded investment	4	3
Impaired loans with no specific allowance, average recorded investment	4	2
Impaired loans with no specific allowance, interest income recognized in period	0	0
Impaired loans with no specific allowance, cash basis interest recognized in period	0	0
Commercial Real Estate Portfolio Segment [Member]
Impaired loans with specific allowance, unpaid principal balance	559	380
Impaired loans with specific allowance, recorded investment	559	380
Related allowance	88	40
Impaired loans with specific allowance, average recorded investment	387	106
Impaired loans with specific allowance, interest income recognized in period	30	17
Impaired loans with specific allowance, cash basis interest recognized in period	30	11
Impaired loans with no specific allowance, unpaid principal balance	666	1,259
Impaired loans with no specific allowance, recorded investment	666	1,259
Impaired loans with no specific allowance, average recorded investment	990	1,167
Impaired loans with no specific allowance, interest income recognized in period	71	76
Impaired loans with no specific allowance, cash basis interest recognized in period	71	66
Commercial Portfolio Segment [Member]
Impaired loans with specific allowance, unpaid principal balance	250	78
Impaired loans with specific allowance, recorded investment	250	78
Related allowance	196	20
Impaired loans with specific allowance, average recorded investment	79	53
Impaired loans with specific allowance, interest income recognized in period	8	5
Impaired loans with specific allowance, cash basis interest recognized in period	8	4
Impaired loans with no specific allowance, unpaid principal balance	113	65
Impaired loans with no specific allowance, recorded investment	113	65
Impaired loans with no specific allowance, average recorded investment	96	80
Impaired loans with no specific allowance, interest income recognized in period	5	10
Impaired loans with no specific allowance, cash basis interest recognized in period	5	6
Consumer Portfolio Segment [Member]
Impaired loans with specific allowance, unpaid principal balance	0	0
Impaired loans with specific allowance, recorded investment	0	0
Related allowance	0	0
Impaired loans with specific allowance, average recorded investment	0	0
Impaired loans with specific allowance, interest income recognized in period	0	0
Impaired loans with specific allowance, cash basis interest recognized in period	0	0
Impaired loans with no specific allowance, unpaid principal balance	0	0
Impaired loans with no specific allowance, recorded investment	0	0
Impaired loans with no specific allowance, average recorded investment	0	0
Impaired loans with no specific allowance, interest income recognized in period	0	0
Impaired loans with no specific allowance, cash basis interest recognized in period	$ 0	$ 0

Amount of allowance for credit losses related to recorded investment.

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- Definition

Amount of average investment of impaired financing receivables for which there is no related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5258-111524

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-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524

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- Definition

Amount of interest income, recognized on accrual basis, on financing receivables that are recognized as impaired, for which there is no related allowance for credit losses.

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- Definition

Amount of interest income, recognized on cash basis, on financing receivables, for which there is no related allowance for credit losses and are recognized as impaired.

+ References

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- Definition

Amount of investment in impaired financing receivables for which there is no related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 14A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123577603&loc=SL6953550-111524

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- Definition

Amount of unpaid principal balance of impaired financing receivables for which there is no related allowance for credit losses.

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Amount of average investment of impaired financing receivables for which there is a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524

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-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5258-111524

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Amount of interest income, recognized on accrual basis, on financing receivables, for which there is a related allowance for credit losses and are recognized as impaired.

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Amount of interest income on financing receivables, for which there is a related allowance for credit losses, recognized on a cash-basis method of accounting that the financing receivables were impaired.

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Amount of investment in impaired financing receivables for which there is a related allowance for credit losses.

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Unpaid principal balance of impaired financing receivables for which there is a related allowance for credit losses.

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