Note 5 - Loans and Allowance for Loan Losses - Impaired Loans (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Valuation allowance	$ 1,289		$ 1,094
Loans recorded balance	11,398		11,968
Loans unpaid principal	12,631		13,201
Loans average investment in impaired loans	11,112	$ 18,075
Loans interest income recognized	12	5
Residential Portfolio Segment [Member] \| Real Estate Residential, One To Four Family Units [Member]
Loans without a specific valuation allowance, recorded balance	1,086		1,392
Loans without a specific valuation allowance, unpaid principal	1,086		1,392
Loans with a specific valuation allowance, recorded balance	1,294		1,221
Loans with a specific valuation allowance, unpaid principal	1,294		1,221
Valuation allowance	249		197
Loans recorded balance	2,380		2,613
Loans unpaid principal	2,380		2,613
Loans without a specific valuation allowance, average investment in impaired loans	1,096	1,046
Loans without a specific valuation allowance, interest income recognized	0	1
Loans with a specific valuation allowance, average investment in impaired loans	1,248	1,970
Loans with a specific valuation allowance, interest income recognized	0	0
Loans average investment in impaired loans	2,344	3,016
Loans interest income recognized	0	1
Residential Portfolio Segment [Member] \| Real Estate Residential, Multi Family Units [Member]
Loans without a specific valuation allowance, recorded balance	0		0
Loans without a specific valuation allowance, unpaid principal	0		0
Valuation allowance	0		0
Loans recorded balance	0		0
Loans unpaid principal	0		0
Loans without a specific valuation allowance, average investment in impaired loans	0	5,933
Loans without a specific valuation allowance, interest income recognized	0	0
Loans with a specific valuation allowance, average investment in impaired loans	0	0
Loans with a specific valuation allowance, interest income recognized	0	0
Loans average investment in impaired loans	0	5,933
Loans interest income recognized	0	0
Residential Portfolio Segment [Member] \| Construction Loans [Member]
Loans without a specific valuation allowance, average investment in impaired loans	0	0
Loans without a specific valuation allowance, interest income recognized	0	0
Loans with a specific valuation allowance, average investment in impaired loans	4,272	3,866
Loans with a specific valuation allowance, interest income recognized	0	0
Loans average investment in impaired loans	4,272	3,866
Loans interest income recognized	0	0
Real Estate, Construction [Member]
Loans without a specific valuation allowance, recorded balance	0		0
Loans without a specific valuation allowance, unpaid principal	0		0
Loans with a specific valuation allowance, recorded balance	4,437		4,742
Loans with a specific valuation allowance, unpaid principal	5,670		5,975
Valuation allowance	626		553
Loans recorded balance	4,437		4,742
Loans unpaid principal	5,670		5,975
Commercial Real Estate Portfolio Segment [Member]
Loans without a specific valuation allowance, recorded balance	3,281		3,199
Loans without a specific valuation allowance, unpaid principal	3,281		3,199
Loans with a specific valuation allowance, recorded balance	249		162
Loans with a specific valuation allowance, unpaid principal	249		162
Valuation allowance	95		24
Loans recorded balance	3,530		3,361
Loans unpaid principal	3,530		3,361
Loans without a specific valuation allowance, average investment in impaired loans	3,104	3,353
Loans without a specific valuation allowance, interest income recognized	2	4
Loans with a specific valuation allowance, average investment in impaired loans	240	657
Loans with a specific valuation allowance, interest income recognized	0	0
Loans average investment in impaired loans	3,344	4,010
Loans interest income recognized	2	4
Commercial Portfolio Segment [Member]
Loans without a specific valuation allowance, recorded balance	128		33
Loans without a specific valuation allowance, unpaid principal	128		33
Loans with a specific valuation allowance, recorded balance	695		999
Loans with a specific valuation allowance, unpaid principal	695		999
Valuation allowance	301		299
Loans recorded balance	823		1,032
Loans unpaid principal	823		1,032
Loans without a specific valuation allowance, average investment in impaired loans	34	161
Loans without a specific valuation allowance, interest income recognized	0	0
Loans with a specific valuation allowance, average investment in impaired loans	862	702
Loans with a specific valuation allowance, interest income recognized	0	0
Loans average investment in impaired loans	896	863
Loans interest income recognized	0	0
Consumer and Other Loans [Member]
Loans without a specific valuation allowance, recorded balance	109		70
Loans without a specific valuation allowance, unpaid principal	109		70
Loans with a specific valuation allowance, recorded balance	119		150
Loans with a specific valuation allowance, unpaid principal	119		150
Valuation allowance	18		21
Loans recorded balance	228		220
Loans unpaid principal	228		$ 220
Consumer Portfolio Segment [Member]
Loans without a specific valuation allowance, average investment in impaired loans	111	268
Loans without a specific valuation allowance, interest income recognized	10	0
Loans with a specific valuation allowance, average investment in impaired loans	145	119
Loans with a specific valuation allowance, interest income recognized	0	0
Loans average investment in impaired loans	256	387
Loans interest income recognized	$ 10	$ 0

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524

Reference 2: 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=121611835&loc=d3e5258-111524

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5258-111524

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-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524

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