Note 3 - Loans and Allowance for Loan Losses - Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Recorded investment with no allowance	$ 2,798		$ 2,798		$ 3,168
Unpaid principal balance with no allowance	2,910		2,910		3,338
Average recorded investment with no allowance	2,902	$ 3,098	2,990	$ 2,917
Interest income recognized with no allowance	18	21	35	38
Recorded investment with allowance	340		340
Unpaid principal balance with allowance	348		348
Related allowance	12		12		0
Average recorded investment with allowance	316	243	210	225
Interest income recognized with allowance	0	0	0	0
Recorded investment	3,138		3,138		3,168
Unpaid principal balance	3,258		3,258		3,338
Average recorded investment	3,218	3,341	3,200	3,142
Interest income recognized	18	21	35	38
Real Estate Mortgage Portfolio Segment [Member] \| Residential Loan [Member]
Recorded investment with no allowance	1,659		1,659		1,728
Unpaid principal balance with no allowance	1,762		1,762		1,902
Average recorded investment with no allowance	1,769	1,622	1,755	1,660
Interest income recognized with no allowance	6	5	12	11
Recorded investment with allowance	0		0		0
Unpaid principal balance with allowance	0		0		0
Related allowance	0		0		0
Average recorded investment with allowance	0	144	0	159
Interest income recognized with allowance	0	0	0	0
Recorded investment	1,659		1,659		1,728
Unpaid principal balance	1,762		1,762		1,902
Average recorded investment	1,769	1,766	1,755	1,819
Interest income recognized	6	5	12	11
Real Estate Mortgage Portfolio Segment [Member] \| Land Loan [Member]
Recorded investment with no allowance	100		100		97
Unpaid principal balance with no allowance	102		102		97
Average recorded investment with no allowance	100	99	99	104
Interest income recognized with no allowance	0	0	0	0
Recorded investment with allowance	51		51		0
Unpaid principal balance with allowance	54		54		0
Related allowance	5		5		0
Average recorded investment with allowance	26	0	17	0
Interest income recognized with allowance	0	0	0	0
Recorded investment	151		151		97
Unpaid principal balance	156		156		97
Average recorded investment	126	99	116	104
Interest income recognized	0	0	0	0
Real Estate Mortgage Portfolio Segment [Member] \| Construction Loans [Member]
Recorded investment with no allowance	0		0		0
Unpaid principal balance with no allowance	0		0		0
Average recorded investment with no allowance	0	0	0	0
Interest income recognized with no allowance	0	0	0	0
Recorded investment with allowance	0		0		0
Unpaid principal balance with allowance	0		0		0
Related allowance	0		0		0
Average recorded investment with allowance	0	0	0	0
Interest income recognized with allowance	0	0	0	0
Recorded investment	0		0		0
Unpaid principal balance	0		0		0
Average recorded investment	0	0	0	0
Interest income recognized	0	0	0	0
Real Estate Mortgage Portfolio Segment [Member] \| Commercial Real Estate Loan [Member]
Recorded investment with no allowance	740		740		779
Unpaid principal balance with no allowance	750		750		784
Average recorded investment with no allowance	750	883	760	706
Interest income recognized with no allowance	9	9	17	18
Recorded investment with allowance	0		0		0
Unpaid principal balance with allowance	0		0		0
Related allowance	0		0		0
Average recorded investment with allowance	0	0	0	0
Interest income recognized with allowance	0	0	0	0
Recorded investment	740		740		779
Unpaid principal balance	750		750		784
Average recorded investment	750	883	760	706
Interest income recognized	9	9	17	18
Commercial Portfolio Segment [Member]
Recorded investment with no allowance	190		190		211
Unpaid principal balance with no allowance	189		189		210
Average recorded investment with no allowance	196	265	201	260
Interest income recognized with no allowance	2	3	4	4
Recorded investment with allowance	0		0		0
Unpaid principal balance with allowance	0		0		0
Related allowance	0		0		0
Average recorded investment with allowance	0	99	0	66
Interest income recognized with allowance	0	0	0	0
Recorded investment	190		190		211
Unpaid principal balance	189		189		210
Average recorded investment	196	364	201	326
Interest income recognized	2	3	4	4
Consumer Portfolio Segment [Member] \| Home Equity and Second Mortgage [Member]
Recorded investment with no allowance	109		109		353
Unpaid principal balance with no allowance	107		107		345
Average recorded investment with no allowance	87	204	175	155
Interest income recognized with no allowance	1	4	2	5
Recorded investment with allowance	289		289		0
Unpaid principal balance with allowance	294		294		0
Related allowance	7		7		0
Average recorded investment with allowance	290	0	193	0
Interest income recognized with allowance	0	0	0	0
Recorded investment	398		398		353
Unpaid principal balance	401		401		345
Average recorded investment	377	204	368	155
Interest income recognized	1	4	2	5
Consumer Portfolio Segment [Member] \| All Other Consumer Excluding Home Equity and Second Mortgage [Member]
Recorded investment with no allowance	0		0		0
Unpaid principal balance with no allowance	0		0		0
Average recorded investment with no allowance	0	25	0	32
Interest income recognized with no allowance	0	0	0	0
Recorded investment with allowance	0		0		0
Unpaid principal balance with allowance	0		0		0
Related allowance	0		0		0
Average recorded investment with allowance	0	0	0	0
Interest income recognized with allowance	0	0	0	0
Recorded investment	0		0		0
Unpaid principal balance	0		0		$ 0
Average recorded investment	0	25	0	32
Interest income recognized	$ 0	$ 0	$ 0	$ 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=123577603&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5258-111524

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