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Note 3 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Impaired Loans, Average Investment and Interest Income (Details) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Mar. 31, 2021

Mar. 31, 2020

Dec. 31, 2020

Average recorded investment in impaired loans(1)

^[1]

$ 4,956

$ 5,677

$ 5,093

Interest income recognized on impaired loans, after designation as impaired

46

26

54

Investor Owned Residential Real Estate [Member] | Consumer Real Estate Portfolio Segment [Member]

Average recorded investment in impaired loans(1)

^[1],[2]

194

487

196

Interest income recognized on impaired loans, after designation as impaired

^[2]

3

4

13

Equity Lines [Member] | Consumer Real Estate Portfolio Segment [Member]

Average recorded investment in impaired loans(1)

^[1],[2]

100

Interest income recognized on impaired loans, after designation as impaired

^[2]

2

Closed End First Liens [Member] | Consumer Real Estate Portfolio Segment [Member]

Average recorded investment in impaired loans(1)

^[1],[2]

22

Interest income recognized on impaired loans, after designation as impaired

^[2]

0

Commercial Real Estate, Owner Occupied [Member] | Commercial Real Estate Portfolio Segment [Member]

Average recorded investment in impaired loans(1)

^[1],[2]

3,269

3,309

3,217

Interest income recognized on impaired loans, after designation as impaired

^[2]

38

6

19

Commercial Real Estate Other [Member] | Commercial Real Estate Portfolio Segment [Member]

Average recorded investment in impaired loans(1)

^[1],[2]

654

838

790

Interest income recognized on impaired loans, after designation as impaired

^[2]

8

0

Commercial and Industrial [Member] | Commercial Non Real Estate Segment [Member]

Average recorded investment in impaired loans(1)

^[1],[2]

838

917

887

Interest income recognized on impaired loans, after designation as impaired

^[2]

5

6

22

Automobile Loan [Member] | Consumer Non Real Estate Portfolio Segment [Member]

Average recorded investment in impaired loans(1)

^[1],[2]

$ 1

$ 4

3

Interest income recognized on impaired loans, after designation as impaired

^[2]

$ 0

[1]	Recorded investment is net of charge-offs and interest paid while a loan is in nonaccrual status.
[2]	Only classes with impaired loans are shown.

X

- Definition

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

+ Details

Name:	us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

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)(2)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

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Namespace Prefix:
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Balance Type:
Period Type:

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- Details

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Namespace Prefix:
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- Details

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Namespace Prefix:
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- Details

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Namespace Prefix:
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Period Type:

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- Details

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Namespace Prefix:
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- Details

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Namespace Prefix:
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- Details

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Namespace Prefix:
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Balance Type:
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- Details

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Namespace Prefix:
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Balance Type:
Period Type:

X

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

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Namespace Prefix:
Data Type:	na
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