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Note 8 - Loans and Related Allowance for Loan and Lease Losses - Troubled Debt Restructurings (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($)	Mar. 31, 2019
Number of contracts		0
Residential Portfolio Segment [Member]
Number of contracts	2
Pre-modification outstanding recorded investment	$ 42
Post-modification outstanding recorded investment	$ 42
Commercial And Industrial [Member]
Number of contracts	1
Pre-modification outstanding recorded investment	$ 95
Post-modification outstanding recorded investment	$ 95
Extended Maturity [Member] | Residential Portfolio Segment [Member]
Number of contracts	2
Extended Maturity [Member] | Commercial And Industrial [Member]
Number of contracts	1
Other Restructurings [Member] | Residential Portfolio Segment [Member]
Number of contracts
Other Restructurings [Member] | Commercial And Industrial [Member]
Number of contracts

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

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- 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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Period Type:	duration

X

- Definition

Amount, before troubled debt restructuring, of financing receivable to be modified.

+ 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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X

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X

- Details

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Namespace Prefix:
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Balance Type:
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X

- Details

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