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Note 8 - Loans and Related Allowance for Loan and Lease Losses - Troubled Debt Restructurings (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)
Residential Portfolio Segment [Member]
Number of contracts	1	1	3	2
Pre-modification outstanding recorded investment	$ 115	$ 38	$ 156	$ 123
Post-modification outstanding recorded investment	$ 115	$ 38	$ 156	$ 178
Commercial And Industrial [Member]
Number of contracts	1		3
Pre-modification outstanding recorded investment	$ 2		$ 120
Post-modification outstanding recorded investment	$ 2		$ 119
Extended Maturity [Member] | Residential Portfolio Segment [Member]
Number of contracts	1	0	3	0
Extended Maturity [Member] | Commercial And Industrial [Member]
Number of contracts	1		3
Other Restructurings [Member] | Residential Portfolio Segment [Member]
Number of contracts	0	1	0	2
Other Restructurings [Member] | Commercial And Industrial [Member]
Number of contracts	0		0

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

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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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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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