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Note 5 - Loans and Related Allowance for Loan and Lease Losses - Troubled Debt Restructurings (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Number of contracts
Pre-modification outstanding recorded investment	$ 424	$ 383
Post-modification outstanding recorded investment	$ 424	$ 383
Commercial And Industrial [Member]
Number of contracts	1	4
Pre-modification outstanding recorded investment	$ 44	$ 127
Post-modification outstanding recorded investment	$ 44	$ 127
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Number of contracts	5	5
Pre-modification outstanding recorded investment	$ 286	$ 256
Post-modification outstanding recorded investment	$ 286	$ 256
Commercial Real Estate Portfolio Segment [Member]
Number of contracts	1
Pre-modification outstanding recorded investment	$ 94
Post-modification outstanding recorded investment	$ 94
Extended Maturity [Member]
Number of contracts
Extended Maturity [Member] | Commercial And Industrial [Member]
Number of contracts	1	4
Extended Maturity [Member] | Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Number of contracts	3	5
Extended Maturity [Member] | Commercial Real Estate Portfolio Segment [Member]
Number of contracts	1
Other Restructurings [Member]
Number of contracts
Other Restructurings [Member] | Commercial And Industrial [Member]
Number of contracts
Other Restructurings [Member] | Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Number of contracts	2
Other Restructurings [Member] | Commercial Real Estate Portfolio Segment [Member]
Number of contracts

X

- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953676-111524

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- Definition

Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953676-111524

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- Definition

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+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953676-111524

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