Note 7 - Loans and Related Allowance for Loan Losses - Troubled Debt Restructurings (Details) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)
Commercial And Industrial [Member]
Pre-modification outstanding recorded investment	$ 904	$ 3	$ 954	$ 169
Post-modification outstanding recorded investment	$ 905	$ 3	$ 955	$ 169
Number of contracts	1	1	2	2
Real Estate Mortgage Portfolio Segment [Member] \| Residential Loan [Member]
Pre-modification outstanding recorded investment	$ 7	$ 58	$ 10	$ 58
Post-modification outstanding recorded investment	$ 7	$ 58	$ 10	$ 58
Number of contracts	1	1	2	1
Commercial Real Estate Portfolio Segment [Member]
Pre-modification outstanding recorded investment		$ 311		$ 311
Post-modification outstanding recorded investment		$ 311		$ 311
Number of contracts		1		1
Extended Maturity [Member] \| Commercial And Industrial [Member]
Number of contracts		1	1	2
Extended Maturity [Member] \| Real Estate Mortgage Portfolio Segment [Member] \| Residential Loan [Member]
Number of contracts	1	1	2	1
Extended Maturity [Member] \| Commercial Real Estate Portfolio Segment [Member]
Number of contracts		1		1
Other Restructurings [Member] \| Commercial And Industrial [Member]
Number of contracts	1		1
Other Restructurings [Member] \| Real Estate Mortgage Portfolio Segment [Member] \| Residential Loan [Member]
Number of contracts
Other Restructurings [Member] \| Commercial Real Estate Portfolio Segment [Member]
Number of contracts

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-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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