Note 9 - Allowance for Loan Losses and Credit Quality Information - Financial Effects of Troubled Debt Restructurings (Details) $ in Thousands	3 Months Ended
Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)
Number of Contracts	8	5
Pre- modification Outstanding Recorded Investment	$ 1,570	$ 327
Post- modification Outstanding Recorded Investment	$ 1,574	$ 559
Residential Portfolio Segment [Member]
Number of Contracts	1	3
Pre- modification Outstanding Recorded Investment	$ 55	$ 282
Post- modification Outstanding Recorded Investment	$ 58	$ 514
Commercial Real Estate Portfolio Segment [Member] \| Real Estate Loan [Member]
Number of Contracts	1	0
Pre- modification Outstanding Recorded Investment	$ 54	$ 0
Post- modification Outstanding Recorded Investment	$ 54	$ 0
Commercial Real Estate Portfolio Segment [Member] \| Commercial Real Estate Other [Member]
Number of Contracts	1	0
Pre- modification Outstanding Recorded Investment	$ 1,274	$ 0
Post- modification Outstanding Recorded Investment	$ 1,274	$ 0
Consumer Portfolio Segment [Member]
Number of Contracts	4	2
Pre- modification Outstanding Recorded Investment	$ 117	$ 45
Post- modification Outstanding Recorded Investment	$ 118	$ 45
Commercial Portfolio Segment [Member]
Number of Contracts	1	0
Pre- modification Outstanding Recorded Investment	$ 70	$ 0
Post- modification Outstanding Recorded Investment	$ 70	$ 0

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

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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