Note 3 - Impaired Loans (Additional Information) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Commercial Portfolio Segment [Member]
With no allowance recorded, average recorded investment	$ 116			$ 1
With no allowance recorded, interest income recognized
With allowance recorded, average recorded investment	2,977		$ 1,914
With allowance recorded, interest income recognized
Average recorded investment	3,093		2,062	1
Interest income recognized
Commercial Real Estate Portfolio Segment [Member]
With no allowance recorded, average recorded investment	7,524	8,025	7,597	8,160
With no allowance recorded, interest income recognized	79	94	159	188
With allowance recorded, average recorded investment
With allowance recorded, interest income recognized
Average recorded investment	7,524	8,025	7,597	8,160
Interest income recognized	79	94	159	188
Residential Portfolio Segment [Member]
With no allowance recorded, average recorded investment	4,525	3,392	4,535	3,459
With no allowance recorded, interest income recognized	31	32	62	63
With allowance recorded, average recorded investment
With allowance recorded, interest income recognized
Average recorded investment	4,525	3,392	4,535	3,459
Interest income recognized	31	32	62	63
Consumer Portfolio Segment [Member]
With no allowance recorded, average recorded investment	545	551	546	552
With no allowance recorded, interest income recognized	5	5	9	9
With allowance recorded, average recorded investment	2		2	1
With allowance recorded, interest income recognized
Average recorded investment	547	551	548	553
Interest income recognized	5	5	9	9
With no allowance recorded, average recorded investment	12,710	11,968	12,826	12,172
With no allowance recorded, interest income recognized	115	131	230	260
With allowance recorded, average recorded investment	2,979		1,916	1
With allowance recorded, interest income recognized
Average recorded investment	15,688	11,968	14,742	12,173
Interest income recognized	$ 115	$ 131	$ 230	$ 260

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5212-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5258-111524

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- Definition

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5258-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5212-111524

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