Note 4 - Loans Receivable and Allowance for Loan Losses - Impaired Loans (Additional Information) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
With no allowance recorded, average recorded investment	$ 12,056	$ 12,063	$ 13,786
With no allowance recorded, interest income recognized	340	517	494
With allowance recorded, average recorded investment	2,205	3	7
With allowance recorded, interest income recognized
Impaired Loans, Average recorded investment	14,261	12,066	13,793
Impaired Loans, interest income recognized	340	517	494
Commercial Real Estate Portfolio Segment [Member]
With no allowance recorded, average recorded investment	6,929	8,001	8,262
With no allowance recorded, interest income recognized	312	373	342
With allowance recorded, average recorded investment	65
With allowance recorded, interest income recognized
Impaired Loans, Average recorded investment	6,994	8,001	8,262
Impaired Loans, interest income recognized	312	373	342
Residential Portfolio Segment [Member]
With no allowance recorded, average recorded investment	4,318	3,512	4,734
With no allowance recorded, interest income recognized	9	126	129
Impaired Loans, Average recorded investment	4,318	3,512	4,734
Impaired Loans, interest income recognized	9	126	129
Commercial Portfolio Segment [Member]
With no allowance recorded, average recorded investment	265		215
With no allowance recorded, interest income recognized
With allowance recorded, average recorded investment	2,138
With allowance recorded, interest income recognized
Impaired Loans, Average recorded investment	2,403		215
Impaired Loans, interest income recognized
Consumer Portfolio Segment [Member]
With no allowance recorded, average recorded investment	544	550	575
With no allowance recorded, interest income recognized	19	18	23
With allowance recorded, average recorded investment	2	3	7
With allowance recorded, interest income recognized
Impaired Loans, Average recorded investment	546	553	582
Impaired Loans, interest income recognized	$ 19	$ 18	$ 23

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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- Definition

Amount of average investment of impaired financing receivables for which there is no related allowance for credit losses.

+ 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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