Note 4 - Loans and Allowance for Loan Losses - Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Valuation allowance	$ 1,326		$ 1,326		$ 602
Loans recorded balance	8,863		8,863		8,699
Loans unpaid principal	10,669		10,669		10,384
Loans interest income recognized				$ 1
Loans average investment in impaired loans	8,660	11,678	8,835	12,524
Residential Portfolio Segment [Member] \| Real Estate Residential, One To Four Family Units [Member]
Loans without a specific valuation allowance, recorded balance	1,815		1,815		2,006
Loans without a specific valuation allowance, unpaid principal	1,815		1,815		2,006
Loans with a specific valuation allowance, recorded balance	459		459		54
Loans with a specific valuation allowance, unpaid principal	459		459		54
Valuation allowance	56		56		14
Loans recorded balance	2,274		2,274		2,060
Loans unpaid principal	2,274		2,274		2,060
Loans without a specific valuation allowance, average investment in impaired loans	1,946	2,153	1,886	2,200
Loans interest income recognized
Loans with a specific valuation allowance, average investment in impaired loans	183	28	90	23
Loans average investment in impaired loans	2,129	2,181	1,976	2,223
Residential Portfolio Segment [Member] \| Real Estate Residential, Multi Family Units [Member]
Loans without a specific valuation allowance, recorded balance
Loans without a specific valuation allowance, unpaid principal
Valuation allowance
Loans recorded balance
Loans unpaid principal
Loans without a specific valuation allowance, average investment in impaired loans
Loans interest income recognized
Loans with a specific valuation allowance, average investment in impaired loans
Loans average investment in impaired loans
Residential Portfolio Segment [Member] \| Construction Loans [Member]
Loans without a specific valuation allowance, average investment in impaired loans	2,937	5,597	2,964	5,661
Loans interest income recognized
Loans with a specific valuation allowance, average investment in impaired loans	2,373	2,051	2,395	2,222
Loans average investment in impaired loans	5,310	7,648	5,359	7,883
Real Estate, Construction [Member]
Loans without a specific valuation allowance, recorded balance	2,937		2,937		3,017
Loans without a specific valuation allowance, unpaid principal	2,937		2,937		3,017
Loans with a specific valuation allowance, recorded balance	2,373		2,373		2,430
Loans with a specific valuation allowance, unpaid principal	3,606		3,606		3,663
Valuation allowance	830		830		302
Loans recorded balance	5,310		5,310		5,447
Loans unpaid principal	6,543		6,543		6,680
Commercial Real Estate Portfolio Segment [Member]
Loans without a specific valuation allowance, recorded balance	161		161		161
Loans without a specific valuation allowance, unpaid principal	161		161		161
Loans with a specific valuation allowance, recorded balance
Loans with a specific valuation allowance, unpaid principal	72		72
Valuation allowance
Loans recorded balance	161		161		161
Loans unpaid principal	233		233		161
Loans without a specific valuation allowance, average investment in impaired loans	161	244	360	657
Loans interest income recognized
Loans with a specific valuation allowance, average investment in impaired loans		278		93
Loans average investment in impaired loans	161	522	360	750
Commercial Portfolio Segment [Member]
Loans without a specific valuation allowance, recorded balance	500		500		622
Loans without a specific valuation allowance, unpaid principal	500		500		622
Loans with a specific valuation allowance, recorded balance	431		431		303
Loans with a specific valuation allowance, unpaid principal	932		932		755
Valuation allowance	310		310		241
Loans recorded balance	931		931		925
Loans unpaid principal	1,432		1,432		1,377
Loans without a specific valuation allowance, average investment in impaired loans	504	657	557	960
Loans interest income recognized
Loans with a specific valuation allowance, average investment in impaired loans	431	375	481	489
Loans average investment in impaired loans	935	1,032	1,038	1,449
Consumer and Other Loans [Member]
Loans without a specific valuation allowance, recorded balance	4		4		3
Loans without a specific valuation allowance, unpaid principal	4		4		3
Loans with a specific valuation allowance, recorded balance	183		183		103
Loans with a specific valuation allowance, unpaid principal	183		183		103
Valuation allowance	130		130		45
Loans recorded balance	187		187		106
Loans unpaid principal	187		187		$ 106
Consumer Portfolio Segment [Member]
Loans without a specific valuation allowance, average investment in impaired loans	2	185	8	114
Loans interest income recognized				1
Loans with a specific valuation allowance, average investment in impaired loans	123	110	94	105
Loans average investment in impaired loans	$ 125	$ 295	$ 102	$ 219

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=84173941&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=84173941&loc=d3e5258-111524

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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 14A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953550-111524

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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=84173941&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=84173941&loc=d3e5212-111524

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