Note 5 - Loans and Allowance for Loan Losses - Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Valuation allowance	$ 1,484		$ 1,612
Loans recorded balance	19,097		20,552
Loans unpaid principal	20,330		21,870
Loans interest income recognized	5	$ 5
Loans average investment in impaired loans	19,266	10,463
Residential Portfolio Segment [Member] \| Real Estate Residential, One To Four Family Units [Member]
Loans without a specific valuation allowance, recorded balance	1,382		2
Loans without a specific valuation allowance, unpaid principal	1,382		2
Loans with a specific valuation allowance, recorded balance	2,740		4,518
Loans with a specific valuation allowance, unpaid principal	2,740		4,518
Valuation allowance	630		573
Loans recorded balance	4,122		4,520
Loans unpaid principal	4,122		4,520
Loans without a specific valuation allowance, average investment in impaired loans	1,079	2,688
Loans interest income recognized	1
Loans with a specific valuation allowance, average investment in impaired loans	3,011	1,607
Loans average investment in impaired loans	4,090	4,295
Residential Portfolio Segment [Member] \| Real Estate Residential, Multi Family Units [Member]
Loans without a specific valuation allowance, recorded balance	5,930		5,952
Loans without a specific valuation allowance, unpaid principal	5,930		5,952
Loans with a specific valuation allowance, recorded balance
Loans with a specific valuation allowance, unpaid principal
Valuation allowance
Loans recorded balance	5,930		5,952
Loans unpaid principal	5,930		5,952
Loans without a specific valuation allowance, average investment in impaired loans	5,938	765
Loans interest income recognized		5
Loans with a specific valuation allowance, average investment in impaired loans
Loans average investment in impaired loans	5,938	765
Residential Portfolio Segment [Member] \| Construction Loans [Member]
Loans without a specific valuation allowance, average investment in impaired loans		2,775
Loans interest income recognized
Loans with a specific valuation allowance, average investment in impaired loans	3,805	1,612
Loans average investment in impaired loans	3,805	4,387
Real Estate, Construction [Member]
Loans without a specific valuation allowance, recorded balance
Loans without a specific valuation allowance, unpaid principal
Loans with a specific valuation allowance, recorded balance	4,004		4,088
Loans with a specific valuation allowance, unpaid principal	5,237		5,321
Valuation allowance	552		552
Loans recorded balance	4,004		4,088
Loans unpaid principal	5,237		5,321
Commercial Real Estate Portfolio Segment [Member]
Loans without a specific valuation allowance, recorded balance	3,297		3,138
Loans without a specific valuation allowance, unpaid principal	3,297		3,138
Loans with a specific valuation allowance, recorded balance	708		1,232
Loans with a specific valuation allowance, unpaid principal	708		1,317
Valuation allowance	107		106
Loans recorded balance	4,005		4,370
Loans unpaid principal	4,005		4,455
Loans without a specific valuation allowance, average investment in impaired loans	3,472	161
Loans interest income recognized	4
Loans with a specific valuation allowance, average investment in impaired loans	726
Loans average investment in impaired loans	4,198	161
Commercial Portfolio Segment [Member]
Loans without a specific valuation allowance, recorded balance	216		216
Loans without a specific valuation allowance, unpaid principal	216		216
Loans with a specific valuation allowance, recorded balance	515		1,062
Loans with a specific valuation allowance, unpaid principal	515		1,062
Valuation allowance	180		363
Loans recorded balance	731		1,278
Loans unpaid principal	731		1,278
Loans without a specific valuation allowance, average investment in impaired loans	232	349
Loans interest income recognized
Loans with a specific valuation allowance, average investment in impaired loans	667	323
Loans average investment in impaired loans	899	672
Consumer and Other Loans [Member]
Loans without a specific valuation allowance, recorded balance	212		225
Loans without a specific valuation allowance, unpaid principal	212		225
Loans with a specific valuation allowance, recorded balance	93		119
Loans with a specific valuation allowance, unpaid principal	93		119
Valuation allowance	15		18
Loans recorded balance	305		344
Loans unpaid principal	305		$ 344
Consumer Portfolio Segment [Member]
Loans without a specific valuation allowance, average investment in impaired loans	216	2
Loans interest income recognized
Loans with a specific valuation allowance, average investment in impaired loans	120	181
Loans average investment in impaired loans	$ 336	$ 183

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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5258-111524

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