Note 6 - Investment Securities Available for Sale - Amortized Cost and Fair Value of Investment Securities Available for Sale (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Amortized cost	$ 7,931	$ 9,612
Gross unrealized gains	19	1
Gross unrealized losses	(38)	(58)
Investment securities available for sale	7,912	9,555
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Amortized cost	7,571	9,252
Gross unrealized gains	19	1
Gross unrealized losses	(35)	(52)
Investment securities available for sale	7,555	9,201
US Government Agencies Debt Securities [Member]
Amortized cost	360	360
Gross unrealized gains
Gross unrealized losses	(3)	(6)
Investment securities available for sale	357	354
Government National Mortgage Association (GNMA) Insured Loans [Member] \| Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Amortized cost	5,624	6,608
Gross unrealized gains	19	1
Gross unrealized losses		(19)
Investment securities available for sale	5,643	6,590
Federal Home Loan Mortgage Corporation (FHLMC) Insured Loans [Member] \| Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Amortized cost	1,377	1,892
Gross unrealized gains
Gross unrealized losses	(35)	(21)
Investment securities available for sale	1,342	1,871
Federal National Mortgage Association (FNMA) Insured Loans [Member] \| Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Amortized cost	570	752
Gross unrealized gains
Gross unrealized losses		(12)
Investment securities available for sale	$ 570	$ 740

This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.2)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=75030427&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82896770&loc=d3e26610-111562

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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