Note 3 - Securities - Held-to-maturity Securities (Details) - Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] - USD ($)	Sep. 30, 2017	Dec. 31, 2016
Debt Securities:
Held-to-maturity securities, amortized cost	$ 18,424	$ 27,528
Held-to-maturity securities, gross unrealized gains	215	625
Held-to-maturity securities, gross unrealized losses	(57)	0
Held-to-maturity securities, approximate fair value	$ 18,582	$ 28,153

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Amount of accumulated unrealized gain on investments in debt securities classified as held-to-maturity.

+ References

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- Definition

Amount of accumulated unrealized loss on investments in debt securities classified as held-to-maturity.

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- Definition

Amount before other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

+ References

No definition available.

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- Definition

Fair value of investments in debt securities classified as held-to-maturity.

+ References

Reference 1: 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 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (f)
-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 50
-Paragraph 5
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563

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