Note 3 - Securities - Securities Held-to-maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Securities held to maturity, amortized cost	$ 15,590	$ 15,816
Securities held to maturity, gross unrecognized gains	546	502
Securities held to maturity, gross unrecognized losses	(12)	(84)
Securities held to maturity	16,124	16,234
US States and Political Subdivisions Debt Securities [Member]
Securities held to maturity, amortized cost	15,587	15,813
Securities held to maturity, gross unrecognized gains	546	502
Securities held to maturity, gross unrecognized losses	(12)	(84)
Securities held to maturity	16,121	16,231
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Securities held to maturity, amortized cost	3	3
Securities held to maturity, gross unrecognized gains
Securities held to maturity, gross unrecognized losses
Securities held to maturity	$ 3	$ 3

Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27232-111563

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- Definition

Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27232-111563

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- Definition

Amount, before other-than-temporary impairment (OTTI) accretion, of investment in debt securities measured at amortized cost (held-to-maturity).

+ References

No definition available.

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- Definition

Fair value of investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27232-111563

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