Note 3 - Investment Securities - Amortized Cost and Fair Value of Investment Securities Available-for-sale (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Securities available-for-sale, amortized cost	$ 116,881	$ 107,994
Securities available-for-sale, gross unrealized gains	432	513
Securities available-for-sale, gross unrealized losses	(1,424)	(2,299)
Securities available-for-sale, fair value	115,889	106,208
US Government Agencies Debt Securities [Member]
Securities available-for-sale, amortized cost	59,622	67,944
Securities available-for-sale, gross unrealized gains		18
Securities available-for-sale, gross unrealized losses	(1,242)	(1,806)
Securities available-for-sale, fair value	58,380	66,156
US States and Political Subdivisions Debt Securities [Member]
Securities available-for-sale, amortized cost	37,616	35,856
Securities available-for-sale, gross unrealized gains	314	366
Securities available-for-sale, gross unrealized losses	(122)	(487)
Securities available-for-sale, fair value	37,808	35,735
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Securities available-for-sale, amortized cost	17,890	2,588
Securities available-for-sale, gross unrealized gains	14	31
Securities available-for-sale, gross unrealized losses	(45)
Securities available-for-sale, fair value	17,859	2,619
Equity Securities - Mutual Funds [Member]
Securities available-for-sale, amortized cost	500	500
Securities available-for-sale, gross unrealized gains	10	7
Securities available-for-sale, gross unrealized losses
Securities available-for-sale, fair value	510	507
Equity Securities [Member]
Securities available-for-sale, amortized cost	1,253	1,106
Securities available-for-sale, gross unrealized gains	94	91
Securities available-for-sale, gross unrealized losses	(15)	(6)
Securities available-for-sale, fair value	$ 1,332	$ 1,191

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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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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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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