Note 6 - Investment Securities Available for Sale - Amortized Cost and Fair Values of Securities Available for Sale (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Amortized cost	$ 108,890	$ 112,557
Gross unrealized gains	2,369	2,702
Gross unrealized losses	(807)	(883)
Investment securities available for sale, at fair value	110,452	114,376
US Government Agencies Debt Securities [Member]
Amortized cost	9,732	10,158
Gross unrealized gains	167	174
Gross unrealized losses	(72)	(96)
Investment securities available for sale, at fair value	9,827	10,236
US States and Political Subdivisions Debt Securities [Member]
Investment securities available for sale, at fair value	79,697	81,223
US States and Political Subdivisions Debt Securities [Member] \| Taxable [Member]
Amortized cost	1,614	1,615
Gross unrealized gains	129	129
Gross unrealized losses	(3)	(4)
Investment securities available for sale, at fair value	1,740	1,740
US States and Political Subdivisions Debt Securities [Member] \| Tax Exempt [Member]
Amortized cost	76,804	78,327
Gross unrealized gains	1,658	1,678
Gross unrealized losses	(505)	(522)
Investment securities available for sale, at fair value	77,957	79,483
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Amortized cost	19,091	20,128
Gross unrealized gains	172	202
Gross unrealized losses	(227)	(261)
Investment securities available for sale, at fair value	19,036	20,069
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Amortized cost	1,479	1,579
Gross unrealized gains	123	130
Gross unrealized losses
Investment securities available for sale, at fair value	1,602	1,709
Debt Securities [Member]
Amortized cost	108,720	111,807
Gross unrealized gains	2,249	2,313
Gross unrealized losses	(807)	(883)
Investment securities available for sale, at fair value	110,162	113,237
Equity Securities In Financial Institutions [Member]
Amortized cost	170	750
Gross unrealized gains	120	389
Gross unrealized losses
Investment securities available for sale, at fair value	$ 290	$ 1,139

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
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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
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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