Note 4 - Investment Securities Available for Sale (Details) - Investment Securities (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Investment securities available for sale, amortized cost	$ 173,282	$ 71,295
Investment securities available for sale, gross unrealized gains	1,363	210
Investment securities available for sale, gross unrealized losses	(427)	(677)
Investment securities available for sale	174,218us-gaap_AvailableForSaleSecurities	70,828us-gaap_AvailableForSaleSecurities
US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities available for sale, amortized cost	77,550
Investment securities available for sale, gross unrealized gains	7
Investment securities available for sale, gross unrealized losses	(225)
Investment securities available for sale	77,332
US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities available for sale, amortized cost	58,812	42,203
Investment securities available for sale, gross unrealized gains	456	199
Investment securities available for sale, gross unrealized losses	(188)	(478)
Investment securities available for sale	59,080	41,924
Collateralized Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities available for sale, amortized cost	36,920	29,092
Investment securities available for sale, gross unrealized gains	900	11
Investment securities available for sale, gross unrealized losses	(14)	(199)
Investment securities available for sale	$ 37,806	$ 28,904

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

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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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