Note 4 - Investment Securities Available for Sale (Details) - Investment Securities (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities, amortized cost	$ 175,004	$ 173,282
Available for sale securities, gross unrealized gains	1,805	1,363
Available for sale securities, gross unrealized losses	(210)	(427)
Available for sale securities, fair value	176,599us-gaap_AvailableForSaleSecurities	174,218us-gaap_AvailableForSaleSecurities
US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities, amortized cost	76,505	77,550
Available for sale securities, gross unrealized gains	39	7
Available for sale securities, gross unrealized losses	(33)	(225)
Available for sale securities, fair value	76,511	77,332
US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities, amortized cost	61,850	58,812
Available for sale securities, gross unrealized gains	650	456
Available for sale securities, gross unrealized losses	(176)	(188)
Available for sale securities, fair value	62,324	59,080
Collateralized Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities, amortized cost	36,649	36,920
Available for sale securities, gross unrealized gains	1,116	900
Available for sale securities, gross unrealized losses	(1)	(14)
Available for sale securities, fair value	$ 37,764	$ 37,806

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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