Note 5 - Securities - Securities Available-for-sale (Details) - USD ($)	Jun. 30, 2016	Dec. 31, 2015
US Government Agencies Debt Securities [Member]
Securities available-for-sale, Amortized Costs	$ 280,386,000	$ 216,897,000
Securities available-for-sale, Gross Unrealized Gains	1,576,000	519,000
Securities available-for-sale, Gross Unrealized Losses	239,000	4,952,000
Securities available for sale	281,723,000	212,464,000
US States and Political Subdivisions Debt Securities [Member]
Securities available-for-sale, Amortized Costs	13,573,000	15,934,000
Securities available-for-sale, Gross Unrealized Gains	420,000	541,000
Securities available-for-sale, Gross Unrealized Losses	0	0
Securities available for sale	13,993,000	16,475,000
Collateralized Mortgage Backed Securities [Member]
Securities available-for-sale, Amortized Costs	1,031,000	1,199,000
Securities available-for-sale, Gross Unrealized Gains	113,000	120,000
Securities available-for-sale, Gross Unrealized Losses	0	0
Securities available for sale	1,144,000	1,319,000
Corporate Debt Securities [Member]
Securities available-for-sale, Amortized Costs	6,016,000	6,015,000
Securities available-for-sale, Gross Unrealized Gains	260,000	22,000
Securities available-for-sale, Gross Unrealized Losses	35,000	291,000
Securities available for sale	6,241,000	5,746,000
Other Securities [Member]
Securities available-for-sale, Amortized Costs	189,000	189,000
Securities available-for-sale, Gross Unrealized Gains	0
Securities available-for-sale, Gross Unrealized Losses	48,000	62,000
Securities available for sale	141,000	127,000
Securities available-for-sale, Amortized Costs	301,195,000	240,234,000
Securities available-for-sale, Gross Unrealized Gains	2,369,000	1,202,000
Securities available-for-sale, Gross Unrealized Losses	322,000	5,305,000
Securities available for sale	$ 303,242,000	$ 236,131,000

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
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=66010992&loc=d3e26610-111562

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- Definition

Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563

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- Definition

Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563

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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.2)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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