Note 4 - Securities - Securities Available-for-sale (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Securities available-for-sale, Gross Unrealized Gains	$ 1,495	$ 808
Securities available-for-sale, Gross Unrealized Losses	2,860	6,328
Securities available-for-sale, Fair Values	308,435	304,282
Securities available-for-sale, Amortized Costs	309,800	309,802
US Government Agencies Debt Securities [Member]
Securities available-for-sale, Gross Unrealized Gains	1,006	492
Securities available-for-sale, Gross Unrealized Losses	2,832	6,165
Securities available-for-sale, Fair Values	292,776	285,598
Securities available-for-sale, Amortized Costs	294,602	291,271
US States and Political Subdivisions Debt Securities [Member]
Securities available-for-sale, Gross Unrealized Gains	159	211
Securities available-for-sale, Gross Unrealized Losses	0	0
Securities available-for-sale, Fair Values	8,442	11,693
Securities available-for-sale, Amortized Costs	8,283	11,482
Collateralized Mortgage Backed Securities [Member]
Securities available-for-sale, Gross Unrealized Gains	72	85
Securities available-for-sale, Gross Unrealized Losses	0	0
Securities available-for-sale, Fair Values	783	930
Securities available-for-sale, Amortized Costs	711	845
Corporate Debt Securities [Member]
Securities available-for-sale, Gross Unrealized Gains	255	20
Securities available-for-sale, Gross Unrealized Losses	28	137
Securities available-for-sale, Fair Values	6,242	5,898
Securities available-for-sale, Amortized Costs	6,015	6,015
Other Securities [Member]
Securities available-for-sale, Gross Unrealized Gains	3	0
Securities available-for-sale, Gross Unrealized Losses	0	26
Securities available-for-sale, Fair Values	192	163
Securities available-for-sale, Amortized Costs	$ 189	$ 189

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=75030427&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
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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=82896770&loc=d3e26610-111562

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Paragraph 2
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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.

+ References

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