Note 7 - Investment Securities (Detail) - The Amortized Costs And Estimated Fair Value Of The Securities Portfolio (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Available For Sale
Available for Sale Securities - Amortized Cost	$ 556,258	$ 558,630
Available for Sale Securities - Gross Unrealized Losses	1,500
Available for Sale Securities - Estimated Fair Value	569,302	573,108
Held To Maturity
Held to Maturity Securities - Amortized Cost	820	820
Held to Maturity Securities - Estimated Fair Value	948	956
US Government-sponsored Enterprises Debt Securities [Member]
Available For Sale
Available for Sale Securities - Amortized Cost	82,912	75,945
Available for Sale Securities - Gross Unrealized Gains	165	216
Available for Sale Securities - Gross Unrealized Losses	137	66
Available for Sale Securities - Estimated Fair Value	82,940	76,095
US States and Political Subdivisions Debt Securities [Member]
Available For Sale
Available for Sale Securities - Amortized Cost	122,307	113,986
Available for Sale Securities - Gross Unrealized Gains	4,462	4,943
Available for Sale Securities - Gross Unrealized Losses	279	174
Available for Sale Securities - Estimated Fair Value	126,490	118,755
Held To Maturity
Held to Maturity Securities - Amortized Cost	820	820
Held to Maturity Securities - Gross Unrealized Gains	128	136
Held to Maturity Securities - Estimated Fair Value	948	956
Residential Mortgage Backed Securities [Member]
Available For Sale
Available for Sale Securities - Amortized Cost	342,424	360,099
Available for Sale Securities - Gross Unrealized Gains	9,810	10,596
Available for Sale Securities - Gross Unrealized Losses	416	256
Available for Sale Securities - Estimated Fair Value	351,818	370,439
Corporate Debt Securities [Member]
Available For Sale
Available for Sale Securities - Amortized Cost	7,133	6,638
Available for Sale Securities - Gross Unrealized Gains	50	44
Available for Sale Securities - Gross Unrealized Losses	647	856
Available for Sale Securities - Estimated Fair Value	6,536	5,826
Mutual Funds And Equity Securities [Member]
Available For Sale
Available for Sale Securities - Amortized Cost	1,482	1,962
Available for Sale Securities - Gross Unrealized Gains	38	33
Available for Sale Securities - Gross Unrealized Losses	2	2
Available for Sale Securities - Estimated Fair Value	1,518	1,993
Total [Member]
Available For Sale
Available for Sale Securities - Amortized Cost	556,258	558,630
Available for Sale Securities - Gross Unrealized Gains	14,525	15,832
Available for Sale Securities - Gross Unrealized Losses	1,481	1,354
Available for Sale Securities - Estimated Fair Value	$ 569,302	$ 573,108

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.

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This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

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- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

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- Definition

For an unclassified balance sheet, this item represents investments in debt securities which are categorized as held-to-maturity. The held-to-maturity category is for those securities that the entity has the positive intent and ability to hold until maturity.

+ References

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

-Publisher FASB

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-Name Accounting Research Bulletin (ARB)

-Number 43

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-Publisher FASB

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-Number 115

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 8

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 9: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 11

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 10: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

-Number 43

-Section A

-Paragraph 4

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 11: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 7

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 12: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.6)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

- Definition

This item represents the aggregate fair value of investments in debt securities as of the balance sheet date and which are categorized as held-to-maturity.

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- Definition

As of the balance sheet date, the excess of fair value over carrying value (amortized cost) of a debt security categorized as held-to-maturity, exclusive of dividend or interest income recognized but not yet received and exclusive of any write-downs for other-than-temporary impairment. Such item represents the gross unrecognized holding gain.

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