Note 12 - Fair Value of Financial Instruments (Details) - Fair Value of Financial Instruments (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Financial Assets
Securities available-for-sale	$ 1,578,897	$ 1,586,668
Trading securities		4,936
Estimate of Fair Value Measurement [Member]
Financial Assets
Cash and due from banks	161,657	153,747
Short-term investments	620,306	516,938
Securities available-for-sale	1,578,897	1,586,668
Trading securities		4,936
Loans, net	8,045,314	7,760,490
Investment in Federal Home Loan Bank stock	29,901	25,000
Warrants	28	30
Financial Liabilities
Deposits	8,233,462	7,977,639
Securities sold under agreement to repurchase	739,254	852,835
Advances from Federal Home Loan Bank	636,531	521,560
Other borrowings	16,337	16,107
Long-term debt	59,305	58,970
Fair Value, Inputs, Level 1 [Member]
Financial Assets
Cash and due from banks	161,657	153,747
Short-term investments	620,306	516,938
Securities available-for-sale	481,576	465,917
Fair Value, Inputs, Level 2 [Member]
Financial Assets
Securities available-for-sale	1,097,321	1,120,751
Trading securities		4,936
Investment in Federal Home Loan Bank stock	29,901	25,000
Financial Liabilities
Securities sold under agreement to repurchase	739,254	852,835
Advances from Federal Home Loan Bank	636,531	521,560
Long-term debt	59,305	58,970
Fair Value, Inputs, Level 3 [Member]
Financial Assets
Loans, net	8,045,314	7,760,490
Warrants	28	30
Financial Liabilities
Deposits	8,233,462	7,977,639
Other borrowings	$ 16,337	$ 16,107

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- Definition

Other borrowings fair value disclosure.

+ References

No definition available.

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- Definition

Warrants, Fair Value Disclosure

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No definition available.

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- Definition

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

+ References

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)

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- Definition

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash

-URI http://asc.fasb.org/extlink&oid=6506951

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash Equivalents

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- Definition

Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

+ References

No definition available.

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- Definition

Fair value portion of borrowing from Federal Home Loan Bank (FHLBank).

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.13(3)(a))

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- Definition

Fair value portion of investments in Federal Home Loan Bank (FHLBank) stock.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 325

-SubTopic 20

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-Paragraph 1

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- Definition

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Glossary Loan

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- Definition

The fair value amount of long-term debt 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.

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- Definition

Fair value portion of securities that an entity sells and agrees to repurchase at a specified date for a specified price.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

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- Definition

Investments which are intended to be sold in the short term (usually less than one year or the normal operating cycle, whichever is longer) including trading securities, available-for-sale securities, held-to-maturity securities, and other short-term investments not otherwise listed in the existing taxonomy.

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-Publisher FASB

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-Topic 210

-SubTopic 10

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-Paragraph 1

-Subparagraph (SX 210.5-02.2)

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-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Subparagraph g

-Article 7

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Amount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.

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