Note 17 - Fair Value of Financial Instruments (Detail) - Fair Value of Financial Instruments (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Financial Assets
Securities available-for-sale	$ 1,291,480
Estimate of Fair Value, Fair Value Disclosure [Member]
Financial Assets
Cash and due from banks	144,909	117,888
Short-term investments	411,983	294,956
Securities held-to-maturity	823,906	1,203,977
Securities available-for-sale	1,291,480	1,294,478
Trading securities	4,703	4,542
Loans held-for-sale		760
Loans, net	7,169,732	6,825,571
Investment in Federal Home Loan Bank stock	41,272	52,989
Warrants	104	218
Financial Liabilities
Deposits	7,389,015	7,240,857
Securities sold under agreement to repurchase	1,361,585	1,547,900
Advances from Federal Home Loan Bank	146,789	227,825
Other borrowings	14,573	19,801
Long-term debt	98,392	98,676
Fair Value, Inputs, Level 1 [Member]
Financial Assets
Cash and due from banks	144,909	117,888
Short-term investments	411,983	294,956
Securities available-for-sale	526,165	54,958
Trading securities		2
Fair Value, Inputs, Level 2 [Member]
Financial Assets
Securities held-to-maturity	823,906	1,203,977
Securities available-for-sale	765,315	1,239,520
Trading securities	4,703	4,540
Loans held-for-sale		760
Investment in Federal Home Loan Bank stock	41,272	52,989
Financial Liabilities
Securities sold under agreement to repurchase	1,361,585	1,547,900
Advances from Federal Home Loan Bank	146,789	227,825
Long-term debt	98,392	98,676
Fair Value, Inputs, Level 3 [Member]
Financial Assets
Loans, net	7,169,732	6,825,571
Warrants	104	218
Financial Liabilities
Deposits	7,389,015	7,240,857
Other borrowings	$ 14,573	$ 19,801

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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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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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