Note 12 - Fair Value of Financial Instruments - Fair Value Hierarchy of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Fair Value, Inputs, Level 1 [Member]
Cash and due from banks	$ 203,877	$ 180,130
Short-term investments	791,757	536,880
Available-for-sale Securities	395,935	290,121
Loans held-for-sale
Loans, net
Investment in Federal Home Loan Bank stock
Warrants
Deposits
Securities sold under agreements to repurchase
Advances from Federal Home Loan Bank
Other borrowings .
Long-term debt
Fair Value, Inputs, Level 2 [Member]
Cash and due from banks
Short-term investments
Available-for-sale Securities	902,534	1,296,231
Loans held-for-sale
Loans, net
Investment in Federal Home Loan Bank stock	18,900	17,250
Warrants
Deposits
Securities sold under agreements to repurchase	355,422	413,417
Advances from Federal Home Loan Bank	700,130
Other borrowings .
Long-term debt	62,628	58,420
Fair Value, Inputs, Level 3 [Member]
Cash and due from banks
Short-term investments
Available-for-sale Securities
Loans held-for-sale	4,750	6,676
Loans, net	10,825,059	9,938,810
Investment in Federal Home Loan Bank stock
Warrants	75	62
Deposits	10,946,853	10,509,879
Securities sold under agreements to repurchase
Advances from Federal Home Loan Bank		274,488
Other borrowings .	15,903	16,684
Long-term debt
Cash and due from banks	203,877	180,130
Short-term investments	791,757	536,880
Available-for-sale Securities	1,298,469	1,586,352
Loans held-for-sale	4,750	6,676
Loans, net	10,825,059	9,938,810
Investment in Federal Home Loan Bank stock	18,900	17,250
Warrants	75	62
Deposits	10,946,853	10,509,879
Securities sold under agreements to repurchase	355,422	413,417
Advances from Federal Home Loan Bank	700,130	274,488
Other borrowings .	15,903	16,684
Long-term debt	$ 62,628	$ 58,420

Other borrowings fair value disclosure.

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- Definition

Warrants, Fair Value Disclosure

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No definition available.

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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
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-Paragraph 1
-Subparagraph (b)
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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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-Name Accounting Standards Codification
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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.

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

+ References

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

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Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

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No definition available.

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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.

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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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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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Amount of investments including trading securities, available-for-sale securities, held-to-maturity securities, and short-term investments classified as other and current.

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