Note 10 - Borrowed Funds (Details Textual) $ in Thousands	Sep. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)
Securities Sold under Agreements to Repurchase	$ 100,000	$ 350,000
Weighted Average Rate Of Securities Sold Under Agreements	2.86%	4.06%
Advances from Federal Home Loan Banks	$ 595,000	$ 350,000
Mature in October 2017 [Member]
Advances from Federal Home Loan Banks	490,000
Mature in 2018 [Member]
Advances from Federal Home Loan Banks	55,000
Mature in December 2019 [Member]
Advances from Federal Home Loan Banks	50,000
Over-night Borrowings [Member]
Advances from Federal Home Loan Banks	$ 450,000	$ 275,000
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Interest Rate	1.16%	0.55%
Non Overnight Borrowings [Member]
Advances from Federal Home Loan Banks	$ 145,000
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Interest Rate	1.35%
Securities Sold under Agreements to Repurchase [Member]
Investment Securities Pledged As Collateral	$ 108,000	$ 372,000
Non Callable Fixed Rate Securities [Member]
Number Of Securities Sold Under Agreements To Repurchase	2
Non Callable Fixed Rate Securities [Member] \| Mature in August 2016 [Member]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	$ 50,000
Long-term Debt, Maturities, Repayments of Principal in Year Two	$ 50,000

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Amount of borrowings as of the balance sheet date from the Federal Home Loan Bank, which are primarily used to cover shortages in the required reserve balance and liquidity shortages.

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Discloses the single interest rate [if] applicable to the advances from the Federal Home Loan Bank, by branch, as of the Balance Sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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