Note 5 - Loans (Details Textual) $ in Thousands	12 Months Ended
Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Servicing Asset	$ 367,600
Impaired Financing Receivable, Recorded Investment	115,074	$ 133,810
Impaired Financing Receivable, Average Recorded Investment	131,019	162,945	$ 190,226
Impaired Financing Receivable, Interest Income, Accrual Method	$ 3,462	$ 3,997	5,339
Percentage Of Charge Off To Contractual Balances For Impaired Loans	8.40%	22.40%
Financing Receivable, Modifications, Subsequent Default, Number of Contracts	0
Loans and Leases Receivable, Impaired, Commitment to Lend	$ 0
Minimum [Member]
Period Loan Is In Payment Default	60 days
Maximum [Member]
Period Loan Is In Payment Default	90 days
Nonaccrual Loans [Member]
Impaired Financing Receivable, Recorded Investment	$ 49,700	$ 52,100
Accruing Troubled Debt Restructuring [Member]
Impaired Financing Receivable, Recorded Investment	65,400	81,700
Financing Receivable, Modifications, Recorded Investment	65,400	81,700
Allowance for Credit Losses, Change in Method of Calculating Impairment	1,300	2,000
Non-accruing Troubled Debt Restructuring [Member]
Financing Receivable, Modifications, Recorded Investment	29,700	39,900
Allowance for Credit Losses, Change in Method of Calculating Impairment	1,100	5,400
Residential Portfolio Segment [Member]
Servicing Asset	133,300
Repossessed Assets	3,600	2,000
Commercial Real Estate Portfolio Segment [Member]
Servicing Asset	112,800
Impaired Financing Receivable, Average Recorded Investment	81,905	100,118	114,248
Impaired Financing Receivable, Interest Income, Accrual Method	2,214	2,708	3,735
Commercial Construction Loans [Member]
Servicing Asset	83,100
Commercial Portfolio Segment [Member]
Servicing Asset	38,400
Impaired Financing Receivable, Average Recorded Investment	21,199	23,960	26,128
Impaired Financing Receivable, Interest Income, Accrual Method	767	546	$ 878
Real Estate Loan [Member]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	7,800,000	6,800,000
Commercial Loans [Member]
Loans Pledged with Federal Reserve Bank	$ 30,000	$ 71,300

Amount of the collateral pledged in support of loans with Federal Reserve Bank's Discount Window.

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Percentage of charge-off to contractual balances for impaired loans.

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Period Loan Is In Payment Default

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Amount of allowance for credit losses related to receivables which had been measured under a general allowance for credit losses methodology that are now identified as troubled debt restructurings.

+ References

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Amount of the collateral pledged in support of federal home loan bank advances outstanding.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 470
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The amount of the outstanding recorded investment related to financing receivables that have been modified by troubled debt restructurings.

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Number of financing receivables that have been modified by troubled debt restructurings within the previous 12 months and for which there was a payment default.

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Carrying amount as of the balance sheet date of all assets obtained in full or partial satisfaction of a debt arrangement through foreclosure proceedings or defeasance; includes real and personal property; equity interests in corporations, partnerships, and joint ventures; and beneficial interests in trusts.

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Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

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Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

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Reflects the unfunded portion of contractual agreements to lend funds to borrowers for loans whose terms have been modified by troubled debt restructuring.

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Aggregate amount of servicing assets that are subsequently measured at fair value and servicing assets that are subsequently measured using the amortization method.

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