Note 7 - Loans (Details) - Aging of Loan Portfolio (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans, 30-59 Days Past Due	$ 27,746	$ 36,359
Loans, 60-89 Days Past Due	1,788	5,879
Loans, Greater than 90 Days Past Due	787
Non-accrual Loans	80,324	70,163
Loans, Past Due	110,645	112,401
Loans, Not Past Due	9,114,152	8,801,679
Loans	9,224,797	8,914,080
Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans, 30-59 Days Past Due	3,530	11,595
Loans, 60-89 Days Past Due	50	1,238
Loans, Greater than 90 Days Past Due	787
Non-accrual Loans	12,086	6,983
Loans, Past Due	16,453	19,816
Loans, Not Past Due	2,418,097	2,362,677
Loans	2,434,550	2,382,493
Real Estate Construction Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans, 30-59 Days Past Due		1,416
Non-accrual Loans	17,126	19,963
Loans, Past Due	17,126	21,379
Loans, Not Past Due	328,434	277,275
Loans	345,560	298,654
Commercial Mortgage Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans, 30-59 Days Past Due	22,041	17,654
Loans, 60-89 Days Past Due	1,738	3,909
Non-accrual Loans	43,079	35,606
Loans, Past Due	66,858	57,169
Loans, Not Past Due	4,596,193	4,429,274
Loans	4,663,051	4,486,443
Residential Mortgage and Equity Lines [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans, 30-59 Days Past Due	2,175	5,634
Loans, 60-89 Days Past Due		732
Non-accrual Loans	8,033	7,611
Loans, Past Due	10,208	13,977
Loans, Not Past Due	1,766,058	1,728,961
Loans	1,776,266	1,742,938
Installment And Other Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans, 30-59 Days Past Due		60
Loans, Past Due		60
Loans, Not Past Due	5,370	3,492
Loans	$ 5,370	$ 3,552

The financing receivable recorded investment not in past due.

No definition available.

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Data Type:	xbrli:monetaryItemType
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- Definition

Financing receivables that are less than 60 days past due but more than 29 days past due.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 7A

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953401-111524

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- Definition

Financing receivables that are less than 90 days past due but more than 59 days past due.

+ References

+ Details

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- Definition

Financing receivables that are equal to or greater than 90 days past due.

+ References

+ Details

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- Definition

Recorded investment in financing receivables that are on nonaccrual status as of the balance sheet date.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 7

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5111-111524

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- Definition

Recorded Investment in financing receivables that are past due at the balance sheet date.

+ References

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- Definition

Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4428-111522

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