Note 7 - Loans (Details) - Allowance for Loan Losses by Portfolio Segment and Based on Impairment Method (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Loans individually evaluated for impairment
Individually Evaluated - Allowance	$ 14,495	$ 13,284
Individually Evaluated - Balance	189,311	200,780
Loans collectively evaluated for impairment
Collectively Evaluated - Allowance	154,643	160,605
Collectively Evaluated - Balance	8,112,971	7,883,783
Total allowance	169,138	173,889
Total balance	8,302,282	8,084,563
Commercial Loans [Member]
Loans individually evaluated for impairment
Individually Evaluated - Allowance	4,663	2,519
Individually Evaluated - Balance	30,013	31,968
Loans collectively evaluated for impairment
Collectively Evaluated - Allowance	60,119	62,584
Collectively Evaluated - Balance	2,199,867	2,266,756
Total allowance	64,782	65,103
Total balance	2,229,880	2,298,724
Real Estate Construction Loans [Member]
Loans individually evaluated for impairment
Individually Evaluated - Allowance	3,129	3,460
Individually Evaluated - Balance	33,859	34,420
Loans collectively evaluated for impairment
Collectively Evaluated - Allowance	7,497	8,539
Collectively Evaluated - Balance	219,973	187,281
Total allowance	10,626	11,999
Total balance	253,832	221,701
Commercial Mortgage Loans [Member]
Loans individually evaluated for impairment
Individually Evaluated - Allowance	6,165	6,584
Individually Evaluated - Balance	106,913	114,544
Loans collectively evaluated for impairment
Collectively Evaluated - Allowance	75,161	78,169
Collectively Evaluated - Balance	4,086,074	3,908,507
Total allowance	81,326	84,753
Total balance	4,192,987	4,023,051
Residential Mortgage And Equity Lines Member
Loans individually evaluated for impairment
Individually Evaluated - Allowance	538	721
Individually Evaluated - Balance	18,526	19,848
Loans collectively evaluated for impairment
Collectively Evaluated - Allowance	11,839	11,284
Collectively Evaluated - Balance	1,595,099	1,506,684
Total allowance	12,377	12,005
Total balance	1,613,625	1,526,532
Installment And Other Loans [Member]
Loans collectively evaluated for impairment
Collectively Evaluated - Allowance	27	29
Collectively Evaluated - Balance	11,958	14,555
Total allowance	27	29
Total balance	$ 11,958	$ 14,555

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- Definition

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=28368275&loc=SL6953423-111524

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- Definition

Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

+ References

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- Definition

The balance of financing receivables that were collectively evaluated for impairment.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (h)

-URI http://asc.fasb.org/extlink&oid=28368275&loc=SL6953423-111524

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The balance of financing receivables that were individually evaluated for impairment.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (h)

-URI http://asc.fasb.org/extlink&oid=28368275&loc=SL6953423-111524

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- Definition

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for 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 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.7(d))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 7

-Subparagraph d

-Article 9

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (b)(1)(ii)

-URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 6

-Section L

-Subsection 1

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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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