Note 7 - Loans (Details) - Allowance For Loan Losses By Portfolio Segment And Based On Impairment Method (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Loans individually evaluated for impairment
Individually Evaluated - Allowance	$ 12,779	$ 12,183
Individually Evaluated - Balance	211,077	248,597
Loans collectively evaluated for impairment
Collectively Evaluated - Allowance	166,954	171,139
Collectively Evaluated - Balance	7,483,296	7,180,550
Total allowance	179,733	183,322
Total balance	7,694,373	7,429,147
Commercial Loans Member
Loans individually evaluated for impairment
Individually Evaluated - Allowance	1,568	1,467
Individually Evaluated - Balance	20,263	23,922
Loans collectively evaluated for impairment
Collectively Evaluated - Allowance	62,811	64,634
Collectively Evaluated - Balance	2,190,498	2,103,185
Total allowance	64,379	66,101
Total balance	2,210,761	2,127,107
Real Estate Construction Loans [Member]
Loans individually evaluated for impairment
Individually Evaluated - Allowance	4,995	8,158
Individually Evaluated - Balance	35,288	42,133
Loans collectively evaluated for impairment
Collectively Evaluated - Allowance	8,760	14,859
Collectively Evaluated - Balance	118,375	138,817
Total allowance	13,755	23,017
Total balance	153,663	180,950
Commercial Mortgage Loans [Member]
Loans individually evaluated for impairment
Individually Evaluated - Allowance	5,342	1,336
Individually Evaluated - Balance	137,970	165,885
Loans collectively evaluated for impairment
Collectively Evaluated - Allowance	84,336	81,137
Collectively Evaluated - Balance	3,771,589	3,602,567
Total allowance	89,678	82,473
Total balance	3,909,559	3,768,452
Residential Mortgage And Equity Lines Member
Loans individually evaluated for impairment
Individually Evaluated - Allowance	874	1,222
Individually Evaluated - Balance	17,556	16,657
Loans collectively evaluated for impairment
Collectively Evaluated - Allowance	11,018	10,481
Collectively Evaluated - Balance	1,389,991	1,323,425
Total allowance	11,892	11,703
Total balance	1,407,547	1,340,082
Installment And Other Loans Member
Loans collectively evaluated for impairment
Collectively Evaluated - Allowance	29	28
Collectively Evaluated - Balance	12,843	12,556
Total allowance	29	28
Total balance	$ 12,843	$ 12,556

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- Definition

A valuation allowance for financing receivables that are expected to be uncollectible.

+ 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 (c)(1)

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

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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

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

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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- Definition

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 representing an agreement for an unconditional promise by the maker to pay the entity (holder) a definite sum of money at a future date. Such amount may include accrued interest receivable in accordance with the terms of the note. The note also may contain provisions and related items including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among a myriad of other features and characteristics. Excludes amounts related to receivables held-for-sale.

+ 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 210.9-03.10(3))

-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 10

-Subparagraph 3

-Article 9

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