Loans (Allowance For Possible Loan Losses Disaggregated On The Basis Of Impairment Methodology) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial and Industrial	$ 4,042,852	$ 3,916,867	$ 3,723,244
Commercial Real Estate	3,034,884	3,020,827	3,212,694
Consumer Real Estate	761,286	762,809	784,368
Consumer and Other	304,472	312,536	325,122
Unearned Discounts	(16,781)	(17,910)	(20,348)
Total loans	8,126,713	7,995,129	8,025,080
Loans Individually Evaluated For Impairment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial and Industrial	178,521	189,139	269,900
Commercial Real Estate	226,266	241,451	295,214
Consumer Real Estate	2,577	2,470
Consumer and Other	535	554
Total loans	407,899	433,614	565,114
Loans Collectively Evaluated For Impairment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial and Industrial	3,864,331	3,727,728	3,453,344
Commercial Real Estate	2,808,618	2,779,376	2,917,480
Consumer Real Estate	758,709	760,339	784,368
Consumer and Other	303,937	311,982	325,122
Unearned Discounts	(16,781)	(17,910)	(20,348)
Total loans	$ 7,718,814	$ 7,561,515	$ 7,459,966

The total value of other non major installment loans (gross) made by financial institutions to consumers, the proceeds of which are used by individuals (borrowers) for purchases such as household goods, vacations, and other consumer items. Such loans are generally repaid in periodic payments over a predetermined time period, are generally secured by the item purchased and may be either direct to the borrower (direct paper) or to the dealer (indirect paper or retail sales contract).

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The total gross amount of money lent to individual customers including construction financing, residential mortgage loans, and home equity lines of credit.

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- Definition

Reflects the aggregate gross carrying amount of all categories of loans and leases held in portfolio, after deducting deferred income, but before deducting the allowance for losses on loans and leases.

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- Definition

Reflects the gross carrying amount of unpaid loans issued to nonfinancial and nonagricultural businesses for uses other than for real property.

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- Definition

Reflects the sum of the gross carrying amounts of unpaid loans issued to businesses to acquire, develop, construct, improve, or refinance land or a building. Includes [but is not limited to] commercial mortgage loans, which are secured by a [legal] security interest in real property [commercial building or business real property] which thereby serves as collateral securing repayment of the loan; and construction financing, which is an obligation generally in the form of a [promissory] note, used for the funding of construction projects.

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

-Publisher AICPA

-Name Audit and Accounting Guide (AAG)

-Number AAG-DEP

-Chapter 8

-Paragraph 51, 52, 53

-IssueDate 2006-05-01

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6965416&loc=d3e5066-111524

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 60

-Paragraph 47

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: 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(a))

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

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Statement of Position (SOP)

-Number 01-6

-Paragraph 13

-Subparagraph e

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 9

-Section 03

-Paragraph 7

-Subparagraph a

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.1(c))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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