Loans (Schedule of Accounts, Notes, Loans and Financing Receivables) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Commercial	$ 9,222,609	$ 9,128,591	$ 8,987,337
Loans and Leases Receivable, Gross, Consumer, Mortgage	1,058,642	1,061,043	1,051,756
Loans and Leases Receivable, Gross, Consumer, Installment, Other	3,222,762	3,162,493	2,784,407
Loans and Leases Receivable, Gross, Consumer, Home Equity	1,417,232	1,417,330	1,324,939
Loans and Leases Receivable, Gross, Consumer, Revolving, Credit Card	160,766	164,478	147,917
Loans and Leases Receivable, Gross, Consumer, Lease Financing	388,873	370,179	257,509
FDIC Indemnification Asset	20,005us-gaap_FDICIndemnificationAsset	22,033us-gaap_FDICIndemnificationAsset	54,748us-gaap_FDICIndemnificationAsset
Loans and Leases Receivable, Gross, Carrying Amount, Covered		312,659
Loans and Leases Receivable, Gross	15,490,889	15,326,147	14,608,613
Allowance for loan losses	(146,552)	(143,649)	(145,060)
Net loans	15,344,337	15,182,498	14,463,553
Originated Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Commercial	8,031,892	7,830,085	7,083,192
Loans and Leases Receivable, Gross, Consumer, Mortgage	639,980	625,283	555,971
Loans and Leases Receivable, Gross, Consumer, Installment, Other	2,500,288	2,393,451	1,835,522
Loans and Leases Receivable, Gross, Consumer, Home Equity	1,134,238	1,110,336	946,802
Loans and Leases Receivable, Gross, Consumer, Revolving, Credit Card	160,766	164,478	147,917
Loans and Leases Receivable, Gross, Consumer, Lease Financing	388,873	370,179	257,509
Loans and Leases Receivable, Gross	12,856,037	12,493,812	10,826,913
Allowance for loan losses	(97,545)	(95,696)	(92,116)
Net loans	12,758,492	12,398,116	10,734,797
Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Commercial	1,011,170	1,086,899	1,562,878
Loans and Leases Receivable, Gross, Consumer, Mortgage	378,192	394,484	446,374
Loans and Leases Receivable, Gross, Consumer, Installment, Other	717,693	764,168	943,354
Loans and Leases Receivable, Gross, Consumer, Home Equity	217,824	233,629	283,309
Loans and Leases Receivable, Gross	2,324,879	2,479,180	3,235,915
Allowance for loan losses	(7,493)	(7,457)	(2,974)
Net loans	2,317,386	2,471,723	3,232,941
Covered Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Commercial	179,547	211,607	341,267
Loans and Leases Receivable, Gross, Consumer, Mortgage	40,470	41,276	49,411
Loans and Leases Receivable, Gross, Consumer, Installment, Other	4,781	4,874	5,531
Loans and Leases Receivable, Gross, Consumer, Home Equity	65,170	73,365	94,828
FDIC Indemnification Asset	20,005	22,033	54,748
Loans and Leases Receivable, Gross, Carrying Amount, Covered	309,973	353,155	545,785
Loans and Leases Receivable, Allowance, Covered	(41,514)	(40,496)	(49,970)
Loans and Leases Receivable, Net Reported Amount, Covered	$ 268,459	$ 312,659	$ 495,815

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Carrying amount of receivable assets originating from the indemnification agreement with the Federal Deposit Insurance Corporation (FDIC), in which the FDIC is to partially cover losses.

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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

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Amount of allowance for loan and lease losses covered by loss sharing agreements.

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Amount before allowance of commercial loans and leases receivable includes, but not limited to, commercial and industrial loans, agricultural loans, mortgage loans, promissory notes, interbank and other loans to financial institutions, draws against credit facilities, trade financing, lease financings. 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.

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Amount before allowance of revolving, open-end loan, extended under a line of credit and secured by the borrower's residential property. 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.

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- Definition

Amount before allowance of other consumer installment 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.

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Amount before allowance of consumer lease agreements. 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.

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Amount before allowance of consumer mortgage. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes subordinated loans such as home equity lines of credit and loans and leases covered under loss sharing agreements.

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- Definition

Amount before allowance of credit card loans issued to individuals. 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.

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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

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Aggregate gross carrying amount of loans and leases receivable covered by loss sharing agreements.

+ References

No definition available.

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

+ References

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Net carrying amount of loans and leases receivable covered by loss sharing agreements.

+ References

No definition available.

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