Loans Schedule of accounts, Notes, Loans and Financing Receivables (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Commercial	$ 9,160,729	$ 8,750,109	$ 8,806,340
Loans and Leases Receivable, Gross, Consumer, Mortgage	1,059,735	1,050,584	1,006,673
Loans and Leases Receivable, Gross, Consumer, Installment, Other	3,092,501	2,738,656	2,733,754
Loans and Leases Receivable, Gross, Consumer, Home Equity	1,398,266	1,311,932	1,299,063
Loans and Leases Receivable, Gross, Consumer, Revolving, Credit Card	160,113	148,313	145,113
Loans and Leases Receivable, Gross, Consumer, Lease Financing	339,936	239,551	199,907
FDIC Indemnification Asset	30,746	61,827	69,986
Loans and Leases Receivable, Gross	15,242,026	14,300,972	14,260,836
Allowance for loan losses	(140,077)	(141,252)	(143,835)
Net loans	15,101,949	14,159,720	14,117,001
Originated Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Commercial	7,626,166	6,648,279	6,420,369
Loans and Leases Receivable, Gross, Consumer, Mortgage	605,998	529,253	487,283
Loans and Leases Receivable, Gross, Consumer, Installment, Other	2,277,533	1,727,925	1,647,095
Loans and Leases Receivable, Gross, Consumer, Home Equity	1,062,013	920,066	889,372
Loans and Leases Receivable, Gross, Consumer, Revolving, Credit Card	160,113	148,313	145,113
Loans and Leases Receivable, Gross, Consumer, Lease Financing	339,936	239,551	199,907
Loans and Leases Receivable, Gross	12,071,759	10,213,387	9,789,139
Allowance for loan losses	(90,883)	(96,484)	(98,291)
Net loans	11,980,876	10,116,903	9,690,848
Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Commercial	1,272,244	1,725,970	1,963,746
Loans and Leases Receivable, Gross, Consumer, Mortgage	410,065	470,652	466,594
Loans and Leases Receivable, Gross, Consumer, Installment, Other	809,820	1,004,569	1,080,298
Loans and Leases Receivable, Gross, Consumer, Home Equity	252,975	294,424	306,783
Loans and Leases Receivable, Gross	2,745,104	3,495,615	3,817,421
Allowance for loan losses	(6,206)	(741)	0
Net loans	2,738,898	3,494,874	3,817,421
Covered Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Commercial	262,319	375,860	422,225
Loans and Leases Receivable, Gross, Consumer, Mortgage	43,672	50,679	52,796
Loans and Leases Receivable, Gross, Consumer, Installment, Other	5,148	6,162	6,361
Loans and Leases Receivable, Gross, Consumer, Home Equity	83,278	97,442	102,908
FDIC Indemnification Asset	30,746	61,827	69,986
Loans and Leases Receivable, Gross, Carrying Amount, Covered	425,163	591,970	654,276
Loans and Leases Receivable, Allowance, Covered	(42,988)	(44,027)	(45,544)
Loans and Leases Receivable, Net Reported Amount, Covered	$ 382,175	$ 547,943	$ 608,732