Loans And Allowance For Credit Losses (Summary Of Major Portfolio Segment And Specific Loan Class) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014
Financing Receivable, Allowance for Credit Losses [Line Items]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Provision for Loan Losses	$ 1,100	$ 800	$ 1,900	$ 300
Balance at end of period	597,185	596,440	597,185	596,440
Loans held for sale	160,287		160,287			$ 149,880
Commercial and industrial	13,542,752		13,542,752			13,211,481
Leasing	438,933		438,933			441,666
Owner occupied	6,889,674		6,889,674			7,150,028
Municipal	752,960		752,960			675,839
Construction and land development	2,147,212		2,147,212			1,841,502
Term	9,302,712		9,302,712			8,514,401
Provision for loan losses	(18,825)	(18,262)	(95,462)	(17,334)
Change In Allowance Covered By F D I C Indemnification		0		0
Allowance for Loan and Lease Losses, Write-offs	(53,763)	(42,359)	(159,502)	(93,595)
Allowance for Loan and Lease Losses, Recoveries of Bad Debts	23,778	11,162	55,177	68,038
Net loan and lease charge-offs	(29,985)	(31,197)	(104,325)	(25,557)
Reserve for unfunded lending commitments	61,615	81,389	61,615	81,389	$ 64,780	74,838	$ 79,961	$ 81,076
Provision for Unfunded Lending Commitments	3,165	(1,428)	13,223	(313)
Total allowance for credit losses	658,800	$ 677,829	658,800	$ 677,829
Loans Receivable, Gross, Commercial, Real Estate	11,449,924		11,449,924			10,355,903
Loans and Leases Receivable, Gross, Consumer, Home Equity	2,581,068		2,581,068			2,416,357
Loans and Leases Receivable, Gross, Consumer, Mortgage	5,784,583		5,784,583			5,382,099
Loans and Leases Receivable, Gross, Consumer, Construction	453,235		453,235			385,240
Loans and Leases Receivable, Gross, Consumer, Revolving, Credit Card	457,910		457,910			443,780
Loans and Leases Receivable, Gross, Consumer, Other	188,681		188,681			187,149
Loans and Leases Receivable, Gross	42,539,720		42,539,720			40,649,542
Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable before Fees, Gross	21,624,319		21,624,319			21,479,014
Consumer Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable before Fees, Gross	$ 9,465,477		$ 9,465,477			$ 8,814,625