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, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Provision for Loan Losses	$ 800	$ 0	$ 300	$ (2,500)
Balance at end of period	596,440	610,277	596,440	610,277
Loans held for sale	139,122		139,122			$ 132,504
Commercial and industrial	13,035,251		13,035,251			13,162,955
Leasing	426,781		426,781			408,974
Owner occupied	7,141,360		7,141,360			7,351,548
Municipal	600,258		600,258			520,887
Construction and land development	2,213,465		2,213,465			1,986,408
Term	8,089,258		8,089,258			8,126,600
Provision for loan losses	(18,262)	54,643	(17,334)	109,669
Change In Allowance Covered By F D I C Indemnification	0	25	0	1,286
Allowance for Loan and Lease Losses, Write-offs	(42,359)	(26,471)	(93,595)	(70,666)
Allowance for Loan and Lease Losses, Recoveries of Bad Debts	11,162	15,509	68,038	45,607
Net loan and lease charge-offs	(31,197)	(10,962)	(25,557)	(25,059)
Reserve for unfunded lending commitments	81,389	79,377	81,389	79,377	$ 79,961	81,076	$ 95,472	$ 89,705
Provision for Unfunded Lending Commitments	(1,428)	16,095	(313)	10,328
Total allowance for credit losses	677,829	689,654	677,829	689,654
Consumer Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at end of period	46,474	44,467	46,474	44,467
Provision for loan losses	(2,466)	496	(2,533)	14,045
Change In Allowance Covered By F D I C Indemnification	0	0	0	96
Allowance for Loan and Lease Losses, Write-offs	(4,330)	(3,067)	(11,224)	(10,628)
Allowance for Loan and Lease Losses, Recoveries of Bad Debts	2,529	3,028	8,025	8,170
Net loan and lease charge-offs	(1,801)	(39)	(3,199)	(2,458)
Reserve for unfunded lending commitments	635	626	635	626	548	628	3,982	3,875
Provision for Unfunded Lending Commitments	(87)	3,356	(7)	3,249
Total allowance for credit losses	47,109	45,093	47,109	45,093
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at end of period	122,269	153,765	122,269	153,765
Construction and land development	2,213,465		2,213,465			1,986,408
Term	8,089,258		8,089,258			8,126,600
Provision for loan losses	6,621	34,187	38,491	57,350
Change In Allowance Covered By F D I C Indemnification	0	0	(57)	0
Allowance for Loan and Lease Losses, Write-offs	(1,068)	(3,320)	(5,637)	(14,135)
Allowance for Loan and Lease Losses, Recoveries of Bad Debts	4,162	3,332	21,331	9,238
Net loan and lease charge-offs	3,094	12	15,694	(4,897)
Reserve for unfunded lending commitments	17,172	24,299	17,172	24,299	18,639	21,517	38,689	37,485
Provision for Unfunded Lending Commitments	1,467	14,390	4,345	13,186
Total allowance for credit losses	139,441	178,064	139,441	178,064
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at end of period	427,697	412,045	427,697	412,045
Commercial and industrial	13,035,251		13,035,251			13,162,955
Leasing	426,781		426,781			408,974
Owner occupied	7,141,360		7,141,360			7,351,548
Municipal	600,258		600,258			520,887
Provision for loan losses	(22,417)	19,960	(53,292)	38,274
Change In Allowance Covered By F D I C Indemnification	0	25	57	1,190
Allowance for Loan and Lease Losses, Write-offs	(36,961)	(20,084)	(76,734)	(45,903)
Allowance for Loan and Lease Losses, Recoveries of Bad Debts	4,471	9,149	38,682	28,199
Net loan and lease charge-offs	(32,490)	(10,935)	(38,052)	(17,704)
Reserve for unfunded lending commitments	63,582	54,452	63,582	54,452	$ 60,774	$ 58,931	$ 52,801	$ 48,345
Provision for Unfunded Lending Commitments	(2,808)	(1,651)	(4,651)	(6,107)
Total allowance for credit losses	$ 491,279	$ 466,497	$ 491,279	$ 466,497