Loans And Allowance For Credit Losses (Summary Of ALLL And Outstanding Loan Balances According To The Company's Impairment Method) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired Financing Receivable, Average Recorded Investment	$ 602,095	$ 863,084	$ 578,481	$ 877,419
Impaired Financing Receivable, Interest Income, Accrual Method	13,911	18,098	25,982	44,419
Allowance for loan losses: Individually evaluated for impairment	(50,748)		(50,748)			$ (41,713)
Allowance for loan losses: Collectively evaluated for impairment	557,488		557,488			560,150
Allowance for loan losses: Purchased loans with evidence of credit deterioration	1,139		1,139			2,800
Allowance for loan losses: Total	609,375	675,907	609,375	675,907	$ 620,013	604,663	$ 736,953	$ 746,291
Outstanding loan balances: Individually evaluated for impairment	499,666		499,666			521,909
Outstanding loan balances: Collectively evaluated for impairment	39,371,898		39,371,898			39,362,450
Financing Receivable Allowance For Credit Losses and Receivables Acquired With Deteriorated Credit Quality	152,420		152,420			179,299
Total loans	40,023,984		40,023,984			40,063,658
Commercial and Industrial Sector [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired Financing Receivable, Average Recorded Investment	174,911	194,683	155,584	188,136
Impaired Financing Receivable, Interest Income, Accrual Method	2,831	4,212	4,255	6,802
Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired Financing Receivable, Average Recorded Investment	144,613	232,662	142,817	236,250
Impaired Financing Receivable, Interest Income, Accrual Method	3,186	4,532	6,970	9,286
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Individually evaluated for impairment	(37,037)		(37,037)			(28,627)
Allowance for loan losses: Collectively evaluated for impairment	400,472		400,472			382,552
Allowance for loan losses: Purchased loans with evidence of credit deterioration	261		261			1,335
Allowance for loan losses: Total	437,770	442,965	437,770	442,965	442,072	412,514	477,701	469,213
Outstanding loan balances: Individually evaluated for impairment	275,607		275,607			259,207
Outstanding loan balances: Collectively evaluated for impairment	21,034,441		21,034,441			21,105,217
Financing Receivable Allowance For Credit Losses and Receivables Acquired With Deteriorated Credit Quality	68,618		68,618			79,940
Total loans	21,378,666		21,378,666			21,444,364
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired Financing Receivable, Average Recorded Investment	35,562	61,957	36,215	64,265
Impaired Financing Receivable, Interest Income, Accrual Method	1,628	1,394	2,177	4,932
Allowance for loan losses: Total	125,796	187,940	125,796	187,940	131,615	145,009	208,149	216,012
Consumer Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired Financing Receivable, Average Recorded Investment	4,176	7,314	4,463	7,854
Impaired Financing Receivable, Interest Income, Accrual Method	230	421	516	930
Allowance for loan losses: Individually evaluated for impairment	(10,382)		(10,382)			(9,059)
Allowance for loan losses: Collectively evaluated for impairment	34,721		34,721			37,508
Allowance for loan losses: Purchased loans with evidence of credit deterioration	706		706			573
Allowance for loan losses: Total	45,809	45,002	45,809	45,002	$ 46,326	47,140	$ 51,103	$ 61,066
Outstanding loan balances: Individually evaluated for impairment	90,220		90,220			95,267
Outstanding loan balances: Collectively evaluated for impairment	8,422,221		8,422,221			8,395,371
Financing Receivable Allowance For Credit Losses and Receivables Acquired With Deteriorated Credit Quality	12,876		12,876			15,648
Total loans	8,525,317		8,525,317			8,506,286
Commercial Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired Financing Receivable, Average Recorded Investment	320,532	436,615	299,422	434,001
Impaired Financing Receivable, Interest Income, Accrual Method	6,017	8,744	11,225	16,088
Term [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired Financing Receivable, Average Recorded Investment	144,054	245,827	142,439	260,749
Impaired Financing Receivable, Interest Income, Accrual Method	5,063	6,618	10,038	20,568
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired Financing Receivable, Average Recorded Investment	179,616	307,784	178,654	325,014
Impaired Financing Receivable, Interest Income, Accrual Method	6,691	8,012	12,215	25,500
Allowance for loan losses: Individually evaluated for impairment	(3,329)		(3,329)			(4,027)
Allowance for loan losses: Collectively evaluated for impairment	122,295		122,295			140,090
Allowance for loan losses: Purchased loans with evidence of credit deterioration	172		172			892
Allowance for loan losses: Total	125,796		125,796			145,009
Outstanding loan balances: Individually evaluated for impairment	133,839		133,839			167,435
Outstanding loan balances: Collectively evaluated for impairment	9,915,236		9,915,236			9,861,862
Financing Receivable Allowance For Credit Losses and Receivables Acquired With Deteriorated Credit Quality	70,926		70,926			83,711
Total loans	10,120,001		10,120,001			$ 10,113,008
Home Equity Line of Credit [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired Financing Receivable, Average Recorded Investment	25,400	25,854	24,948	25,470
Impaired Financing Receivable, Interest Income, Accrual Method	416	372	821	774
One Through Four Family Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired Financing Receivable, Average Recorded Investment	69,874	82,353	68,464	81,909
Impaired Financing Receivable, Interest Income, Accrual Method	534	512	1,041	1,052
Construction And Other Consumer Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired Financing Receivable, Average Recorded Investment	2,497	3,164	2,529	3,166
Impaired Financing Receivable, Interest Income, Accrual Method	22	36	64	74
Revolving Credit Facility [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired Financing Receivable, Average Recorded Investment	0	0	1	5
Impaired Financing Receivable, Interest Income, Accrual Method	1	1	100	1
Consumer Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired Financing Receivable, Average Recorded Investment	101,947	118,685	100,405	118,404
Impaired Financing Receivable, Interest Income, Accrual Method	1,203	1,342	2,542	2,831
Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired Financing Receivable, Average Recorded Investment	1,008	9,270	1,021	9,615
Impaired Financing Receivable, Interest Income, Accrual Method	$ 0	$ 0	$ 0	$ 0