Loans and Allowance for Loan Losses (Schedule Of Current, Accruing Past Due And Nonaccrual Loans) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	$ 22,878,747	$ 22,243,382
Accruing 30-89 Days Past Due	49,752	45,291
Accruing 90 Days or Greater Past Due	5,964	2,621
Total Accruing Past Due	55,716	47,912
Non-accrual	154,072	168,370
Total loans	23,088,535	22,459,664	$ 21,523,990
Deferred fees and costs, net	27,600	30,100	$ 29,100
Commercial Real Estate [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	7,456,308	7,327,763
Accruing 30-89 Days Past Due	11,419	9,223
Accruing 90 Days or Greater Past Due	340	135
Total Accruing Past Due	11,759	9,358
Non-accrual	39,628	57,647
Total loans	7,507,695	7,394,768
Investment Properties [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	5,901,061	5,726,307
Accruing 30-89 Days Past Due	5,451	2,284
Accruing 90 Days or Greater Past Due	0	0
Total Accruing Past Due	5,451	2,284
Non-accrual	14,149	23,040
Total loans	5,920,661	5,751,631
1-4 Family Properties [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	1,106,507	1,105,914
Accruing 30-89 Days Past Due	3,270	6,300
Accruing 90 Days or Greater Past Due	134	103
Total Accruing Past Due	3,404	6,403
Non-accrual	17,869	16,839
Total loans	1,127,780	1,129,156
Land Acquisition [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	448,740	495,542
Accruing 30-89 Days Past Due	2,698	639
Accruing 90 Days or Greater Past Due	206	32
Total Accruing Past Due	2,904	671
Non-accrual	7,610	17,768
Total loans	459,254	513,981
Commercial and Industrial [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	10,858,751	10,684,344
Accruing 30-89 Days Past Due	19,698	17,476
Accruing 90 Days or Greater Past Due	4,042	880
Total Accruing Past Due	23,740	18,356
Non-accrual	72,939	69,430
Total loans	10,955,430	10,772,130
Commercial, Financial and Agricultural [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	6,526,947	6,391,036
Accruing 30-89 Days Past Due	10,025	12,222
Accruing 90 Days or Greater Past Due	4,042	785
Total Accruing Past Due	14,067	13,007
Non-accrual	55,821	49,137
Total loans	6,596,835	6,453,180
Owner-Occupied [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	4,331,804	4,293,308
Accruing 30-89 Days Past Due	9,673	5,254
Accruing 90 Days or Greater Past Due	0	95
Total Accruing Past Due	9,673	5,349
Non-accrual	17,118	20,293
Total loans	4,358,595	4,318,950
Retail [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	4,563,688	4,231,275
Accruing 30-89 Days Past Due	18,635	18,592
Accruing 90 Days or Greater Past Due	1,582	1,606
Total Accruing Past Due	20,217	20,198
Non-accrual	41,505	41,293
Total loans	4,625,410	4,292,766
Home Equity Lines [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	1,633,322	1,667,552
Accruing 30-89 Days Past Due	6,604	5,882
Accruing 90 Days or Greater Past Due	271	0
Total Accruing Past Due	6,875	5,882
Non-accrual	16,912	16,480
Total loans	1,657,109	1,689,914
Consumer Mortgages [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	2,103,106	1,907,644
Accruing 30-89 Days Past Due	7,113	8,657
Accruing 90 Days or Greater Past Due	0	134
Total Accruing Past Due	7,113	8,791
Non-accrual	21,895	22,248
Total loans	2,132,114	1,938,683
Credit Cards [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	233,118	237,742
Accruing 30-89 Days Past Due	1,610	1,663
Accruing 90 Days or Greater Past Due	1,306	1,446
Total Accruing Past Due	2,916	3,109
Non-accrual	0	0
Total loans	236,034	240,851
Other Retail Loans [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	594,142	418,337
Accruing 30-89 Days Past Due	3,308	2,390
Accruing 90 Days or Greater Past Due	5	26
Total Accruing Past Due	3,313	2,416
Non-accrual	2,698	2,565
Total loans	$ 600,153	$ 423,318