Loans And Allowance For Loan Losses (Loans Outstanding By Classification) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total commercial real estate	$ 7,365,974	$ 7,394,768
Total commercial and industrial	11,551,943	10,772,130
Total retail	4,964,465	4,292,766
Total loans	23,882,382	22,459,664
Deferred fees and costs, net	(25,991)	(30,099)	$ (30,800)
Total loans, net of deferred fees and costs	23,856,391	22,429,565
Home Equity Lines [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total retail	1,617,265	1,689,914
Total loans	1,617,265	1,689,914
Consumer Mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total retail	2,296,604	1,938,683
Total loans	2,296,604	1,938,683
Credit Cards [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total retail	232,413	240,851
Total loans	232,413	240,851
Other Retail Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total retail	818,183	423,318
Total loans	818,183	423,318
Investment Properties [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total commercial real estate	5,932,619	5,751,631
Total loans	5,932,619	5,751,631
1-4 Family Properties [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total commercial real estate	1,023,821	1,129,156
Total loans	1,023,821	1,129,156
Land Acquisition [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total commercial real estate	409,534	513,981
Total loans	409,534	513,981
Commercial, Financial and Agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total commercial and industrial	6,915,927	6,453,180
Total loans	6,915,927	6,453,180
Owner-Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total commercial and industrial	4,636,016	4,318,950
Total loans	$ 4,636,016	$ 4,318,950