Loans And Allowance For Loan Losses (Loans Outstanding By Classification) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	$ 25,970,716	$ 24,812,795	$ 23,882,382
Deferred fees and costs, net	(24,143)	(25,331)	$ (26,000)
Total loans, net of deferred fees and costs	25,946,573	24,787,464
Total commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total commercial and industrial	12,781,206	12,023,650
Total loans	12,781,206	12,023,650
Total commercial and industrial | Commercial, financial, and agricultural
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total commercial and industrial	7,449,698	7,179,487
Total loans	7,449,698	7,179,487
Total commercial and industrial | Owner-occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total commercial and industrial	5,331,508	4,844,163
Total loans	5,331,508	4,844,163
Total commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total commercial real estate	6,564,491	6,935,288
Total loans	6,564,491	6,935,288
Total commercial real estate | Investment properties
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total commercial real estate	5,560,951	5,670,065
Total loans	5,560,951	5,670,065
Total commercial real estate | 1-4 family properties
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total commercial real estate	679,870	781,619
Total loans	679,870	781,619
Total commercial real estate | Land and development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total commercial real estate	323,670	483,604
Total loans	323,670	483,604
Total consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total consumer	6,625,019	5,853,857
Total loans	6,625,019	5,853,857
Total consumer | Consumer mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total consumer	2,934,235	2,633,503
Total loans	2,934,235	2,633,503
Total consumer | Home equity lines
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total consumer	1,515,796	1,514,227
Total loans	1,515,796	1,514,227
Total consumer | Credit cards
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total consumer	258,245	232,676
Total loans	258,245	232,676
Total consumer | Other consumer loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total consumer	1,916,743	1,473,451
Total loans	$ 1,916,743	$ 1,473,451