Loans And Allowance For Loan Losses (Loans Outstanding By Classification) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total commercial real estate	$ 7,375,466	$ 6,926,602
Total commercial and industrial	10,791,432	10,267,719
Total retail	4,292,766	3,934,168
Total loans	22,459,664	21,128,489
Deferred fees and costs, net	(30,099)	(30,790)	$ (28,900)
Total loans, net of deferred fees and costs	22,429,565	21,097,699
Home Equity Lines [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total retail	1,689,914	1,683,998
Total loans	1,689,914	1,683,998
Consumer Mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total retail	1,938,683	1,694,061
Total loans	1,938,683	1,694,061
Credit Cards [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total retail	240,851	253,649
Total loans	240,851	253,649
Other Retail Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total retail	423,318	302,460
Total loans	423,318	302,460
Investment Properties [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total commercial real estate	5,751,631	5,206,674
Total loans	5,751,631	5,206,674
1-4 Family Properties [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total commercial real estate	1,109,854	1,133,882
Total loans	1,109,854	1,133,882
Land Acquisition [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total commercial real estate	513,981	586,046
Total loans	513,981	586,046
Commercial, Financial and Agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total commercial and industrial	6,472,482	6,182,312
Total loans	6,472,482	6,182,312
Owner-Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total commercial and industrial	4,318,950	4,085,407
Total loans	$ 4,318,950	$ 4,085,407