Loans And Allowance For Loan Losses (Summary Classification Of Held To Maturity Loan Portfolio) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Loans And Allowance For Loan Losses [Line Items]
Total loans	$ 13,745,492	$ 13,412,736
Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	4,834,037	4,776,365
Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	921,609	791,236
Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	2,700,174	2,643,374
Real Estate - Personal [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	2,029,302	2,010,397
Consumer [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	2,113,438	1,990,801
Revolving Home Equity [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	391,308	413,634
Consumer Credit Card [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	752,379	776,465
Overdrafts [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	$ 3,245	$ 10,464