Loans And Allowance For Loan Losses (Summary Classification Of Held To Maturity Loan Portfolio) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Loans And Allowance For Loan Losses [Line Items]
Total loans	$ 13,572,509	$ 13,412,736
Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	4,888,011	4,776,365
Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	846,904	791,236
Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	2,710,595	2,643,374
Real Estate - Personal [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	2,013,437	2,010,397
Consumer [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	1,975,521	1,990,801
Revolving Home Equity [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	396,542	413,634
Consumer Credit Card [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	736,766	776,465
Overdrafts [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	$ 4,733	$ 10,464