Loans And Allowance For Loan Losses (Summary Classification Of Held To Maturity Loan Portfolio) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Loans And Allowance For Loan Losses [Line Items]
Total loans	$ 13,626,592	$ 13,412,736
Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	4,852,408	4,776,365
Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	848,152	791,236
Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	2,727,349	2,643,374
Real Estate - Personal [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	2,009,203	2,010,397
Consumer [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	2,038,514	1,990,801
Revolving Home Equity [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	403,387	413,634
Consumer Credit Card [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	740,865	776,465
Overdrafts [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	$ 6,714	$ 10,464