Loans And Allowance For Loan Losses (Summary Classification Of Held To Maturity Loan Portfolio) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Loans And Allowance For Loan Losses [Line Items]
Total loans	$ 12,697,870	$ 12,436,692
Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	4,575,081	4,397,893
Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	745,369	624,070
Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	2,395,933	2,355,544
Real Estate - Personal [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	1,903,969	1,915,953
Consumer [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	1,904,320	1,924,365
Revolving Home Equity [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	423,005	432,981
Consumer Credit Card [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	744,364	779,744
Overdrafts [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	$ 5,829	$ 6,142