Loans And Allowance For Loan Losses (Summary Classification Of Held To Maturity Loan Portfolio) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Loans And Allowance For Loan Losses [Line Items]
Total loans	$ 9,247,971	$ 9,177,478
Business [Member] | Commercial [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	2,920,237	2,808,265
Real Estate - Construction And Land [Member] | Commercial [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	376,642	386,598
Real Estate - Business [Member] | Commercial [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	2,203,686	2,180,100
Real Estate - Personal [Member] | Personal Banking [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	1,458,467	1,428,777
Consumer [Member] | Personal Banking [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	1,113,481	1,114,889
Revolving Home Equity [Member] | Personal Banking [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	448,169	463,587
Consumer Credit Card [Member] | Personal Banking [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	723,759	788,701
Overdrafts [Member] | Personal Banking [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	$ 3,530	$ 6,561