Loans And Allowance For Loan Losses (Summary Classification Of Held To Maturity Loan Portfolio) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Loans And Allowance For Loan Losses [Line Items]
Total loans	$ 9,638,645	$ 9,177,478
Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	3,098,908	2,808,265
Business [Member] | Commercial [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	3,098,908	2,808,265
Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	335,113	386,598
Real Estate - Construction And Land [Member] | Commercial [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	335,113	386,598
Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	2,193,206	2,180,100
Real Estate - Business [Member] | Commercial [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	2,193,206	2,180,100
Real Estate - Personal [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	1,556,754	1,428,777
Real Estate - Personal [Member] | Personal Banking [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	1,556,754	1,428,777
Consumer [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	1,243,400	1,114,889
Consumer [Member] | Personal Banking [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	1,243,400	1,114,889
Revolving Home Equity [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	453,527	463,587
Revolving Home Equity [Member] | Personal Banking [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	453,527	463,587
Consumer Credit Card [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	748,885	788,701
Consumer Credit Card [Member] | Personal Banking [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	748,885	788,701
Overdrafts [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	8,852	6,561
Overdrafts [Member] | Personal Banking [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	$ 8,852	$ 6,561