Loans And Allowance For Loan Losses (Summary Classification Of Held To Maturity Loan Portfolio) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Loans And Allowance For Loan Losses [Line Items]
Total loans	$ 9,376,915	$ 9,177,478
Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	2,993,067	2,808,265
Business [Member] | Commercial [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	2,993,067	2,808,265
Real Estate - Construction And Land [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	346,048	386,598
Real Estate - Construction And Land [Member] | Commercial [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	346,048	386,598
Real Estate - Business [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	2,190,838	2,180,100
Real Estate - Business [Member] | Commercial [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	2,190,838	2,180,100
Real Estate - Personal [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	1,501,170	1,428,777
Real Estate - Personal [Member] | Personal Banking [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	1,501,170	1,428,777
Consumer [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	1,162,532	1,114,889
Consumer [Member] | Personal Banking [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	1,162,532	1,114,889
Revolving Home Equity [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	447,601	463,587
Revolving Home Equity [Member] | Personal Banking [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	447,601	463,587
Consumer Credit Card [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	732,388	788,701
Consumer Credit Card [Member] | Personal Banking [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	732,388	788,701
Overdrafts [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	3,271	6,561
Overdrafts [Member] | Personal Banking [Member]
Loans And Allowance For Loan Losses [Line Items]
Total loans	$ 3,271	$ 6,561