Loans And Allowance For Loan Losses (Allowance For Loan Losses And Related Loan Balance Disaggregated On The Basis Of Impairment Methodology) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Loans And Allowance For Loan Losses [Line Items]
Impaired loans	$ 9,972	$ 10,758
Impaired loans	132,691	139,255
Allowance For Loan Losses [Member]
Loans And Allowance For Loan Losses [Line Items]
Impaired loans	9,972	10,758
All other loans	171,560	173,774
Loans Outstanding [Member]
Loans And Allowance For Loan Losses [Line Items]
Impaired loans	132,691	139,255
All other loans	9,115,280	9,038,223
Commercial [Member] | Allowance For Loan Losses [Member]
Loans And Allowance For Loan Losses [Line Items]
Impaired loans	5,221	6,668
All other loans	112,253	115,829
Commercial [Member] | Loans Outstanding [Member]
Loans And Allowance For Loan Losses [Line Items]
Impaired loans	102,005	108,167
All other loans	5,398,560	5,266,796
Personal Banking [Member] | Allowance For Loan Losses [Member]
Loans And Allowance For Loan Losses [Line Items]
Impaired loans	4,751	4,090
All other loans	59,307	57,945
Personal Banking [Member] | Loans Outstanding [Member]
Loans And Allowance For Loan Losses [Line Items]
Impaired loans	30,686	31,088
All other loans	$ 3,716,720	$ 3,771,427