Allowance For Loan Losses, Allowance For Losses On Lending-Related Commitments And Impaired Loans (Summary Of Impaired Loans, Including Restructured Loans) (Details) (USD $) In Thousands	Sep. 30, 2011		Dec. 31, 2010		Sep. 30, 2010
Total impaired loans	$ 203,570	[1]	$ 202,274	[1]	$ 186,709	[1]
Allowance for loan losses related to impaired loans	28,447		30,626		27,289
Restructured loans	104,392		101,190		93,666
Impaired Financing Receivables With Related Allowance [Member]
Total impaired loans	83,191	[2]	115,381	[2]	89,338	[2]
Impaired Financing Receivables With No Related Allowance [Member]
Total impaired loans	$ 120,379		$ 86,893		$ 97,371

[1] Impaired loans are considered by the Company to be non-accrual loans, restructured loans or loans with principal and/or interest at risk, even if the loan is current with all payments of principal and interest.

[2] These impaired loans require an allowance for loan losses because the estimated fair value of the loans or related collateral is less than the recorded investment in the loans.