Loans (Net (Charge-Offs)/Recoveries, Segregated By Class Of Loans) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net (charge-offs)/recoveries, segregated by class of loans	$ (43,614)	$ (42,604)	$ (50,327)
Commercial And Industrial, Energy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net (charge-offs)/recoveries, segregated by class of loans	6
Commercial And Industrial, Other Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net (charge-offs)/recoveries, segregated by class of loans	(29,158)	(28,530)	(32,907)
Commercial Real Estate, Buildings, Land And Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net (charge-offs)/recoveries, segregated by class of loans	(8,980)	(5,928)	(5,612)
Commercial Real Estate, Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net (charge-offs)/recoveries, segregated by class of loans	(454)	(616)	(4,497)
Consumer Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net (charge-offs)/recoveries, segregated by class of loans	(2,293)	(2,059)	(1,526)
Consumer And Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net (charge-offs)/recoveries, segregated by class of loans	$ (2,735)	$ (5,471)	$ (5,785)