Commitments And Contingencies (Gains (Losses) Related To Derivative Instruments Not Designated As Hedging Instruments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Trading Activity, Gains and Losses, Net [Line Items]
Other non-interest income	$ 21,720	$ 18,564	$ 18,091	$ 39,551	$ 30,957	$ 19,843	$ 20,031	$ 20,437	$ 15,921	$ 16,015	$ 17,043
Other non-interest expense									50,158	44,182	45,014
Not Designated As Hedging Instrument [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Trading gains, net										1,984
Other non-interest income										$ 369