Fair Value Measurements (Summary Of Gains And Losses On Level 3 Assets And Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Trading Activity, Gains and Losses, Net [Line Items]
Total gains or losses included in earnings	$ 4,114	$ 1,062
Change in unrealized gains or losses relating to assets still held	4,123	1,544
Loan Fees And Sales [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Total gains or losses included in earnings	(9)	(369)
Change in unrealized gains or losses relating to assets still held		113
Other Non-Interest Income [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Total gains or losses included in earnings	(2)	6
Change in unrealized gains or losses relating to assets still held	(2)	6
Investment Securities Gains (Losses), Net [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Total gains or losses included in earnings	4,125	1,425
Change in unrealized gains or losses relating to assets still held	$ 4,125	$ 1,425