Fair Value Measurement Of Assets And Liabilities (Gains And Losses From Fair Value Changes) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010	Dec. 31, 2009
Gains and Losses from Fair Value Changes [Line Items]
Gains and losses from fair value changes included in income before income taxes	$ (6,998,000)		$ 1,052,000	$ (7,849,000)
Transfers from held-to-maturity to available for sale	18,300,000
Net Impairment Losses On Securities [Member] | Available For Sale Securities [Member]
Gains and Losses from Fair Value Changes [Line Items]
Gains and losses from fair value changes included in income before income taxes	(19,968,000)	[1]	(4,642,000)	(6,352,000)
Trading Gains (Losses), Net [Member] | Trading Securities [Member]
Gains and Losses from Fair Value Changes [Line Items]
Gains and losses from fair value changes included in income before income taxes	1,015,000		(1,056,000)	5,394,000
Trading Gains (Losses), Net [Member] | Junior Subordinated Debentures [Member]
Gains and Losses from Fair Value Changes [Line Items]
Gains and losses from fair value changes included in income before income taxes	1,256,000		(5,841,000)	(15,828,000)
Gains on Sales of Loans, Net [Member] | Loans Held For Sale [Member]
Gains and Losses from Fair Value Changes [Line Items]
Gains and losses from fair value changes included in income before income taxes	$ 10,699,000		$ 12,591,000	$ 8,937,000

[1] Includes $18.3 million related to impaired trust preferred securities transferred from held-to-maturity to available for sale at December 31, 2011.