Derivative And Hedging Activities (Details 3) (USD $)	3 Months Ended						12 Months Ended	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012 Interest rate lock commitments (mortgage) [Member]	Mar. 31, 2011 Interest rate lock commitments (mortgage) [Member]	Mar. 31, 2012 Forward commitments (mortgage) [Member]	Mar. 31, 2011 Forward commitments (mortgage) [Member]	Dec. 31, 2011 Capital market fees [Member]	Mar. 31, 2012 Capital market fees [Member] Interest rate-related instruments - customer and mirror [Member]	Mar. 31, 2011 Capital market fees [Member] Interest rate-related instruments - customer and mirror [Member]	Mar. 31, 2012 Capital market fees [Member] Foreign currency exchange forwards [Member]	Mar. 31, 2011 Capital market fees [Member] Foreign currency exchange forwards [Member]
Gain (loss) on derivative instruments not designated as hedging instruments
Gain / (Loss) Recognized in Income	$ 1,000,000	$ (100,000)	$ 2,184,000	$ 1,272,000	$ 3,884,000	$ (6,162,000)	$ (2,000,000)	$ 755,000	$ (63,000)	$ (121,000)	$ (90,000)