Investment Securities (Schedule Of Realized Gross Gains And Losses On Sale From Available For Sale Portfolio ) (Details) (USD $)	3 Months Ended				6 Months Ended
	Jun. 30, 2011		Jun. 30, 2010		Jun. 30, 2011		Jun. 30, 2010
Investment Securities
Gross gains on sales of securities	$ 1,000		$ 76,000		$ 9,422,000		$ 196,000
Gross (losses) on sales of securities			(1,000)		(8,623,000)		(1,000)
Net gain/(loss) on sales of securities	1,000	[1]	75,000	[1]	799,000	[1]	195,000	[1]
Venture capital investments							(1,838,000)	[2]
Net other than temporary impairment ("OTTI") recorded							(188,000)	[3]
Total securities gain/(loss)	1,000		75,000		799,000		(1,831,000)
Proceeds from sales from available for sale portfolio			$ 35,400,000		$ 458,300,000		$ 35,700,000

[1] Proceeds related to these sales were $35.4 million for the three months ended June 30, 2010, and were $458.3 million and $35.7 million for the six months ended June 30, 2011 and 2010, respectively. Proceeds from sales during second quarter 2011 were immaterial.

[2] Generally includes write-offs and/or unrealized fair value adjustments related to venture capital investments.

[3] OTTI recorded in 2010 is related to equity securities.