Investment Securities (Other-Than-Temporary Impairment Charges on Securities Recognized in Earnings) (Details) (USD $) In Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Net impairment losses on securities recognized in earnings	$ 2,049	$ 825	$ 4,642
Residential Mortgage-Backed Securities [Member]
Net impairment losses on securities recognized in earnings	2,049		2,265
Trust Preferred Securities [Member]
Net impairment losses on securities recognized in earnings		$ 825	$ 2,377