Junior Subordinated Debentures (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Common stock issued by trust owned	$ 6,900,000	$ 6,900,000
Total assets	11,563,355,000	11,668,710,000	9,381,372,000
Restricted core capital percentage	18.41%
(Loss) gain on junior subordinated debentures carried at fair value	(2,197,000)	4,980,000	6,482,000
Dodd-Frank Act [Member]
Total assets			$ 15,000,000,000