Intangible Assets (Summary Of Gross Goodwill And Accumulated Impairment Losses And Write-Offs Detailed By Reportable Segments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012	Dec. 31, 2011
Indefinite-lived Intangible Assets by Segment [Line Items]
Gross goodwill	$ 334,237	$ 334,237	$ 334,237	$ 333,654
Accumulated impairments	(114,123)	(114,123)	(114,123)	(114,123)
Accumulated divestiture related write-offs	(85,872)	(85,872)	(85,872)	(85,872)
Goodwill	134,242	134,242	134,242	133,659
Additions	0	583
Impairments	0	0
Divestitures	0	0
Net change in goodwill	0	583
Non Strategic [Member]
Indefinite-lived Intangible Assets by Segment [Line Items]
Gross goodwill	199,995	199,995	199,995	199,995
Accumulated impairments	(114,123)	(114,123)	(114,123)	(114,123)
Accumulated divestiture related write-offs	(85,872)	(85,872)	(85,872)	(85,872)
Goodwill	0	0	0	0
Additions	0	0
Impairments	0	0
Divestitures	0	0
Net change in goodwill	0	0
Regional Banking [Member]
Indefinite-lived Intangible Assets by Segment [Line Items]
Gross goodwill	36,238	36,238	36,238	36,238
Accumulated impairments	0	0	0	0
Accumulated divestiture related write-offs	0	0	0	0
Goodwill	36,238	36,238	36,238	36,238
Additions	0	0
Impairments	0	0
Divestitures	0	0
Net change in goodwill	0	0
Capital Markets [Member]
Indefinite-lived Intangible Assets by Segment [Line Items]
Gross goodwill	98,004	98,004	98,004	97,421
Accumulated impairments	0	0	0	0
Accumulated divestiture related write-offs	0	0	0	0
Goodwill	98,004	98,004	98,004	97,421
Additions	0	583
Impairments	0	0
Divestitures	0	0
Net change in goodwill	$ 0	$ 583