Intangible Assets (Summary Of Gross Goodwill And Accumulated Impairment Losses And Write-Offs Detailed By Reportable Segments) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Goodwill [Line Items]
Goodwill, Beginning balance	$ 191,371	$ 191,307
Additions	0	0
Goodwill, Ending balance	191,371	191,307
Regional Banking [Member]
Goodwill [Line Items]
Goodwill, Beginning balance	93,367	93,303
Additions	0	0
Goodwill, Ending balance	93,367	93,303
Fixed Income [Member]
Goodwill [Line Items]
Goodwill, Beginning balance	98,004	98,004
Additions	0	0
Goodwill, Ending balance	$ 98,004	$ 98,004