Intangible Assets (Summary Of Gross Goodwill And Accumulated Impairment Losses And Write-Offs Detailed By Reportable Segments) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017		Jun. 30, 2016
Goodwill [Line Items]
Goodwill, Beginning balance	$ 191,371		$ 191,307
Additions	44,964	[1]	0
Goodwill, Ending balance	236,335		191,307
Regional Banking
Goodwill [Line Items]
Goodwill, Beginning balance	93,367		93,303
Additions	0	[1]	0
Goodwill, Ending balance	93,367		93,303
Fixed Income
Goodwill [Line Items]
Goodwill, Beginning balance	98,004		98,004
Additions	44,964	[1]	0
Goodwill, Ending balance	$ 142,968		$ 98,004

[1] See Note 2 - Acquisitions and Divestitures for further details regarding goodwill related to acquisitions.