Intangible Assets (Summary Of Gross Goodwill And Accumulated Impairment Losses And Write-Offs Detailed By Reportable Segments) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	[1]	Dec. 31, 2014
Goodwill [Line Items]
Goodwill	$ 191,371	$ 145,932	$ 191,307		$ 145,932
Additions	64	0
Impairments	0	0
Divestitures	0	0
Regional Banking [Member]
Goodwill [Line Items]
Goodwill	93,367	47,928	93,303		47,928
Additions	64	0
Impairments	0	0
Divestitures	0	0
Fixed Income [Member]
Goodwill [Line Items]
Goodwill	98,004	98,004	$ 98,004		$ 98,004
Additions	0	0
Impairments	0	0
Divestitures	$ 0	$ 0

[1] The increase in goodwill was related to the TAF acquisition in fourth quarter 2015.