Fair Value Measurements (Summary Of Gains And Losses On Level 3 Assets And Liabilities) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Gains and Losses included in earnings for Level 3 assets & liabilities [Line Items]
Total gains or losses included in earnings	$ (5,305)	$ (2,785)	$ (7,602)	$ (6,040)
Change in unrealized gains or losses relating to assets still held	(4,434)	(1,995)	(7,078)	(5,677)
Loans Fees And Sales [Member]
Gains and Losses included in earnings for Level 3 assets & liabilities [Line Items]
Total gains or losses included in earnings	(115)	86	407	613
Change in unrealized gains or losses relating to assets still held	756	876	756	876
Other Non-Interest Income [Member]
Gains and Losses included in earnings for Level 3 assets & liabilities [Line Items]
Total gains or losses included in earnings	8	50	19	(8)
Change in unrealized gains or losses relating to assets still held	8	50	19	(8)
Investment Securities Gains (Losses), Net [Member]
Gains and Losses included in earnings for Level 3 assets & liabilities [Line Items]
Total gains or losses included in earnings	(5,198)	(2,921)	(8,028)	(6,645)
Change in unrealized gains or losses relating to assets still held	$ (5,198)	$ (2,921)	$ (7,853)	$ (6,545)