Fair Value Measurements (Summary Of Gains And Losses On Level 3 Assets And Liabilities) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Gains and Losses included in earnings for Level 3 assets & liabilities [Line Items]
Total gains or losses included in earnings	$ 3,955	$ 17	$ 8,425	$ (2,297)
Change in unrealized gains or losses relating to assets still held	4,538	920	9,006	(1,773)
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	147	(32)	149	522
Change in unrealized gains or losses relating to assets still held	730	871	730	871
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	17	1	180	11
Change in unrealized gains or losses relating to assets still held	17	1	180	11
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	3,791	48	8,096	(2,830)
Change in unrealized gains or losses relating to assets still held	$ 3,791	$ 48	$ 8,096	$ (2,655)