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, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Gains and Losses included in earnings for Level 3 assets & liabilities [Line Items]
Total gains or losses included in earnings	$ 2,893	$ 1,945	$ (15,284)	$ (633)
Change in unrealized gains or losses relating to assets still held	5,459	2,880	(14,834)	(1,532)
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	591	(112)	2,679	287
Change in unrealized gains or losses relating to assets still held	3,137	823	3,137	823
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	(87)	37	153	78
Change in unrealized gains or losses relating to assets still held	(87)	37	125	93
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	2,389	2,020	(18,116)	(998)
Change in unrealized gains or losses relating to assets still held	$ 2,409	$ 2,020	$ (18,096)	$ (2,448)