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, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Gains and Losses included in earnings for Level 3 assets & liabilities [Line Items]
Total gains or losses included in earnings	$ (4,683)	$ (1,051)	$ (18,177)	$ (2,578)
Change in unrealized gains or losses relating to assets still held	(4,682)	(214)	(17,746)	(3,478)
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	2,547	112	2,088	399
Change in unrealized gains or losses relating to assets still held	2,547	935	2,547	935
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	267	13	240	41
Change in unrealized gains or losses relating to assets still held	268	27	212	55
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	(7,497)	(1,176)	(20,505)	(3,018)
Change in unrealized gains or losses relating to assets still held	$ (7,497)	$ (1,176)	$ (20,505)	$ (4,468)