Fair Value Measurements (Summary of Gains and Losses on Level 3 Assets and Liabilities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Trading Activity, Gains and Losses, Net [Line Items]
Total gains or losses included in earnings	$ (820)	$ 13,954
Change in unrealized gains or losses relating to assets still held at period end	(1,720)	14,512
Loans Fees And Sales [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Total gains or losses included in earnings	(77)	(45)
Change in unrealized gains or losses relating to assets still held at period end	458	535
Other Non-Interest Income [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Total gains or losses included in earnings	(16)	150
Change in unrealized gains or losses relating to assets still held at period end	(1)	128
Investment Securities Gains (Losses), Net [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Total gains or losses included in earnings	(727)	13,849
Change in unrealized gains or losses relating to assets still held at period end	$ (2,177)	$ 13,849