Basis of Presentation Narrative (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Jan. 01, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
ACL - loans	$ 256,727	$ 277,567
Change in retained earnings	(1,258,499)	(1,120,781)
Increase in ACL for certain OBS credit exposure	4,300	5,300
Accounting Standards Update 2016-13 | Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
ACL - loans			$ 58,300
Change in retained earnings			43,800
Increase in deferred tax assets			12,400
Residential Mortgage
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in ACL for certain OBS credit exposure	$ 1,100	$ 1,100
Residential Mortgage | Accounting Standards Update 2016-13 | Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in ACL for certain OBS credit exposure			$ (2,100)