Basis of Presentation Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Jan. 01, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in ACL	$ 257,471		$ 166,209	$ 170,372	$ 169,410
Change in retained earnings	(1,040,646)		(1,079,391)
Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in ACL			58,349
Accounting Standards Update 2016-13 | Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in ACL		$ 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	$ 1,000		$ 3,200
Residential Mortgage | Accounting Standards Update 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in ACL for certain OBS credit exposure		(2,100)
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)