Summary of Significant Accounting Policies Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Held to maturity allowance for credit loss	$ (63)	$ (67)
Retained Earnings (Accumulated Deficit)	2,520,144	2,458,920
Off-Balance Sheet, Credit Loss, Liability	50,776	47,776		$ 21,907
Allowance for Loan Losses [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss	352,938	383,702		201,371
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Off-Balance Sheet, Credit Loss, Liability	$ 50,776	$ 47,776		$ 21,907
Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Off-Balance Sheet, Credit Loss, Liability			$ 18,690
Accounting Standards Update 2016-13 | Allowance for Loan Losses [Member] | Cumulative Effect, Period Of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss			112,457
Accounting Standards Update 2016-13 | SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Cumulative Effect, Period Of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Off-Balance Sheet, Credit Loss, Liability			$ 18,690