Income Taxes (Tax Carryforwards) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Operating Loss Carryforwards [Line Items]
Deferred Tax Asset Balance, Gross	$ 387,372	$ 290,474
Valuation Allowance	(19,191)	(18,445)
Total deferred tax assets	368,181	$ 272,029
Federal | Net Operating Loss | 2029-2032
Operating Loss Carryforwards [Line Items]
Deferred Tax Asset Balance, Gross	19,903
Valuation Allowance	(15,852)
Total deferred tax assets	4,051
Pre-Tax Earnings Necessary to Realize	19,292
State | Net Operating Loss | 2023-2034
Operating Loss Carryforwards [Line Items]
Deferred Tax Asset Balance, Gross	15,783
Valuation Allowance	(3,339)
Total deferred tax assets	12,444
Pre-Tax Earnings Necessary to Realize	1,346,109
State | Other Credits | 2023-2030
Operating Loss Carryforwards [Line Items]
Deferred Tax Asset Balance, Gross	12,733
Valuation Allowance	0
Total deferred tax assets	$ 12,733