Income Taxes - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Apr. 30, 2020
Operating Loss Carryforwards [Line Items]
Income tax (benefit) expense	$ 0	$ 0	$ 0	$ 7,290	$ 315,815	$ (144,047)	$ (179,331)	$ 0	$ 7,290	$ (7,563)	$ (69)
Foreign tax credit carryforwards	523				943				523	943	2,009
Valuation allowance for deferred tax assets	(985,528)				$ (647,575)				(985,528)	(647,575)	(211,987)
Valuation allowance increase (decrease)									$ 338,000	$ 439,500	$ (86,800)
Testing period									3 years
Maximum percentage of company's securities allowed to be owned by third party												4.90%
Uncertain tax positions, liability	3,800								$ 3,800
Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carryforward	1,900,000								1,900,000
State
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards, subject to expiration	$ 441,000								$ 441,000