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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 |  |  |

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