Income Taxes - Reconciliation of Statutory Federal Income Tax Amount (Details) - USD ($) $ in Thousands |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2018 |
Sep. 30, 2018 |
Jun. 30, 2018 |
Mar. 31, 2018 |
Dec. 31, 2017 |
Sep. 30, 2017 |
Jun. 30, 2017 |
Mar. 31, 2017 |
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Income Tax Disclosure [Abstract] | |||||||||||
| Income (loss) before federal income taxes | $ 430,491 | $ 436,961 | $ (982,622) | ||||||||
| Expected income tax at statutory rate | 90,403 | 152,936 | (343,918) | ||||||||
| State income taxes | (511) | 2,299 | (5,883) | ||||||||
| Other differences | 1,078 | 5,731 | 4,293 | ||||||||
| Intraperiod tax allocation | 0 | 0 | (1,349) | ||||||||
| Remeasurement due to Tax Cut and Jobs Act | 0 | 190,034 | 0 | ||||||||
| Change in valuation allowance due to current year activity | (91,039) | (158,704) | 343,944 | ||||||||
| Change in valuation allowance due to Tax Cuts and Jobs Act | 0 | (190,487) | 0 | ||||||||
| Total income tax (benefit) expense provision | $ 0 | $ 0 | $ 0 | $ (69) | $ (954) | $ 2,763 | $ 0 | $ 0 | $ (69) | $ 1,809 | $ (2,913) |
| X | ||||||||||
- Definition Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Tax Cuts and Jobs Act of 2017, Amount No definition available.
|
| X | ||||||||||
- Definition Effective Income Tax Rate Reconciliation, Intra-period Tax Allocation, Amount No definition available.
|
| X | ||||||||||
- Definition Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Definition Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to increase (decrease) in the valuation allowance for deferred tax assets. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations, attributable to increase (decrease) in the income tax rates. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to other adjustments. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to state and local income tax expense (benefit). Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|