Income Taxes - Additional Information (Details) - USD ($) |
6 Months Ended | ||
|---|---|---|---|
Jun. 30, 2018 |
Jun. 30, 2017 |
Dec. 31, 2017 |
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| Income Tax Disclosure [Abstract] | |||
| Provision for federal income tax | $ 0 | $ 0 | |
| Unrecognized tax benefits that would impact effective tax rate | 4,500,000 | $ 4,500,000 | |
| Provision for income tax reflect any adjustment to previously assessed tax act enactment effect | $ 0 | ||
| X | ||||||||||
- Definition Amount of current and deferred federal income tax expense (benefit) attributable to income (loss) from continuing operations. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- References No definition available.
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| 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
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| X | ||||||||||
- Definition The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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