| Income Taxes - Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands | 12 Months Ended | ||
|---|---|---|---|
| Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
| Components of Income Tax Expense (Benefit), Continuing Operations [Abstract] | |||
| Current | $ 35 | $ (12,786) | $ (71,768) | 
| Deferred | 500 | 217 | 28,392 | 
| Total income tax expense (benefit) | $ 535 | $ (12,569) | $ (43,376) | 
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- References No definition available. 
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- Definition Amount of current income tax expense (benefit) pertaining to taxable income (loss) from continuing operations. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- 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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