Impairment of Long-Lived Assets - Additional Information (Detail) $ in Thousands |
12 Months Ended |
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Dec. 31, 2017
USD ($)
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| Impairment Or Disposal Of Tangible Assets Disclosure [Abstract] | |
| Estimated aggregate remaining fair value of long-lived assets impaired during current period | $ 8,953 |
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- Definition Estimated aggregate fair value of long lived assets impaired during current period. No definition available.
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- References No definition available.
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