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