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Property, Plant And Equipment - Additional Information (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Property Plant And Equipment [Abstract]      
Depreciation expense related to property, plant and equipment $ 8,142 $ 8,154 $ 8,307
Elimination of Assets and Accumulated depreciation $ 4,057 $ 6,317 $ 16,652