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Property, Plant and Equipment, Net - Additional Information (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Property Plant And Equipment [Abstract]      
Depreciation expenses $ 6,441 $ 5,276 $ 3,611
Depletion expense 3 13 14
Interest expense capitalized $ 132 $ 1,808 $ 453