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Property, Plant and Equipment - Additional Information (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Property, Plant and Equipment [Abstract]      
Amounts of assets held under finance leases $ 4.4 $ 3.0  
Depreciation charges 13.5 13.0 $ 10.6
Estimated additional cost to complete work in progress $ 9.5 $ 2.4