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Property, Plant and Equipment - Additional Information (Detail)
$ in Millions
12 Months Ended
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Business
Property, Plant and Equipment [Abstract]      
Property, plant and equipment acquired $ 14.0   $ 58.1
Number of businesses acquired | Business     2
Depreciation expense $ 28.9 $ 24.7 $ 20.1