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Other Financial Statement Information - Additional Information (Detail) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Nov. 02, 2016
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Dec. 31, 2016
Inventory Disclosure [Abstract]            
Cost of inventories for certain materials using LIFO method   $ 26.2   $ 26.2   $ 28.6
Expense (benefit) charge to earnings from LIFO inventory changes   $ 0.1 $ (0.2) $ 0.2 $ (0.3)  
Name of plaintiff       Altalink, L.P.    
Complaint filling date       November 2016    
Estimated damages from defendants $ 56.0