v3.10.0.1
Inventories - Narrative (Detail) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2017
Inventory Disclosure [Abstract]        
Cost of sales LIFO adjustment $ 9.1 $ (11.0) $ 5.4 $ (15.0)