Annual report pursuant to Section 13 and 15(d)

Quarterly Financial Information (Unaudited) - Additional Information (Detail)

v3.10.0.1
Quarterly Financial Information (Unaudited) - Additional Information (Detail) - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
Dec. 31, 2018
Sep. 30, 2018
Jun. 30, 2018
Mar. 31, 2018
Dec. 31, 2017
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]                      
Increase (decrease) to gross profit from inventory lower of cost or market adjustment $ (2.8) $ (1.2) $ 0.2 $ 0.9 $ 2.8 $ 0.7 $ (0.7) $ 0.8 $ (2.9) $ 3.6 $ 1.7
Loss from liquidation of LIFO inventory layers $ 0.1       $ 1.0       0.1 1.0 1.9
Loss on extinguishment of debt     $ 0.5     $ 0.2     $ 0.5 $ 0.2 $ 23.4