Commitments and Contingencies - Future Minimum Payments under Non-cancellable Operating Leases (Parenthetical) (Detail) $ in Millions	Dec. 31, 2017 USD ($)
Future Minimum Payments Under Non Cancelable Operating Leases With Initial Terms Of One Year Or More [Line Items]
Future minimum lease payments	$ 54.7
Leverkusen TiO2 production facility | Chemicals
Future Minimum Payments Under Non Cancelable Operating Leases With Initial Terms Of One Year Or More [Line Items]
Future minimum lease payments	$ 17.0