Revenue - Disaggregation of Sales - Schedule of Disaggregates of Net Sales of our Chemicals Segment (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation Of Revenue [Line Items]
Net sales	$ 629.0	$ 509.0
Chemicals
Disaggregation Of Revenue [Line Items]
Net sales	562.9	465.0
Point of Origin | Chemicals
Disaggregation Of Revenue [Line Items]
Net sales	562.9	465.0
Point of Origin | Chemicals | United States
Disaggregation Of Revenue [Line Items]
Net sales	326.4	253.9
Point of Origin | Chemicals | Germany
Disaggregation Of Revenue [Line Items]
Net sales	276.5	231.2
Point of Origin | Chemicals | Canada
Disaggregation Of Revenue [Line Items]
Net sales	96.4	97.2
Point of Origin | Chemicals | Belgium
Disaggregation Of Revenue [Line Items]
Net sales	92.8	66.5
Point of Origin | Chemicals | Norway
Disaggregation Of Revenue [Line Items]
Net sales	78.4	71.0
Point of Origin | Chemicals | Eliminations
Disaggregation Of Revenue [Line Items]
Net sales	(307.6)	(254.8)
Point of Destination | Chemicals
Disaggregation Of Revenue [Line Items]
Net sales	562.9	465.0
Point of Destination | Chemicals | Europe
Disaggregation Of Revenue [Line Items]
Net sales	269.5	227.3
Point of Destination | Chemicals | North America
Disaggregation Of Revenue [Line Items]
Net sales	179.9	145.3
Point of Destination | Chemicals | Other
Disaggregation Of Revenue [Line Items]
Net sales	$ 113.5	$ 92.4