Revenue - Disaggregation of Sales - Schedule of Disaggregates of Net Sales of our Chemicals Segment (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation Of Revenue [Line Items]
Net sales	$ 634.6	$ 525.3	$ 1,263.6	$ 1,034.3
Chemicals
Disaggregation Of Revenue [Line Items]
Net sales	565.3	478.6	1,128.2	943.6
Point of Origin | Chemicals
Disaggregation Of Revenue [Line Items]
Net sales	565.3	478.6	1,128.2	943.6
Point of Origin | Chemicals | United States
Disaggregation Of Revenue [Line Items]
Net sales	323.7	236.0	650.1	489.9
Point of Origin | Chemicals | Germany
Disaggregation Of Revenue [Line Items]
Net sales	272.0	238.8	548.5	470.0
Point of Origin | Chemicals | Canada
Disaggregation Of Revenue [Line Items]
Net sales	111.6	103.0	208.0	200.2
Point of Origin | Chemicals | Belgium
Disaggregation Of Revenue [Line Items]
Net sales	87.5	75.9	180.3	142.4
Point of Origin | Chemicals | Norway
Disaggregation Of Revenue [Line Items]
Net sales	68.0	64.1	146.4	135.1
Point of Origin | Chemicals | Eliminations
Disaggregation Of Revenue [Line Items]
Net sales	(297.5)	(239.2)	(605.1)	(494.0)
Point of Destination | Chemicals
Disaggregation Of Revenue [Line Items]
Net sales	565.3	478.6	1,128.2	943.6
Point of Destination | Chemicals | Europe
Disaggregation Of Revenue [Line Items]
Net sales	264.6	236.8	534.1	464.1
Point of Destination | Chemicals | North America
Disaggregation Of Revenue [Line Items]
Net sales	196.0	157.3	375.9	302.6
Point of Destination | Chemicals | Other
Disaggregation Of Revenue [Line Items]
Net sales	$ 104.7	$ 84.5	$ 218.2	$ 176.9