Revenue - Disaggregation of Sales - Schedule of Disaggregates of Net Sales of our Chemicals Segment (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Disaggregation Of Revenue [Line Items]
Net sales	$ 556.3	$ 578.9	$ 1,819.9	$ 1,613.2
Chemicals
Disaggregation Of Revenue [Line Items]
Net sales	459.6	499.8	1,587.8	1,443.4
Point of Origin | Chemicals
Disaggregation Of Revenue [Line Items]
Net sales	459.6	499.8	1,587.8	1,443.4
Point of Origin | Chemicals | United States
Disaggregation Of Revenue [Line Items]
Net sales	330.3	297.6	980.4	787.5
Point of Origin | Chemicals | Germany
Disaggregation Of Revenue [Line Items]
Net sales	213.5	254.2	762.0	724.2
Point of Origin | Chemicals | Canada
Disaggregation Of Revenue [Line Items]
Net sales	105.1	88.6	313.1	288.8
Point of Origin | Chemicals | Belgium
Disaggregation Of Revenue [Line Items]
Net sales	76.0	69.6	256.3	212.0
Point of Origin | Chemicals | Norway
Disaggregation Of Revenue [Line Items]
Net sales	64.7	63.4	211.1	198.5
Point of Origin | Chemicals | Eliminations
Disaggregation Of Revenue [Line Items]
Net sales	(330.0)	(273.6)	(935.1)	(767.6)
Point of Destination | Chemicals
Disaggregation Of Revenue [Line Items]
Net sales	459.6	499.8	1,587.8	1,443.4
Point of Destination | Chemicals | Europe
Disaggregation Of Revenue [Line Items]
Net sales	197.5	248.0	731.6	712.1
Point of Destination | Chemicals | North America
Disaggregation Of Revenue [Line Items]
Net sales	182.5	174.3	558.4	476.9
Point of Destination | Chemicals | Other
Disaggregation Of Revenue [Line Items]
Net sales	$ 79.6	$ 77.5	$ 297.8	$ 254.4