Revenue - disaggregation of sales - Schedule of Disaggregates of Net Sales of our Chemicals Segment (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Revenue - disaggregation of sales [Line Items]
Net sales	$ 530.6	$ 492.7
Chemicals
Revenue - disaggregation of sales [Line Items]
Net sales	478.8	426.3
Point of Origin | Chemicals
Revenue - disaggregation of sales [Line Items]
Net sales	478.8	426.3
Point of Origin | Chemicals | Eliminations
Revenue - disaggregation of sales [Line Items]
Net sales	(204.2)	(247.1)
Point of Origin | Chemicals | Operating Segment | United States
Revenue - disaggregation of sales [Line Items]
Net sales	240.9	255.8
Point of Origin | Chemicals | Operating Segment | Germany
Revenue - disaggregation of sales [Line Items]
Net sales	212.2	186.0
Point of Origin | Chemicals | Operating Segment | Canada
Revenue - disaggregation of sales [Line Items]
Net sales	89.3	90.9
Point of Origin | Chemicals | Operating Segment | Norway
Revenue - disaggregation of sales [Line Items]
Net sales	71.0	71.9
Point of Origin | Chemicals | Operating Segment | Belgium
Revenue - disaggregation of sales [Line Items]
Net sales	69.6	68.8
Point of Destination | Chemicals
Revenue - disaggregation of sales [Line Items]
Net sales	478.8	426.3
Point of Destination | Chemicals | Operating Segment | Europe
Revenue - disaggregation of sales [Line Items]
Net sales	214.9	201.1
Point of Destination | Chemicals | Operating Segment | North America
Revenue - disaggregation of sales [Line Items]
Net sales	166.0	148.6
Point of Destination | Chemicals | Operating Segment | Other
Revenue - disaggregation of sales [Line Items]
Net sales	$ 97.9	$ 76.6