Accounts and other receivables, net - Components of Accounts and Other Receivables (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Trade accounts receivable:
VAT and other receivables	$ 33.7	$ 45.9
Refundable income taxes	1.3	1.3
Allowance for doubtful accounts	(4.0)	(3.9)
Total	388.7	327.8
Trade Accounts Receivable | Kronos
Trade accounts receivable:
Trade Accounts receivable	338.4	269.2
Trade Accounts Receivable | CompX
Trade accounts receivable:
Trade Accounts receivable	18.1	14.2
Trade Accounts Receivable | BMI/LandWell
Trade accounts receivable:
Trade Accounts receivable	0.7	0.3
Contran | Trade Items
Trade accounts receivable:
Receivables from affiliates		0.2
Other | Trade Items
Trade accounts receivable:
Receivables from affiliates	$ 0.5	$ 0.6