Accounts and other receivables, net - Components of Accounts and Other Receivables (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Trade accounts receivable:
VAT and other receivables	$ 32.7	$ 45.9
Receivables from affiliates	3.1	0.8
Allowance for doubtful accounts	(3.9)	(3.9)
Total	313.9	325.7
Kronos | Trade accounts receivable
Trade accounts receivable:
Trade Accounts receivable	270.7	269.2
CompX | Trade accounts receivable
Trade accounts receivable:
Trade Accounts receivable	13.8	14.2
BMI/LandWell | Trade accounts receivable
Trade accounts receivable:
Trade Accounts receivable	$ 0.6	$ 0.3