Accounts payable and accrued liabilities - Schedule of Accounts Payable and Accrued Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Accounts payable:
Accounts payable	$ 179.2	$ 231.3
Current accrued liabilities:
Employee benefits	35.9	38.0
Deferred income	26.3	25.9
Accrued development costs	23.4	25.2
Accrued sales discounts and rebates	14.0	25.1
Accrued severance cost	3.8	8.8
Operating lease liabilities	$ 3.9	$ 4.2
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Total	Total
Accrued environmental	$ 2.7	$ 2.8
Interest	13.9	14.2
Other	50.9	57.2
Total	355.7	434.1
Kronos Worldwide
Accounts payable:
Accounts payable	172.5	224.0
CompX
Accounts payable:
Accounts payable	3.9	2.7
BMI/LandWell
Accounts payable:
Accounts payable	2.1	2.6
Other
Accounts payable:
Distributions payable to noncontrolling interest	0.7	2.0
Contran \| Other payables
Accounts payable:
Payables to affiliates	$ 1.7	$ 1.4

Sum of the carrying values as of the balance sheet date of obligations incurred through that date and due within one year (or the operating cycle, if longer), including liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received, taxes, interest, rent and utilities, accrued salaries and bonuses, payroll taxes and fringe benefits.

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Period Type:	instant

- Definition

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).