Accounts and other receivables, net - Accounts and Other Receivables, Net (Detail) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Accounts Notes And Loans Receivable [Line Items]
Allowance for doubtful accounts	$ (4.3)	$ (3.8)
Total	347.1	291.6
Trade receivables
Accounts Notes And Loans Receivable [Line Items]
Accounts and other receivables	320.9	269.2
Recoverable VAT and other receivables
Accounts Notes And Loans Receivable [Line Items]
Accounts and other receivables	23.2	24.3
Refundable income taxes
Accounts Notes And Loans Receivable [Line Items]
Refundable income taxes	1.5	1.3
Valhi \| Income taxes receivable from Valhi
Accounts Notes And Loans Receivable [Line Items]
Receivables from affiliates, other	5.6
Other Affiliates \| Other
Accounts Notes And Loans Receivable [Line Items]
Receivables from affiliates, other	$ 0.2	$ 0.6

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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