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Marketable securities - Schedule of Marketable Securities (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2025	Dec. 31, 2024
Marketable Securities [Line Items]
Market value, Noncurrent assets	$ 18,900	$ 28,015
Fair Value, Inputs, Level 1 [Member] | Valhi Inc | Common stock
Marketable Securities [Line Items]
Market value, Noncurrent assets	18,900	28,015
Cost or amortized cost, Noncurrent assets	24,347	24,347
Unrealized gain (loss), net Noncurrent assets	$ (5,447)	$ 3,668

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- Definition

Amount of unrealized gain (loss) on non current marketable securities.

+ References

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- Definition

Cost of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). Excludes equity method investment and investment in equity security without readily determinable fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(1))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

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- Definition

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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- Definition

Amount of investment in marketable security, classified as noncurrent.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

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