Percentage of voting equity interests acquired at the acquisition date in the business combination.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479328/805-10-50-2

Name:	us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

Organization and basis of presentation - Additional Information (Details)	Mar. 31, 2025	Jul. 16, 2024	Jul. 15, 2024
Kronos \| Louisiana Pigment Company, L.P. (LPC)
Organization and basis of presentation
Percentage held through wholly-owned subsidiary		50.00%
Percentage acquired		50.00%	50.00%
Contran \| Valhi Incorporation
Organization and basis of presentation
Parent company ownership interest	91.00%