Long-term debt (Detail) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Long-term debt
Total debt	$ 498.2	$ 546.5
Less current maturities	0.8	0.7
Total long-term debt	497.4	545.8
VALHI, INC. \| Contran Credit Facility
Long-term debt
Total debt	62.6	93.4
Kronos Worldwide, Inc. \| 9.50% Senior Secured Notes due March 15, 2029 \| Kronos International, Inc
Long-term debt
Total debt	289.8
Kronos Worldwide, Inc. \| 3.75% Senior Secured Notes due September 15, 2025 \| Kronos International, Inc
Long-term debt
Total debt	80.2	440.9
Kronos Worldwide, Inc. \| Subordinated, unsecured term loan from Contran \| Contran
Long-term debt
Total debt	53.7
LandWell \| Unsecured Debt \| Western Alliance Bank
Long-term debt
Total debt	11.9	12.2
Subsidiary
Long-term debt
Total debt	$ 435.6	$ 453.1

Amount of long-term debt and lease obligation, classified as noncurrent.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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