Long-Term Debt - Long-Term Debt (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Long-term debt
Total debt	$ 559.5	$ 653.0
Less current maturities	1.8	3.1
Total long-term debt	557.7	649.9
VALHI, INC. | Contran Credit Facility
Long-term debt
Total debt	121.4	172.9
Kronos Worldwide, Inc. | 3.75% Senior Secured Notes due September 15, 2025 | Kronos International, Inc
Long-term debt
Total debt	424.1	448.8
BMI | Bank loan | Western Alliance Bank
Long-term debt
Total debt		15.4
LandWell | Unsecured Debt | Western Alliance Bank
Long-term debt
Total debt	12.9	13.5
Other Subsidiary | Other
Long-term debt
Total debt	1.1	2.4
Subsidiary
Long-term debt
Total debt	$ 438.1	$ 480.1