Long-Term Debt - Long-Term Debt (Detail) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Long-term debt
Total debt	$ 980.8	$ 960.5
Less current maturities	9.4	9.5
Total long-term debt	971.4	951.0
VALHI, INC.
Long-term debt
Total debt	526.5	513.8
VALHI, INC. | Contran Credit Facility
Long-term debt
Total debt	276.5	263.8
VALHI, INC. | Notes Payable, Other Payables | Snake River
Long-term debt
Total debt	250.0	250.0
Kronos Worldwide, Inc. | Revolving North American credit facility
Long-term debt
Total debt	9.2
Kronos Worldwide, Inc. | 2014 Term Loan
Long-term debt
Total debt	337.5	338.0
WCS | Financing Capital Lease Obligation
Long-term debt
Total debt	65.2	65.6
Tremont | Promissory Note
Long-term debt
Total debt	17.1	17.1
BMI | Bank note payable
Long-term debt
Total debt	9.1	9.3
LandWell | Unsecured Debt
Long-term debt
Total debt	3.1	3.1
Other Subsidiary | Other
Long-term debt
Total debt	13.1	13.6
Subsidiary
Long-term debt
Total debt	$ 454.3	$ 446.7