Long-Term Debt - Long-Term Debt (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Long-term debt
Total debt	$ 965.0	$ 960.5
Less current maturities	7.8	9.5
Total long-term debt	957.2	951.0
VALHI, INC.
Long-term debt
Total debt	528.9	513.8
VALHI, INC. | Contran Credit Facility
Long-term debt
Total debt	278.9	263.8
VALHI, INC. | Notes Payable, Other Payables | Snake River
Long-term debt
Total debt	250.0	250.0
Kronos Worldwide, Inc. | 2014 Term Loan
Long-term debt
Total debt	335.9	338.0
WCS | Financing Capital Lease Obligation
Long-term debt
Total debt	64.0	65.6
Tremont | Promissory Note
Long-term debt
Total debt	14.5	17.1
BMI | Bank note payable
Long-term debt
Total debt	8.4	9.3
LandWell | Unsecured Debt
Long-term debt
Total debt	2.9	3.1
Other Subsidiary | Other
Long-term debt
Total debt	10.4	13.6
Subsidiary
Long-term debt
Total debt	$ 436.1	$ 446.7