Long-Term Debt - Long-Term Debt (Detail) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Long-term debt
Total debt	$ 943.8	$ 934.1
Less current maturities	9.1	9.3
Total long-term debt	934.7	924.8
VALHI, INC.
Long-term debt
Total debt	487.2	473.7
VALHI, INC. | Notes Payable, Other Payables | Snake River
Long-term debt
Total debt	250.0	250.0
VALHI, INC. | Contran Credit Facility
Long-term debt
Total debt	237.2	223.7
Kronos Worldwide, Inc. | 2014 Term Loan
Long-term debt
Total debt	344.3	345.9
WCS | Financing Capital Lease Obligation
Long-term debt
Financing capital lease	66.4	67.1
Tremont | Promissory Note
Long-term debt
Total debt	17.3	17.4
BMI | Bank note payable
Long-term debt
Total debt	9.9	10.3
LandWell | Unsecured Debt
Long-term debt
Total debt	3.1	3.1
Other Subsidiary | Other
Long-term debt
Total debt	15.6	16.6
Subsidiary
Long-term debt
Total debt	$ 456.6	$ 460.4