Long-Term Debt - Long-Term Debt (Detail) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Long-term debt
Total debt	$ 992.6	$ 965.0
Less current maturities	7.6	7.8
Total long-term debt	985.0	957.2
VALHI, INC.
Long-term debt
Total debt	532.7	528.9
VALHI, INC. | Contran Credit Facility
Long-term debt
Total debt	282.7	278.9
VALHI, INC. | Notes Payable, Other Payables | Snake River
Long-term debt
Total debt	250.0	250.0
Kronos Worldwide, Inc. | North American Revolving Credit Facility
Long-term debt
Total debt	16.3
Kronos Worldwide, Inc. | 2014 Term Loan
Long-term debt
Total debt	334.9	335.9
Waste Control Specialists | Financing Capital Lease Obligation
Long-term debt
Total debt	63.1	64.0
Tremont | Promissory Note
Long-term debt
Total debt	14.5	14.5
BMI | Bank note payable | Meadows Bank
Long-term debt
Total debt		8.4
BMI | Bank loan | Western Alliance Bank
Long-term debt
Total debt	18.7
LandWell | Unsecured Debt
Long-term debt
Total debt	2.7	2.9
Other Subsidiary | Other
Long-term debt
Total debt	9.7	10.4
Subsidiary
Long-term debt
Total debt	$ 459.9	$ 436.1