Long-Term Debt - Long-Term Debt (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Long-term debt
Total debt	$ 929.0	$ 752.5
Less current maturities	11.8	10.7
Total long-term debt	917.2	741.8
Other Subsidiary Debt
Long-term debt
Other	11.0	10.5
Subsidiary Debt
Long-term debt
Total subsidiary debt	461.3	296.0
VALHI, INC.
Long-term debt
Total Valhi debt	467.7	456.5
VALHI, INC. | Snake River | Notes Payable, Other Payables
Long-term debt
Debt instrument	250.0	250.0
VALHI, INC. | Contran
Long-term debt
Debt instrument	217.7	206.5
Kronos Worldwide, Inc. | Term Loan
Long-term debt
Debt instrument	348.3
Kronos Worldwide, Inc. | Note Payable | Contran
Long-term debt
Debt instrument		170.0
Kronos Worldwide, Inc. | Revolving North American credit facility
Long-term debt
Debt instrument		11.1
WCS
Long-term debt
Financing capital lease	68.2	68.6
WCS | Promissory Notes
Long-term debt
Debt instrument	2.4	2.4
Tremont | Promissory Notes
Long-term debt
Debt instrument	17.4	19.1
BMI | Bank note payable
Long-term debt
Debt instrument	10.9	11.2
LandWell | Note payable to the City of Henderson
Long-term debt
Debt instrument	$ 3.1	$ 3.1