Financial Instruments - Financial Instruments not Carried at Fair Value (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash, cash equivalents and restricted cash equivalents	$ 186,800,000	$ 395,900,000
Deferred payment obligation	8,200,000
Noncontrolling interest in subsidiaries	391,500,000	358,100,000
Valhi stockholders' equity, Carrying amount	601,300,000	733,600,000
Cash, cash equivalents and restricted cash equivalents, fair value	186,800,000	395,900,000
Deferred payment obligation, Fair value	8,200,000
Valhi stockholders' equity, Fair value	5,961,700,000	4,238,900,000
Kronos Worldwide, Inc.
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Noncontrolling interest in subsidiaries	241,900,000	267,000,000
Noncontrolling interest, Fair value	431,600,000	442,600,000
Kronos Worldwide, Inc. | Note Payable | Contran
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt instrument	170,000,000
Debt instrument, fair value	170,000,000
Kronos Worldwide, Inc. | Term Loan
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Loans, Carrying amount		384,500,000
Debt instrument, fair value		396,800,000
Kronos Worldwide, Inc. | Bank Credit Facility
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Variable rate credit facility, Carrying Amount	11,100,000	13,200,000
Variable rate credit facility, Fair Value	11,100,000	13,200,000
Snake River | Fixed Rate Loans
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Loans, Carrying amount	250,000,000	250,000,000
Debt instrument, fair value	250,000,000	250,000,000
WCS | Fixed Rate Loans
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Loans, Carrying amount	72,400,000	77,100,000
Debt instrument, fair value	72,400,000	77,100,000
Valhi | Credit Facility | Contran
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Variable rate credit facility, Carrying Amount	206,500,000	157,600,000
Variable rate credit facility, Fair Value	206,500,000	157,600,000
CompX
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Noncontrolling interest in subsidiaries	13,600,000	13,300,000
Noncontrolling interest, Fair value	23,100,000	23,400,000
CompX | Promissory Note
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Promissory note		18,500,000
Debt instrument, fair value		18,500,000
Tremont | Promissory Note
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt instrument	19,100,000
Debt instrument, fair value	19,100,000
BMI | Bank note payable
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt instrument	11,200,000
Debt instrument, fair value	11,200,000
Landwell | City of Henderson
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt instrument	3,100,000
Debt instrument, fair value	3,100,000
NL
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Noncontrolling interest in subsidiaries	74,500,000	77,800,000
Noncontrolling interest, Fair value	$ 92,600,000	$ 94,800,000