Related party transactions - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
LPC [Member]
Related Party Transaction [Line Items]
Purchase of Ti02 from LPC	$ 250,200,000	$ 144,800,000	$ 133,700,000
Sales of feedstock ore to LPC	143,700,000	93,000,000	5,200,000
Note Payable TFMC [Member] | CompX [Member]
Related Party Transaction [Line Items]
Interest expense	300,000	500,000	600,000
Financial Assurance to Texas Government Agencies [Member] | Additional Collateral Trust [Member] | WCS [Member]
Related Party Transaction [Line Items]
Marketable securities released	122,400,000
Contran [Member] | Unsecured Revolving Demand Note Receivable [Member]
Related Party Transaction [Line Items]
Unsecured Revolving Demand Promissory note		65,000,000
Interest at prime plus rate	6.25%	3.00%
Debt due date, start date	Dec. 31, 2013	Dec. 31, 2013
Loans outstanding to Contran		11,200,000
Promissory note received from sale of portion of excess insurance reserve to BMI	52,800,000
Loan repayment received	64,000,000
Contran [Member] | Revolving credit facility [Member]
Related Party Transaction [Line Items]
Interest expense	100,000	500,000	3,900,000
Contran [Member] | Performance Guarantee [Member] | WCS [Member]
Related Party Transaction [Line Items]
Decommissioning obligations	5,500,000	5,500,000	5,500,000
Contran [Member] | Performance Guarantee [Member] | Collateral [Member] | LLRW Disposal Facility [Member]
Related Party Transaction [Line Items]
Marketable securities as collateral		49,200,000
Collateral pledge fee	700,000	100,000
Pledged marketable securities released on	Nov. 30, 2016
Contran [Member] | Performance Guarantee [Member] | Letter of credit [Member] | WCS [Member]
Related Party Transaction [Line Items]
Related Party Transaction	100,000	100,000	100,000
Decommissioning obligations	5,900,000	5,900,000	5,900,000
Contran [Member] | Financial Assurance to Texas Government Agencies [Member] | Surety Bond [Member] | VALHI, INC. [Member] | WCS [Member]
Related Party Transaction [Line Items]
Debt guaranteed		20,000,000
Contran [Member] | Interest Income [Member] | Unsecured Revolving Demand Note Receivable [Member]
Related Party Transaction [Line Items]
Interest income	800,000	36,000
Contran [Member] | Intercorporate Services Agreements Fees [Member]
Related Party Transaction [Line Items]
Related Party Transaction	32,000,000	27,100,000	25,100,000
Contran [Member] | Intercorporate Services Agreements Fees [Member] | Scenario, Forecast [Member]
Related Party Transaction [Line Items]
Related Party Transaction	36,100,000
Utility Services Fee [Member] | BMI [Member] | TIMET [Member]
Related Party Transaction [Line Items]
Related Party Transaction	1,800,000	1,600,000	1,400,000
TIMET [Member] | BMI [Member] | Sale Of Insurance Coverage [Member]
Related Party Transaction [Line Items]
Interest income		2,800,000
Promissory note received from sale of portion of excess insurance reserve to BMI		1,400,000
Promissory note bears interest rate		3.00%
TIMET [Member] | BMI [Member] | Cash [Member] | Sale Of Insurance Coverage [Member]
Related Party Transaction [Line Items]
Interest income		$ 1,400,000