Long-term debt - Revolving Credit Facility - Additional Information (Detail) (Kronos Worldwide, Inc. [Member])	12 Months Ended			12 Months Ended
	Dec. 31, 2012 North American Line of Credit [Member] USD ($)	Dec. 31, 2012 North American Line of Credit [Member] CAD	Jun. 30, 2012 North American Line of Credit [Member] USD ($)	Dec. 31, 2012 North American Line of Credit [Member] LIBOR Option [Member]	Dec. 31, 2012 North American Line of Credit [Member] Base Rate Option [Member]	Dec. 31, 2012 European Line of Credit [Member] USD ($)	Dec. 31, 2012 European Line of Credit [Member] EUR (€)	Dec. 31, 2012 Canadian Letter Of Credit Loan Agreement [Member] USD ($)	Dec. 31, 2012 Canadian Letter Of Credit Loan Agreement [Member] CAD	Dec. 31, 2011 Canadian Letter Of Credit Loan Agreement [Member] CAD	Dec. 31, 2012 Canadian Loan Agreement [Member] CAD
Line of Credit Facility [Line Items]
Borrowing availability		25,000,000	$ 125,000,000				€ 120,000,000
Credit facility maturity date	June 2017.
Availability of letters of credit	15,000,000								7,500,000
Variable rate for revolving credit facility, Minimum				1.50%	0.50%
Variable rate for revolving credit facility, Maximum				2.00%	1.00%
Fixed charge coverage ratio, minimum value	1.0
Amount available for borrowing	125,000,000					144,900,000
Credit facility borrowed and repaid	71,000,000
Average interest rate	3.75%					2.01%	2.01%
Debt instrument basis spread on variable rate						1.90%	1.90%
Borrowings under credit facility						107,400,000	80,000,000
Average interest rate on revolving bank credit facility						1.88%	1.88%
Credit facility repaid an aggregate						88,600,000	70,000,000
Principal amount of debt instrument										10,000,000	7,100,000
Restricted Deposits								7,500,000
Additional indebtedness									35,000,000