Financial instruments - Additional Information (Detail)						12 Months Ended
	Dec. 31, 2012 Kronos Worldwide, Inc. [Member]	Dec. 31, 2012 Kronos International, Inc. [Member] USD ($)	Dec. 31, 2011 Kronos International, Inc. [Member] EUR (€)	Dec. 31, 2012 Senior Secured Notes [Member] Kronos Worldwide, Inc. [Member]	Dec. 31, 2011 Senior Secured Notes [Member] Kronos Worldwide, Inc. [Member]	Dec. 31, 2012 Amalgamated Sugar Company LLC [Member] USD ($)	Dec. 31, 2012 Chemicals [Member] Forward Contracts [Member] USD ($)	Dec. 31, 2011 Chemicals [Member] Forward Contracts [Member] USD ($)	Dec. 31, 2011 Chemicals [Member] Canadian Dollars [Member] Forward Contracts [Member] USD ($)	Dec. 31, 2011 Chemicals [Member] Canadian Dollars [Member] Minimum [Member] Forward Contracts [Member]	Dec. 31, 2011 Chemicals [Member] Canadian Dollars [Member] Maximum [Member] Forward Contracts [Member]	Dec. 31, 2012 Chemicals [Member] Norwegian Krone [Member] Forward Contracts [Member] USD ($)	Dec. 31, 2012 Chemicals [Member] Norwegian Krone [Member] Minimum [Member] Forward Contracts [Member]	Dec. 31, 2012 Chemicals [Member] Norwegian Krone [Member] Maximum [Member] Forward Contracts [Member]
Financial Instrument At Fair Value [Line Items]
Notional amount currency forward contract									$ 48,000,000			$ 20,000,000
Exchange floor rate										0.9969	1.0283		6.02	6.13
Maturity rate of derivative									4,000,000			5,000,000
Estimated fair value of currency forward contracts							1,800,000
Currency transaction gain							1,800,000	(800,000)
Estimated fair value of these currency forward contracts							800,000
Interest rate of note	6.50%			6.50%	6.50%
Estimated market price of the notes		1,017.5	1,004.0
Principal amount of debt instrument		1,000	1,000
Redemption price of investment						$ 250,000,000