Marketable Securities - Additional Information (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2012	Dec. 31, 2011
Valhi Common Stock [Member]
Schedule of Equity Method Investments [Line Items]
Outstanding common stock, shares	14.4	14.4
Common stock quoted market price per share	$ 12.20	$ 20.16
Stock split ratio, numerator	3
TIMET Common Stock [Member]
Schedule of Equity Method Investments [Line Items]
Outstanding common stock, shares	1.4	1.4
Common stock quoted market price per share	$ 12.83	$ 14.98