Investment in Kronos Worldwide, Inc. - Changes in Carrying Value of Investment (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Schedule Of Equity Method Investments [Line Items]
Balance at the beginning of the period			$ 323,128,000
Equity in loss of Kronos	9,101,000	(10,715,000)	31,891,000	(71,951,000)
Dividends received from Kronos			(15,849,000)	(15,849,000)
Balance at the end of the period	280,100,000		280,100,000
Investment in Kronos Worldwide, Inc.
Schedule Of Equity Method Investments [Line Items]
Balance at the beginning of the period			323,100,000
Equity in loss of Kronos			(31,900,000)
Dividends received from Kronos			(15,800,000)
Other, principally equity in Kronos’ other comprehensive income			4,700,000
Balance at the end of the period	$ 280,100,000		$ 280,100,000