Investment in Kronos Worldwide, Inc. - Selected Financial Information of Kronos Income Statement (Detail) (USD $) In Thousands, unless otherwise specified	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]
Net sales	$ 24,209	$ 21,281	$ 69,701	$ 63,856
Cost of sales	16,695	14,971	48,557	45,025
Income (loss) from operations	(443)	(606)	(15,718)	(1,610)
Net income (loss)	(5,684)	10,347	(21,700)	57,839
Kronos
Schedule Of Equity Method Investments [Line Items]
Net sales	419,100	472,900	1,363,800	1,579,500
Cost of sales	371,900	386,900	1,303,100	1,068,700
Income (loss) from operations	(37,000)	38,500	(131,600)	358,500
Net income (loss)	$ (29,900)	$ 35,200	$ (104,900)	$ 236,600