Investment in Kronos Worldwide, Inc. - Selected Financial Information of Kronos Income Statement (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Schedule of Equity Method Investments [Line Items]
Net sales	$ 24,039	$ 22,147	$ 45,492	$ 42,575
Cost of sales	16,429	15,638	31,862	30,054
Income (loss) from operations	(12,422)	12,455	(15,275)	(1,004)
Net income (loss)	(14,018)	26,245	(16,016)	47,492
Kronos [Member]
Schedule of Equity Method Investments [Line Items]
Net sales	481,100	545,300	944,700	1,106,600
Cost of sales	471,500	382,000	931,200	681,800
Income (loss) from operations	(47,700)	110,600	(94,600)	320,000
Net income (loss)	$ (33,900)	$ 64,500	$ (75,000)	$ 201,400