Accounts and other receivables, net - Components of Accounts and Other Receivables (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Trade accounts receivable:
VAT and other receivables	$ 43.1	$ 42.2
Refundable income taxes	10.9	18.3
Receivable from affiliates: LPC	35.4
Receivable from affiliates: Contran - income taxes, net	1.2	0.3
Allowance for doubtful accounts	(1.4)	(1.5)
Total	411.2	302.5
Kronos Worldwide, Inc. [Member]
Trade accounts receivable:
Accounts receivable	303.9	229.7
CompX [Member]
Trade accounts receivable:
Accounts receivable	9.7	8.7
WCS [Member]
Trade accounts receivable:
Accounts receivable	$ 8.4	$ 4.8