Accounts and Other Receivables, Net - Components of Accounts and Other Receivables (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Trade accounts receivable:
VAT and other receivables	$ 23.0	$ 24.3
Allowance for doubtful accounts	(1.2)	(1.8)
Total	322.6	303.9
Other
Trade accounts receivable:
Receivable from affiliates	2.1	1.5
Income Taxes | Contran
Trade accounts receivable:
Receivable from affiliates	6.8	9.2
Trade Accounts Receivable | Kronos Worldwide, Inc.
Trade accounts receivable:
Accounts receivable	256.5	230.9
Trade Accounts Receivable | CompX
Trade accounts receivable:
Accounts receivable	12.3	8.8
Trade Accounts Receivable | WCS
Trade accounts receivable:
Accounts receivable	10.9	7.7
Trade Accounts Receivable | BMI and LandWell
Trade accounts receivable:
Accounts receivable	0.9	1.4
Refundable Income Taxes
Trade accounts receivable:
Refundable income taxes	11.1	8.7
Trade Items | LPC
Trade accounts receivable:
Receivable from affiliates		13.0
Trade Items | Contran
Trade accounts receivable:
Receivable from affiliates	$ 0.2	$ 0.2