Accounts and Other Receivables, Net - Components of Accounts and Other Receivables (Detail) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Trade accounts receivable:
VAT and other receivables	$ 23.4	$ 20.7
Refundable income taxes	0.2	0.5
Allowance for doubtful accounts	(1.5)	(1.5)
Total	416.5	365.8
Trade Accounts Receivable | Kronos Worldwide, Inc.
Trade accounts receivable:
Accounts receivable	347.3	301.4
Trade Accounts Receivable | CompX
Trade accounts receivable:
Accounts receivable	12.7	10.5
Trade Accounts Receivable | BMI and LandWell
Trade accounts receivable:
Accounts receivable	1.0	1.6
Trade Items | Contran
Trade accounts receivable:
Receivable from affiliates	0.9	1.0
Trade Items | LPC
Trade accounts receivable:
Receivable from affiliates	9.3	8.9
Trade Items | Other
Trade accounts receivable:
Receivable from affiliates	3.5	3.3
Income Taxes | Contran
Trade accounts receivable:
Receivable from affiliates	$ 19.7	$ 19.4