Accounts and Other Receivables, Net - Components of Accounts and Other Receivables (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Trade accounts receivable:
VAT and other receivables	$ 32.7	$ 20.7
Allowance for doubtful accounts	(1.3)	(1.5)
Total	318.4	332.7
Trade Accounts Receivable | Kronos Worldwide, Inc.
Trade accounts receivable:
Accounts receivable	273.3	301.4
Trade Accounts Receivable | CompX
Trade accounts receivable:
Accounts receivable	12.2	10.5
Trade Accounts Receivable | BMI and LandWell
Trade accounts receivable:
Accounts receivable	$ 1.5	$ 1.6