Accounts and Other Receivables, Net - Components of Accounts and Other Receivables (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Trade accounts receivable:
VAT and other receivables	$ 27.5	$ 20.7
Insurance recovery receivable	15.0
Refundable income taxes	2.7	0.5
Allowance for doubtful accounts	(1.3)	(1.5)
Total	381.7	365.8
NL
Trade accounts receivable:
Insurance recovery receivable	15.0
Trade Accounts Receivable | Kronos Worldwide, Inc.
Trade accounts receivable:
Accounts receivable	318.5	301.4
Trade Accounts Receivable | CompX
Trade accounts receivable:
Accounts receivable	13.4	10.5
Trade Accounts Receivable | BMI and LandWell
Trade accounts receivable:
Accounts receivable	1.8	1.6
Contran | Trade Items
Trade accounts receivable:
Receivable from affiliates	0.8	1.0
Contran | Income Taxes
Trade accounts receivable:
Receivable from affiliates		19.4
LPC | Trade Items
Trade accounts receivable:
Receivable from affiliates		8.9
Other | Trade Items
Trade accounts receivable:
Receivable from affiliates	$ 3.3	$ 3.3