Accounts and Other Receivables, Net - Components of Accounts and Other Receivables (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Trade accounts receivable:
VAT and other receivables	$ 26.6	$ 20.7
Insurance recovery receivable	15.0
Refundable income taxes	0.7	0.5
Allowance for doubtful accounts	(1.4)	(1.5)
Total	411.6	365.8
NL
Trade accounts receivable:
Insurance recovery receivable	15.0
Trade Accounts Receivable | Kronos Worldwide, Inc.
Trade accounts receivable:
Accounts receivable	350.8	301.4
Trade Accounts Receivable | CompX
Trade accounts receivable:
Accounts receivable	13.8	10.5
Trade Accounts Receivable | BMI and LandWell
Trade accounts receivable:
Accounts receivable	1.9	1.6
Contran | Trade Items
Trade accounts receivable:
Receivable from affiliates	0.9	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