Accounts Payable and Accrued Liabilities - Schedule of Accounts Payable and Accrued Liabilities (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Payable to affiliates:
Employee benefits	$ 25.1	$ 29.2
Deferred income	28.9	32.0
Accrued sales discounts and rebates	19.2	22.6
Environmental remediation and related costs	14.7	15.3
Reserve for uncertain tax positions	3.3	3.3
Accrued workforce reduction costs	0.2	1.2
Other	40.5	28.8
Total	302.8	281.2
Kronos Worldwide, Inc.
Accounts payable:
Accounts payable	101.5	84.9
CompX
Accounts payable:
Accounts payable	3.7	2.6
WCS
Accounts payable:
Accounts payable	1.5	1.6
BMI and LandWell
Accounts payable:
Accounts payable	2.5	2.2
NL
Accounts payable:
Accounts payable	1.3	2.4
Other
Accounts payable:
Accounts payable	0.5	0.7
Contran | Trade Accounts Payables
Payable to affiliates:
Payable to affiliates	32.5	31.4
Contran | Income Taxes Payables
Payable to affiliates:
Payable to affiliates	11.1	5.5
LPC | Trade Accounts Payables
Payable to affiliates:
Payable to affiliates	14.1	14.7
Interest Rate Swap
Payable to affiliates:
Hedging liabilities	$ 2.2	$ 2.8