Accounts Payable and Accrued Liabilities - Schedule of Accounts Payable and Accrued Liabilities (Detail) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Payable to affiliates:
Employee benefits	$ 35.3	$ 29.2
Deferred income	32.8	32.0
Accrued sales discounts and rebates	27.2	22.6
Environmental remediation and related costs	12.7	15.3
Reserve for uncertain tax positions		3.3
Accrued workforce reduction costs	0.2	1.2
Other	42.5	28.8
Total	327.3	281.2
Kronos Worldwide, Inc.
Accounts payable:
Accounts payable	116.8	84.9
CompX
Accounts payable:
Accounts payable	2.9	2.6
Waste Control Specialists
Accounts payable:
Accounts payable	1.8	1.6
BMI and LandWell
Accounts payable:
Accounts payable	2.3	2.2
NL
Accounts payable:
Accounts payable	2.5	2.4
Other
Accounts payable:
Accounts payable	0.3	0.7
Contran | Trade Accounts Payables
Payable to affiliates:
Payable to affiliates	37.8	31.4
Contran | Income Taxes Payables
Payable to affiliates:
Payable to affiliates		5.5
LPC | Trade Accounts Payables
Payable to affiliates:
Payable to affiliates	$ 12.2	14.7
Interest Rate Swap
Payable to affiliates:
Hedging liabilities		$ 2.8