Investment in Kronos Worldwide, Inc. - Selected Financial Information of Kronos Balance Sheet (Detail) - Kronos - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Schedule Of Equity Method Investments [Line Items]
Current assets	$ 695.2	$ 710.8
Property and equipment, net	441.3	429.5
Investment in TiO2 joint venture	83.7	82.9
Other noncurrent assets	21.0	19.5
Total assets	1,241.2	1,242.7
Current liabilities	188.9	201.7
Long-term debt	346.1	337.2
Accrued pension and postretirement benefits	213.7	209.4
Other noncurrent liabilities	37.7	32.5
Stockholders' equity	454.8	461.9
Total liabilities and stockholders' equity	$ 1,241.2	$ 1,242.7