Investment in Kronos Worldwide, Inc. - Selected Financial Information of Kronos Balance Sheet (Detail) - Kronos - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Schedule Of Equity Method Investments [Line Items]
Current assets	$ 1,230.3	$ 1,201.4
Property and equipment, net	487.1	486.4
Investment in TiO2 joint venture	85.7	81.3
Other noncurrent assets	155.5	129.0
Total assets	1,958.6	1,898.1
Current liabilities	249.1	233.4
Long-term debt	452.2	455.1
Accrued pension costs	259.8	262.9
Other noncurrent liabilities	129.5	106.9
Stockholders' equity	868.0	839.8
Total liabilities and stockholders' equity	$ 1,958.6	$ 1,898.1