Investment in Kronos Worldwide, Inc. - Selected Financial Information of Kronos Balance Sheet (Detail) - Kronos - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Schedule Of Equity Method Investments [Line Items]
Current assets	$ 1,186.9	$ 1,201.4
Property and equipment, net	465.5	486.4
Investment in TiO2 joint venture	83.1	81.3
Other noncurrent assets	149.4	129.0
Total assets	1,884.9	1,898.1
Current liabilities	227.5	233.4
Long-term debt	434.6	455.1
Accrued pension costs	249.3	262.9
Other noncurrent liabilities	126.6	106.9
Stockholders' equity	846.9	839.8
Total liabilities and stockholders' equity	$ 1,884.9	$ 1,898.1