Investment in Kronos Worldwide, Inc. - Selected Financial Information of Kronos Balance Sheet (Detail) - Kronos - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Schedule Of Equity Method Investments [Line Items]
Current assets	$ 1,219.7	$ 1,201.4
Property and equipment, net	490.6	486.4
Investment in TiO2 joint venture	90.2	81.3
Other noncurrent assets	165.3	129.0
Total assets	1,965.8	1,898.1
Current liabilities	270.6	233.4
Long-term debt	444.0	455.1
Accrued pension costs	307.4	262.9
Other noncurrent liabilities	127.7	106.9
Stockholders' equity	816.1	839.8
Total liabilities and stockholders' equity	$ 1,965.8	$ 1,898.1