Investment in Kronos Worldwide, Inc. - Selected Financial Information of Kronos Balance Sheet (Detail) - Kronos - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Schedule Of Equity Method Investments [Line Items]
Current assets	$ 1,163.4	$ 1,219.7
Property and equipment, net	459.0	490.6
Investment in TiO2 joint venture	92.4	90.2
Other noncurrent assets	160.0	165.3
Total assets	1,874.8	1,965.8
Current liabilities	231.2	270.6
Long-term debt	436.3	444.0
Accrued pension costs	301.4	307.4
Other noncurrent liabilities	123.6	127.7
Stockholders' equity	782.3	816.1
Total liabilities and stockholders' equity	$ 1,874.8	$ 1,965.8