Investment in Kronos Worldwide, Inc. - Selected Financial Information of Kronos Balance Sheet (Detail) - Kronos - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Schedule Of Equity Method Investments [Line Items]
Current assets	$ 734.3	$ 650.4
Property and equipment, net	439.3	434.0
Investment in TiO2 joint venture	82.0	78.9
Other noncurrent assets	13.4	16.3
Total assets	1,269.0	1,179.6
Current liabilities	205.5	182.1
Long-term debt	360.9	335.4
Accrued pension and postretirement benefits	238.9	234.2
Other noncurrent liabilities	36.9	32.9
Stockholders' equity	426.8	395.0
Total liabilities and stockholders' equity	$ 1,269.0	$ 1,179.6