Investment in Kronos Worldwide, Inc. - Selected Financial Information of Kronos Balance Sheet (Detail) - Kronos - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Schedule Of Equity Method Investments [Line Items]
Current assets	$ 650.4	$ 710.8
Property and equipment, net	434.0	429.5
Investment in TiO2 joint venture	78.9	82.9
Other noncurrent assets	16.3	19.5
Total assets	1,179.6	1,242.7
Current liabilities	182.1	201.7
Long-term debt	335.4	337.2
Accrued pension and postretirement benefits	234.2	209.4
Other noncurrent liabilities	32.9	32.5
Stockholders' equity	395.0	461.9
Total liabilities and stockholders' equity	$ 1,179.6	$ 1,242.7