Investment in Kronos Worldwide, Inc. - Selected Financial Information of Kronos Balance Sheet (Detail) - Kronos - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Schedule Of Equity Method Investments [Line Items]
Current assets	$ 710.8	$ 879.9
Property and equipment, net	429.5	479.7
Investment in TiO2 joint venture	82.9	89.0
Other noncurrent assets	19.5	184.5
Total assets	1,242.7	1,633.1
Current liabilities	201.7	234.2
Long-term debt	337.2	339.7
Accrued pension and postretirement benefits	209.4	245.2
Other noncurrent liabilities	32.5	32.9
Stockholders' equity	461.9	781.1
Total liabilities and stockholders' equity	$ 1,242.7	$ 1,633.1