XML 73 R59.htm IDEA: XBRL DOCUMENT v3.7.0.1
Marketable Securities - Additional Information (Detail) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
3 Months Ended
Sep. 30, 2015
Dec. 31, 2016
Dec. 31, 2015
Schedule Of Available For Sale Securities [Line Items]      
Pre-tax other than temporary impairment charge to write down $ 12.0    
Valhi Inc      
Schedule Of Available For Sale Securities [Line Items]      
Pre-tax other than temporary impairment charge to write down $ 12.0    
Valhi Inc | Common stock      
Schedule Of Available For Sale Securities [Line Items]      
Investments in publicly-traded shares 1.7 1.7 1.7
Quoted market price of per share   $ 3.46 $ 1.34