XML 33 R33.htm IDEA: XBRL DOCUMENT v3.20.1
Related Party Transactions - Additional Information (Detail) - USD ($)
1 Months Ended 3 Months Ended
Apr. 02, 2020
Aug. 31, 2016
Mar. 31, 2020
Mar. 31, 2019
Dec. 31, 2019
Related Party Transaction [Line Items]          
Note receivable from affiliate     $ 25,500,000   $ 28,100,000
Amount loaned     15,628,000 $ 17,400,000  
NL Industries          
Related Party Transaction [Line Items]          
Cash payment to NL in lieu of state tax     900,000    
Unsecured Revolving Demand Promissory | Valhi Inc          
Related Party Transaction [Line Items]          
Maximum loan amount   $ 40,000,000      
Interest rate on loans repayment   1.00%      
Principal due on demand effective date   Dec. 31, 2021      
Note receivable from affiliate     25,500,000    
Interest income including unused commitment fees on our loan     $ 400,000 $ 600,000  
Unsecured Revolving Demand Promissory | Valhi Inc | Subsequent Event          
Related Party Transaction [Line Items]          
Note receivable from affiliate $ 30,500,000        
Amount loaned $ 5,000,000