Related Party Transactions - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2016	Aug. 03, 2016
Related Party Transaction [Line Items]
Note receivable from affiliate	$ 10,700,000
Unsecured Revolving Promissory Note Receivable | Valhi Inc | CompX
Related Party Transaction [Line Items]
Maximum loan amount		$ 40,000,000
Interest rate on loans repayment		1.00%
Interest rate on loans basis	prime
Note receivable from affiliate	$ 10,700,000