Organization and Basis of Presentation - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2022 $ / shares
Basis Of Presentation And Significant Accounting Policies [Line Items]
Special cash dividends per share	$ 1.75
NL Industries | CompX International Inc
Basis Of Presentation And Significant Accounting Policies [Line Items]
Percentage of ownership held by parent company	87.00%
Valhi Inc | NL Industries
Basis Of Presentation And Significant Accounting Policies [Line Items]
Percentage of ownership held by parent company	83.00%
Contran Corporation | Valhi Inc
Basis Of Presentation And Significant Accounting Policies [Line Items]
Percentage of ownership held by parent company	92.00%