CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Common stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive loss	Noncontrolling interest in subsidiary	Total
Beginning Balance at Dec. 31, 2022	$ 6,101	$ 298,598	$ 300,442	$ (222,991)	$ 20,597	$ 402,747
Net income (loss)			(9,893)		2,031	(7,862)
Other comprehensive income (loss), net of tax				1,964	8	1,972
Issuance of NL common stock	2	98				100
Dividends paid			(10,254)			(10,254)
Dividends paid to noncontrolling interest					(1,167)	(1,167)
Other, net		172				172
Ending Balance at Sep. 30, 2023	6,103	298,868	280,295	(221,027)	21,469	385,708
Beginning Balance at Jun. 30, 2023	6,103	298,868	283,784	(221,098)	21,117	388,774
Net income (loss)			(69)		737	668
Other comprehensive income (loss), net of tax				71	4	75
Dividends paid			(3,420)			(3,420)
Dividends paid to noncontrolling interest					(389)	(389)
Ending Balance at Sep. 30, 2023	6,103	298,868	280,295	(221,027)	21,469	385,708
Beginning Balance at Dec. 31, 2023	6,103	298,868	284,462	(219,621)	21,950	391,762
Net income (loss)			50,684		1,458	52,142
Other comprehensive income (loss), net of tax				(1,966)		(1,966)
Issuance of NL common stock	2	98				100
Dividends paid			(32,726)			(32,726)
Dividends paid to noncontrolling interest					(4,531)	(4,531)
Other, net		133			16	149
Ending Balance at Sep. 30, 2024	6,105	299,099	302,420	(221,587)	18,893	404,930
Beginning Balance at Jun. 30, 2024	6,105	299,099	291,322	(223,434)	22,124	395,216
Net income (loss)			36,010		364	36,374
Other comprehensive income (loss), net of tax				1,847		1,847
Dividends paid			(24,912)			(24,912)
Dividends paid to noncontrolling interest					(3,595)	(3,595)
Ending Balance at Sep. 30, 2024	$ 6,105	$ 299,099	$ 302,420	$ (221,587)	$ 18,893	$ 404,930