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, 2021	$ 6,100	$ 299,775	$ 297,351	$ (240,756)	$ 22,501	$ 384,971
Net income (loss)			39,905		2,005	41,910
Other comprehensive income (loss), net of tax				(11,030)		(11,030)
Issuance of NL common stock	1	119				120
Dividends paid			(27,336)			(27,336)
Dividends paid to noncontrolling interest					(3,916)	(3,916)
Other, net		(962)			(210)	(1,172)
Ending Balance at Sep. 30, 2022	6,101	298,932	309,920	(251,786)	20,380	383,547
Beginning Balance at Jun. 30, 2022	6,101	298,932	339,327	(246,319)	22,936	420,977
Net income (loss)			(8,904)		548	(8,356)
Other comprehensive income (loss), net of tax				(5,467)		(5,467)
Dividends paid			(20,503)			(20,503)
Dividends paid to noncontrolling interest					(3,104)	(3,104)
Ending Balance at Sep. 30, 2022	6,101	298,932	309,920	(251,786)	20,380	383,547
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