CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Common stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income (loss)	Noncontrolling interest in subsidiary	Total
Beginning Balance at Dec. 31, 2020	$ 6,098	$ 299,093	$ 257,875	$ (251,189)	$ 23,472	$ 335,349
Net income (loss)			36,267		1,762	38,029
Other comprehensive income (loss), net of tax				2,316		2,316
Issuance of NL common stock	2	99				101
Dividends paid			(8,783)			(8,783)
Dividends paid to noncontrolling interest					(999)	(999)
Other, net		1,117			(1,746)	(629)
Ending Balance at Sep. 30, 2021	6,100	300,309	285,359	(248,873)	22,489	365,384
Beginning Balance at Jun. 30, 2021	6,100	300,309	277,974	(248,082)	22,274	358,575
Net income (loss)			10,313		545	10,858
Other comprehensive income (loss), net of tax				(791)		(791)
Dividends paid			(2,928)			(2,928)
Dividends paid to noncontrolling interest					(330)	(330)
Ending Balance at Sep. 30, 2021	6,100	300,309	285,359	(248,873)	22,489	365,384
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