CONSOLIDATED STATEMENTS OF STOCKHOLDERS' 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, 2018	$ 6,090	$ 301,139	$ 225,156	$ (248,270)	$ 19,443	$ 303,558
Net income			25,844		2,191	28,035
Other comprehensive income (loss), net of tax				(3,420)		(3,420)
Issuance of NL common stock	4	96				100
Dividends paid to noncontrolling interest					(470)	(470)
Other, net		(2,133)			1,543	(590)
Ending Balance at Dec. 31, 2019	6,094	299,102	251,000	(251,690)	22,707	327,213
Net income			14,680		1,423	16,103
Other comprehensive income (loss), net of tax				501		501
Issuance of NL common stock	4	96				100
Dividends paid			(7,805)			(7,805)
Dividends paid to noncontrolling interest					(676)	(676)
Other, net		(105)			18	(87)
Ending Balance at Dec. 31, 2020	6,098	299,093	257,875	(251,189)	23,472	335,349
Net income			51,188		2,172	53,360
Other comprehensive income (loss), net of tax				10,433		10,433
Issuance of NL common stock	2	99				101
Dividends paid			(11,712)			(11,712)
Dividends paid to noncontrolling interest					(1,324)	(1,324)
Other, net		583			(1,819)	(1,236)
Ending Balance at Dec. 31, 2021	$ 6,100	$ 299,775	$ 297,351	$ (240,756)	$ 22,501	$ 384,971