CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
CONDENSED CONSOLIDATED STATEMENTS OF INCOME
Net sales	$ 166,562	$ 140,815	$ 114,537
Cost of sales	117,763	98,066	81,689
Gross margin	48,799	42,749	32,848
Selling, general and administrative expense	23,363	22,223	21,031
Other operating income (expense):
Corporate expense	11,705	10,035	9,460
Income from operations	13,731	10,491	2,357
Equity in earnings of Kronos Worldwide, Inc.	31,873	34,323	19,437
Other income (expense):
Interest and dividend income	3,797	1,603	2,599
Marketable equity securities	(8,085)	16,229	(8,671)
Other components of net periodic pension and OPEB cost	(1,134)	(665)	(784)
Interest expense	(941)	(1,142)	(1,350)
Income before income taxes	39,241	60,839	13,588
Income tax expense (benefit)	2,785	7,479	(2,515)
Net income	36,456	53,360	16,103
Noncontrolling interest in net income of subsidiary	2,612	2,172	1,423
Net income attributable to NL stockholders	$ 33,844	$ 51,188	$ 14,680
Amounts attributable to NL stockholders:
Net income (loss) per basic share	$ 0.69	$ 1.05	$ 0.30
Net income (loss) per diluted share	$ 0.69	$ 1.05	$ 0.30
Weighted average shares outstanding - basic	48,811	48,797	48,776
Weighted average shares outstanding - diluted	48,811	48,797	48,776