CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
CONSOLIDATED STATEMENTS OF OPERATIONS
Net sales	$ 161,287	$ 166,562	$ 140,815
Cost of sales	112,068	117,763	98,066
Gross margin	49,219	48,799	42,749
Selling, general and administrative expense	23,784	23,363	22,223
Other operating income (expense):
Corporate expense	11,306	11,705	10,035
Income from operations	14,129	13,731	10,491
Equity in earnings (losses) of Kronos Worldwide, Inc.	(15,003)	31,873	34,323
Other income (expense):
Interest and dividend income	9,636	3,797	1,603
Marketable equity securities	(8,156)	(8,085)	16,229
Loss on pension plan termination	4,911
Other components of net periodic pension and OPEB cost	(1,368)	(1,134)	(665)
Interest expense	(746)	(941)	(1,142)
Income (loss) before income taxes	(6,419)	39,241	60,839
Income tax expense (benefit)	(7,001)	2,785	7,479
Net income	582	36,456	53,360
Noncontrolling interest in net income of subsidiary	2,890	2,612	2,172
Net income (loss) attributable to NL stockholders	$ (2,308)	$ 33,844	$ 51,188
Amounts attributable to NL stockholders:
Net income (loss) per basic share	$ (0.05)	$ 0.69	$ 1.05
Net income (loss) per diluted share	$ (0.05)	$ 0.69	$ 1.05
Weighted average shares outstanding - basic	48,827	48,811	48,797
Weighted average shares outstanding - diluted	48,827	48,811	48,797