CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Net sales	$ 140,815	$ 114,537	$ 124,243
Cost of sales	98,066	81,689	85,280
Gross margin	42,749	32,848	38,963
Selling, general and administrative expense	22,223	21,031	21,297
Other operating income (expense):
Insurance recoveries	71	81	5,138
Other income, net	29	18	7,444
Litigation settlement expense, net			(19,266)
Corporate expense	(10,135)	(9,559)	(12,591)
Income (loss) from operations	10,491	2,357	(1,609)
Equity in earnings of Kronos Worldwide, Inc.	34,323	19,437	26,470
Other income (expense):
Interest and dividend income	1,603	2,599	6,672
Marketable equity securities	16,229	(8,671)	(863)
Other components of net periodic pension and OPEB cost	(665)	(784)	(1,375)
Interest expense	(1,142)	(1,350)	(681)
Income before income taxes	60,839	13,588	28,614
Income tax expense (benefit)	7,479	(2,515)	579
Net income	53,360	16,103	28,035
Noncontrolling interest in net income of subsidiary	2,172	1,423	2,191
Net income attributable to NL stockholders	$ 51,188	$ 14,680	$ 25,844
Amounts attributable to NL stockholders:
Net income per basic share	$ 1.05	$ 0.30	$ 0.53
Net income per diluted share	$ 1.05	$ 0.30	$ 0.53
Weighted average shares outstanding - basic	48,797	48,776	48,745
Weighted average shares outstanding - diluted	48,797	48,776	48,745