CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Net sales	$ 108,920	$ 108,994	$ 103,846
Cost of sales	73,753	75,593	71,598
Gross margin	35,167	33,401	32,248
Selling, general and administrative expense	19,593	19,430	18,641
Other operating income (expense):
Insurance recoveries	443	3,657	10,368
Other income, net	9	120	186
Corporate expense	(17,009)	(17,480)	(21,323)
Income (loss) from operations	(983)	268	2,838
Equity in earnings (losses) of Kronos Worldwide, Inc.	13,171	(52,770)	30,161
Other income (expense):
Securities transactions, net		3	16
Interest and dividends	1,732	1,172	1,618
Interest expense	(4)
Income (loss) before taxes	13,916	(51,327)	34,633
Income tax expense (benefit)	(2,777)	(28,611)	5,003
Net income (loss)	16,693	(22,716)	29,630
Noncontrolling interest in net income of subsidiary	1,368	1,193	1,131
Net income (loss) attributable to NL stockholders	$ 15,325	$ (23,909)	$ 28,499
Amounts attributable to NL stockholders:
Basic and diluted net income (loss) per share	$ 0.31	$ (0.49)	$ 0.59
Weighted average shares used in the calculation of net income (loss) per share	48,701	48,688	48,679