CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Net sales	$ 108,994	$ 103,846	$ 92,045
Cost of sales	75,593	71,598	64,471
Gross margin	33,401	32,248	27,574
Selling, general and administrative expense	19,430	18,641	18,246
Other operating income (expense):
Insurance recoveries	3,657	10,368	9,427
Other income, net	120	186	29
Corporate expense	(17,480)	(21,323)	(87,042)
Income (loss) from operations	268	2,838	(68,258)
Equity in earnings (losses) of Kronos Worldwide, Inc.	(52,770)	30,161	(31,007)
Other income (expense):
Securities transactions, net	3	16	11
Interest and dividends	1,172	1,618	2,927
Interest expense			(127)
Income (loss) before taxes	(51,327)	34,633	(96,454)
Income tax expense (benefit)	(28,611)	5,003	(41,911)
Net income (loss)	(22,716)	29,630	(54,543)
Noncontrolling interest in net income of subsidiary	1,193	1,131	790
Net income (loss) attributable to NL stockholders	$ (23,909)	$ 28,499	$ (55,333)
Amounts attributable to NL stockholders:
Basic and diluted net income (loss) per share	$ (0.49)	$ 0.59	$ (1.14)
Cash dividends per share			$ 0.50
Weighted average shares used in the calculation of net income (loss) per share	48,688	48,679	48,672