CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Income Statement [Abstract]
Net sales	$ 27,075	$ 27,891
Cost of sales	18,870	19,325
Gross margin	8,205	8,566
Selling, general and administrative expense	4,852	4,866
Other operating income (expense):
Insurance recoveries	90	3,134
Corporate expense	(5,649)	(3,830)
Income (loss) from operations	(2,206)	3,004
Equity in earnings (losses) of Kronos Worldwide, Inc.	(1,150)	5,605
Other income - interest and dividend income	353	302
Income (loss) before income taxes	(3,003)	8,911
Income tax benefit	(822)	(1,446)
Net income (loss)	(2,181)	10,357
Noncontrolling interest in net income of subsidiary	288	315
Net income (loss) attributable to NL stockholders	$ (2,469)	$ 10,042
Amounts attributable to NL stockholders:
Basic and diluted net income (loss) per share	$ (0.05)	$ 0.21
Weighted average shares used in the calculation of net income (loss) per share	48,692	48,683