CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Net income (loss)	$ 7,760	$ 1,237	$ 6,744	$ (17,306)
Other comprehensive income (loss), net of tax:
Marketable securities	6,983	(34,513)	9,182	(41,657)
Currency translation	1,777	(3,538)	3,628	(15,309)
Interest rate swap	145	(733)	(583)	(733)
Total other comprehensive income (loss), net	9,590	(38,019)	14,278	(55,386)
Comprehensive income (loss)	17,350	(36,782)	21,022	(72,692)
Comprehensive income attributable to noncontrolling interest	388	294	996	976
Comprehensive income (loss) attributable to NL stockholders	16,962	(37,076)	20,026	(73,668)
Defined Benefit Pension Plans
Other comprehensive income (loss), net of tax:
Defined benefit pension plans/ Other postretirement benefit plans	817	902	2,447	2,723
OPEB
Other comprehensive income (loss), net of tax:
Defined benefit pension plans/ Other postretirement benefit plans	$ (132)	$ (137)	$ (396)	$ (410)