CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Net income (loss)	$ (28,900)	$ 5,806	$ (18,543)	$ 9,840
Other comprehensive income (loss), net of tax:
Marketable securities	(5,358)	(22,933)	(7,144)	(106,864)
Currency translation	1,188	(860)	(11,771)	(1,374)
Defined benefit pension plans/ Other postretirement benefit plans	(137)	(156)	(273)	(313)
Total other comprehensive loss, net	(3,220)	(23,431)	(17,367)	(107,496)
Comprehensive loss	(32,120)	(17,625)	(35,910)	(97,656)
Comprehensive income attributable to noncontrolling interest	367	334	682	613
Comprehensive loss attributable to NL stockholders	(32,487)	(17,959)	(36,592)	(98,269)
Defined Benefit Pension Plans
Other comprehensive income (loss), net of tax:
Defined benefit pension plans/ Other postretirement benefit plans	1,087	518	1,821	1,055
OPEB
Other comprehensive income (loss), net of tax:
Defined benefit pension plans/ Other postretirement benefit plans	$ (137)	$ (156)	$ (273)	$ (313)