CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Net income (loss)	$ (5,684)	$ 10,347	$ (21,700)	$ 57,839
Other comprehensive income (loss), net of tax:
Marketable securities	59,716	(482)	71,542	(79,099)
Currency translation	4,155	8,405	(119)	4,015
Total other comprehensive income (loss)	64,419	8,341	73,069	(73,811)
Comprehensive income (loss)	58,735	18,688	51,369	(15,972)
Comprehensive income attributable to noncontrolling interest	(256)	(459)	(613)	(945)
Comprehensive income (loss) attributable to NL stockholders	58,479	18,229	50,756	(16,917)
Defined Benefit Pension Plans
Other comprehensive income (loss), net of tax:
Defined benefit pension plans/ Other postretirement benefit plans	692	556	2,078	1,687
OPEB
Other comprehensive income (loss), net of tax:
Defined benefit pension plans/ Other postretirement benefit plans	$ (144)	$ (138)	$ (432)	$ (414)