CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Net income	$ 10,347	$ 27,815	$ 57,839	$ 62,632
Other comprehensive income (loss), net of tax:
Currency translation adjustment	8,405	(6,226)	4,015	(3,031)
Marketable securities adjustment	(482)	9,334	(79,099)	98,116
Total other comprehensive income (loss)	8,341	3,409	(73,811)	95,999
Comprehensive income (loss)	18,688	31,224	(15,972)	158,631
Comprehensive income (loss) attributable to noncontrolling interest	(459)	130	(945)	(667)
Comprehensive income (loss) attributable to NL stockholders	18,229	31,354	(16,917)	157,964
Pension plans [Member]
Other comprehensive income (loss), net of tax:
Benefit plans	556	448	1,687	1,354
OPEB plan [Member]
Other comprehensive income (loss), net of tax:
Benefit plans	$ (138)	$ (147)	$ (414)	$ (440)

The change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to the reporting entity. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, but excludes any and all transactions which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.

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The change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to noncontrolling interests. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.

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- Definition

The change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to the economic entity, including both controlling (parent) and noncontrolling interests. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, including any and all transactions which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.

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- Definition

Amount after tax, before reclassification adjustments, resulting from the process of expressing in the reporting currency of the reporting entity those amounts that are denominated or measured in a different currency, and from transactions whose terms are denominated in a currency other than the entity's functional currency.

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- Definition

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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