XML 46 R36.htm IDEA: XBRL DOCUMENT
v3.5.0.2

Organization and Basis of Presentation - Additional Information (Detail) | Sep. 30, 2016
--- | ---
Kronos |
Organization And Basis Of Presentation [Line Items] |
Parent company ownership interest | 30.00%
Valhi Inc |
Organization And Basis Of Presentation [Line Items] |
Parent company ownership interest | 83.00%
Valhi Inc | Contran Corporation |
Organization And Basis Of Presentation [Line Items] |
Parent company ownership interest | 93.00%

X
- Definition Organization and basis of presentation. + References No definition available. + Details
Name: | nl_OrganizationAndBasisOfPresentationLineItems
Namespace Prefix: | nl_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66011266&loc=d3e33918-111571 + Details
Name: | us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The parent entity's interest in net assets of the subsidiary, expressed as a percentage. + References No definition available. + Details
Name: | us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=nl_KronosWorldwideIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=nl_ValhiIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=nl_ContranCorporationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |