XML 95 R66.htm IDEA: XBRL DOCUMENT v2.4.1.9
Long-Term Debt - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
6 Months Ended 12 Months Ended
Jun. 30, 2010
Dec. 31, 2014
Jan. 30, 2010
Dec. 31, 2013
Debt Instrument [Line Items]        
Borrowing under credit facility     $ 40us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity  
NL        
Debt Instrument [Line Items]        
Borrowing under credit facility       40us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ dei_LegalEntityAxis
= nl_NlMember
Debt Instrument, Interest Rate Terms   Our borrowings from Valhi under this revolving note are unsecured bear interest at prime rate plus 2.75%    
Debt instrument interest rate 2.75%us-gaap_RelatedPartyTransactionRate
/ dei_LegalEntityAxis
= nl_NlMember
     
Outstanding borrowings   $ 0us-gaap_LineOfCredit
/ dei_LegalEntityAxis
= nl_NlMember
  $ 0us-gaap_LineOfCredit
/ dei_LegalEntityAxis
= nl_NlMember