XML 51 R21.htm IDEA: XBRL DOCUMENT
v2.4.0.8

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Additional Information) (Details) (USD $) | 9 Months Ended |  | 9 Months Ended
--- | --- | --- | ---
Sep. 30, 2013 | Feb. 29, 2012 Redemption Baskets [Member] | Feb. 29, 2012 Prior to February 29, 2012 [Member] Redemption Baskets [Member] | Sep. 30, 2013 Maximum [Member]
Significant Accounting Policies [Line Items] |  |  |  |
Minimum likelihood of tax benefits being recognized upon ultimate settlement | 50.00% |  |  |
Recognized interest income expense and penalties related to unrecognized tax benefits | $ 0 |  |  |
Number of units per basket |  | 50,000 | 100,000 |
Cash equivalents maturity period |  |  |  | 6 months

X
- Definition Cash Equivalents, Maturity Period + References No definition available. + Details
Name: | unl_CashEquivalentsMaturityPeriod
Namespace Prefix: | unl_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of Units per Basket + References No definition available. + Details
Name: | unl_NumberOfUnitsPerBasket
Namespace Prefix: | unl_
Data Type: | us-types:perUnitItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of income tax examination minimum likelihood of tax benefits being realized upon settlement. + References No definition available. + Details
Name: | unl_PercentageOfIncomeTaxExaminationMinimumLikelihoodOfTaxBenefitsBeingRealizedUponSettlement
Namespace Prefix: | unl_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Recognized interest income expense and penalties related to unrecognized tax benefits. + References No definition available. + Details
Name: | unl_RecognizedInterestIncomeExpenseAndPenaltiesRelatedToUnrecognizedTaxBenefits
Namespace Prefix: | unl_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | unl_SignificantAccountingPoliciesLineItems
Namespace Prefix: | unl_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration