XML 45 R30.htm IDEA: XBRL DOCUMENT
v3.21.1

FINANCIAL HIGHLIGHTS (Details) - $ / shares | 3 Months Ended
--- | ---
Mar. 31, 2021 | Mar. 31, 2020
Per Share Operating Performance: |  |
Net asset value, beginning of period | $ 7.74 |
Total income (loss) | 0.17 | $ (0.78)
Total expenses | (0.02) | (0.02)
Net increase (decrease) in net asset value | 0.15 | (0.80)
Net asset value, end of period | $ 7.89 | $ 7.63
Total Return | 1.94% | (9.49%)
Ratios to Average Net Assets |  |
Total income (loss) | 1.49% | (10.16%)
Management fees | 0.75% | 0.75%
Total Expenses excluding management fees | 1.70% | 2.22%
Expense waived | (1.55%) | (2.07%)
Net expense excluding management fees | 0.15% | 0.15%
Net income (loss) | 1.27% | (10.39%)

X
- Definition Average Net Assets [Abstract] + References No definition available. + Details
Name: | unl_AverageNetAssetsAbstract
Namespace Prefix: | unl_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Expense Excluding Management Fee Percentage Net + References No definition available. + Details
Name: | unl_ExpenseExcludingManagementFeePercentageNet
Namespace Prefix: | unl_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Expenses, Excluding Management Fee Percentage + References No definition available. + Details
Name: | unl_ExpensesExcludingManagementFeePercentage
Namespace Prefix: | unl_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Increase (Decrease) In Net Asset Value Per Unit + References No definition available. + Details
Name: | unl_IncreaseDecreaseInNetAssetValuePerUnit
Namespace Prefix: | unl_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Management Incentive Fee Percentage + References No definition available. + Details
Name: | unl_ManagementIncentiveFeePercentage
Namespace Prefix: | unl_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Net asset value per unit. + References No definition available. + Details
Name: | unl_NetAssetValuePerUnit
Namespace Prefix: | unl_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of Consolidated Net Income + References No definition available. + Details
Name: | unl_PercentageOfConsolidatedNetIncome
Namespace Prefix: | unl_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of Total Revenue + References No definition available. + Details
Name: | unl_PercentageOfTotalRevenue
Namespace Prefix: | unl_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage Waiver Expense + References No definition available. + Details
Name: | unl_PercentageWaiverExpense
Namespace Prefix: | unl_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Rate Of Return On Average Asset + References No definition available. + Details
Name: | unl_RateOfReturnOnAverageAsset
Namespace Prefix: | unl_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Total Expenses, Per Unit + References No definition available. + Details
Name: | unl_TotalExpensesPerUnit
Namespace Prefix: | unl_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Total Income (Loss), Per Unit + References No definition available. + Details
Name: | unl_TotalIncomeLossPerUnit
Namespace Prefix: | unl_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_IncreaseDecreaseInPartnersCapitalRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration