XML 28 R24.htm IDEA: XBRL DOCUMENT
v3.3.0.814

Contracts and Agreements (Brokerage Commissions) (Details) - USD ($) | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2015 | Sep. 30, 2014 | Sep. 30, 2015 | Sep. 30, 2014
Long Duration Contracts Assumptions By Product And Guarantee [Line Items] |  |  |  |
Brokerage commissions | $ 5,205 | $ 1,076 | $ 15,370 | $ 3,592
Brokerage commissions as a percentage of average daily net assets | 0.03% | 0.01% | 0.03% | 0.01%
Rebalancing Investments Transaction [Member] |  |  |  |
Long Duration Contracts Assumptions By Product And Guarantee [Line Items] |  |  |  |
Brokerage commissions |  |  | $ 9,525 | $ 2,908
Brokerage commissions as a percentage of average daily net assets | 61.97% | 80.96% | 61.97% | 80.96%
Trades Necessitated By Creation And Redemption Activity [Member] |  |  |  |
Long Duration Contracts Assumptions By Product And Guarantee [Line Items] |  |  |  |
Brokerage commissions |  |  | $ 5,845 | $ 684
Brokerage commissions as a percentage of average daily net assets | 38.03% | 19.04% | 38.03% | 19.04%

X
- Definition The amount of expense during the period for floor brokerage fees paid to other broker-dealers to execute trades on their behalf, stock exchange fees, order flow fees, and clearance fees. + References No definition available. + Details
Name: | us-gaap_FloorBrokerageExchangeAndClearanceFees
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_LongDurationContractsAssumptionsByProductAndGuaranteeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of Average Daily Net Assets + References No definition available. + Details
Name: | usl_PercentageOfAverageDailyNetAssets
Namespace Prefix: | usl_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_NatureOfExpenseAxis=usl_RebalancingInvestmentsTransactionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_NatureOfExpenseAxis=usl_TradesNecessitatedByCreationAndRedemptionActivityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |