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FEES PAID BY THE FUND AND RELATED PARTY TRANSACTIONS - Additional Information (Details) - USD ($) | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Fees Paid and Related Party Transactions [Line Items] |  |  |
Percentage of Management Fee in Average Daily Total Net Assets | 0.60% |  |
Licensing fee incurred | $ 27,019 | $ 8,433 | $ 11,830
Investor tax reporting cost | 172,800 | 131,500 | 144,700
Registration fees | 124,835 | 0 | 0
Directors' fees and expenses | 17,435 | 13,028 | 13,806
USL and the Related Public Funds, other than USCI, USAG, CPER and USMI |  |  |
Fees Paid and Related Party Transactions [Line Items] |  |  |
Directors' fees and expenses | $ 585,896 | 556,951 | 521,689
On and after October 20, 2011 |  |  |
Fees Paid and Related Party Transactions [Line Items] |  |  |
Fee percentage | 0.015% |  |
USL's |  |  |
Fees Paid and Related Party Transactions [Line Items] |  |  |
Investor tax reporting cost |  | $ 13,028 | $ 13,806

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- Definition Amount of registration fee expense for issuance of shares or units. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 220 -Section 45 -Paragraph 3 -Subparagraph (m) -URI http://asc.fasb.org/extlink&oid=118262090&loc=SL114874205-224268 + Details
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- Definition Noninterest expense related to directors' fees which are fees paid by an Entity to its directors. Directors' fees may be paid in addition to salary and other benefits. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.14) -URI http://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260 + Details
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- Definition Amount of general expenses not normally included in Other Operating Costs and Expenses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.6) -URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227 + Details
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- Definition Base Fee Percentage + References No definition available. + Details
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- Definition Fees Paid and Related Party Transactions [Line Items] + References No definition available. + Details
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- Definition It represent the value of license fees and other offering expenses. + References No definition available. + Details
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- Definition Percentage of Management Fee In Average Daily Total Net Assets. + References No definition available. + Details
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