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Condensed Schedule of Investments (Parenthetical)	3 Months Ended
	Mar. 31, 2018 USD ($)
Collateral Amount On Open Futures Contracts	$ 64,518,650
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.22%, 4/12/2018 [Member]
Interest rate	1.22%
Expiration date	4/12/2018
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.23%, 4/19/2018 [Member]
Interest rate	1.23%
Expiration date	4/19/2018
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.25%, 4/26/2018 [Member]
Interest rate	1.25%
Expiration date	4/26/2018
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.27%, 5/03/2018 [Member]
Interest rate	1.27%
Expiration date	5/03/2018
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.32%, 5/10/2018 [Member]
Interest rate	1.32%
Expiration date	5/10/2018
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.37%, 5/17/2018 [Member]
Interest rate	1.37%
Expiration date	5/17/2018
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.43%, 5/24/2018 [Member]
Interest rate	1.43%
Expiration date	5/24/2018
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.43%, 5/31/2018 [Member]
Interest rate	1.43%
Expiration date	5/31/2018
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.45%, 6/07/2018 [Member]
Interest rate	1.45%
Expiration date	6/07/2018
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.46%, 6/14/2018 [Member]
Interest rate	1.46%
Expiration date	6/14/2018
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.49%, 6/21/2018 [Member]
Interest rate	1.49%
Expiration date	6/21/2018
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.50%, 6/28/2018 [Member]
Interest rate	1.50%
Expiration date	6/28/2018
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.56%, 7/05/2018 [Member]
Interest rate	1.56%
Expiration date	7/05/2018
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.56%, 7/12/2018 [Member]
Interest rate	1.56%
Expiration date	7/12/2018
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.77%, 8/16/2018 [Member]
Interest rate	1.77%
Expiration date	8/16/2018
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.82%, 8/23/2018 [Member]
Interest rate	1.82%
Expiration date	8/23/2018
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.85%, 9/06/2018 [Member]
Interest rate	1.85%
Expiration date	9/06/2018
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills 1.90%, 9/27/2018 [Member]
Interest rate	1.90%
Expiration date	9/27/2018

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No definition available.

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X

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
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The list of dates or date range within which the options may be exercised of the investment subject to option.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 6
-Subparagraph (SX 210.12-14.4(b))
-URI http://asc.fasb.org/extlink&oid=50485924&loc=d3e611322-123010

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Topic 946
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-Section S99
-Paragraph 5
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