Derivative Instruments - Fair Value of Derivative Instruments (Detail) - Commodity Futures Contract [Member] - Not Designated as Hedging Instrument [Member] - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Derivatives Fair Value [Line Items]
Assets	$ 272,634	$ 14,607,615
Liabilities	$ (3,086,169)

Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4D
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
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-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624163-113959

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 20
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-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226000-175313

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant