Schedule of Investments (Unaudited) - Futures Contracts		3 Months Ended	12 Months Ended
		Mar. 31, 2020 USD ($) Contract	Dec. 31, 2019 USD ($) Contract
Schedule Of Investments [Line Items]
Commodity Futures Contracts, Value		$ 98,401,167	$ 113,692,387
Futures [Member] | Long [Member]
Schedule Of Investments [Line Items]
Commodity Futures Contracts, Value	[1]	(12,253,163)	4,835,194
Commodity Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ (12,253,163)	$ 4,835,194
Futures [Member] | Long [Member] | LME Aluminum [Member]
Schedule Of Investments [Line Items]
Commodity Futures Contracts, Number of Contracts | Contract		761	870
Commodity Futures Contracts, Expiration Date		May 31, 2020	Apr. 30, 2020
Commodity Futures Contracts, Notional Value		$ 28,808,606	$ 39,465,375
Commodity Futures Contracts, Value	[1]	(3,600,182)	1,089,406
Commodity Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ (3,600,182)	$ 1,089,406
Futures [Member] | Long [Member] | LME Copper [Member]
Schedule Of Investments [Line Items]
Commodity Futures Contracts, Number of Contracts | Contract		233	267
Commodity Futures Contracts, Expiration Date		Jun. 30, 2020	Jun. 30, 2020
Commodity Futures Contracts, Notional Value		$ 28,838,119	$ 41,291,550
Commodity Futures Contracts, Value	[1]	(4,949,887)	3,022,988
Commodity Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ (4,949,887)	$ 3,022,988
Futures [Member] | Long [Member] | LME Zinc [Member]
Schedule Of Investments [Line Items]
Commodity Futures Contracts, Number of Contracts | Contract		559	638
Commodity Futures Contracts, Expiration Date		Jun. 30, 2020	Mar. 31, 2020
Commodity Futures Contracts, Notional Value		$ 26,618,881	$ 36,282,263
Commodity Futures Contracts, Value	[1]	(3,703,094)	722,800
Commodity Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ (3,703,094)	$ 722,800

[1] Unrealized Appreciation (Depreciation) and Value are presented above, net by contract.