Schedule of Investments (Unaudited) - Futures Contracts		3 Months Ended	12 Months Ended
		Mar. 31, 2019 USD ($) Contract	Dec. 31, 2018 USD ($) Contract
Schedule of Investments [Line Items]
Commodity Futures Contracts, Value		$ 1,767,295,784	$ 2,009,510,843
Futures [Member] | Long [Member]
Schedule of Investments [Line Items]
Commodity Futures Contracts, Value	[1]	(19,827,998)	(243,800,174)
Commodity Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ (19,827,998)	$ (243,800,174)
Futures [Member] | Long [Member] | CBOT [Member] | Corn [Member]
Schedule of Investments [Line Items]
Commodity Futures Contracts, Number of Contracts | Contract		5,153	6,161
Commodity Futures Contracts, Expiration Date		Sep. 30, 2019	Sep. 30, 2019
Commodity Futures Contracts, Notional Value		$ 96,618,750	$ 121,217,675
Commodity Futures Contracts, Value	[1]	(8,065,148)	(4,115,659)
Commodity Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ (8,065,148)	$ (4,115,659)
Futures [Member] | Long [Member] | CBOT [Member] | Soybean [Member]
Schedule of Investments [Line Items]
Commodity Futures Contracts, Number of Contracts | Contract		2,218	2,652
Commodity Futures Contracts, Expiration Date		Nov. 30, 2019	Nov. 30, 2019
Commodity Futures Contracts, Notional Value		$ 101,917,100	$ 124,014,150
Commodity Futures Contracts, Value	[1]	(1,494,403)	513,337
Commodity Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ (1,494,403)	$ 513,337
Futures [Member] | Long [Member] | CBOT [Member] | Wheat [Member]
Schedule of Investments [Line Items]
Commodity Futures Contracts, Number of Contracts | Contract		3,825	4,579
Commodity Futures Contracts, Expiration Date		Jul. 31, 2019	Jul. 31, 2019
Commodity Futures Contracts, Notional Value		$ 88,644,375	$ 118,710,575
Commodity Futures Contracts, Value	[1]	(23,562,967)	(16,075,643)
Commodity Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ (23,562,967)	$ (16,075,643)
Futures [Member] | Long [Member] | CME SWAPS MARKETS (COMEX) [Member] | Gold [Member]
Schedule of Investments [Line Items]
Commodity Futures Contracts, Number of Contracts | Contract		1,158	1,425
Commodity Futures Contracts, Expiration Date		Feb. 29, 2020	Feb. 28, 2019
Commodity Futures Contracts, Notional Value		$ 153,133,920	$ 182,585,250
Commodity Futures Contracts, Value	[1]	(438,080)	4,757,025
Commodity Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ (438,080)	$ 4,757,025
Futures [Member] | Long [Member] | CME SWAPS MARKETS (COMEX) [Member] | Silver [Member]
Schedule of Investments [Line Items]
Commodity Futures Contracts, Number of Contracts | Contract		502	600
Commodity Futures Contracts, Expiration Date		May 31, 2019	May 31, 2019
Commodity Futures Contracts, Notional Value		$ 37,926,100	$ 46,878,000
Commodity Futures Contracts, Value	[1]	870,893	2,594,092
Commodity Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ 870,893	$ 2,594,092
Futures [Member] | Long [Member] | ICE FUTURES EUROPE [Member] | Brent Crude Oil [Member]
Schedule of Investments [Line Items]
Commodity Futures Contracts, Number of Contracts | Contract		3,190	3,816
Commodity Futures Contracts, Expiration Date		Nov. 30, 2019	Nov. 30, 2019
Commodity Futures Contracts, Notional Value		$ 210,412,400	$ 210,834,000
Commodity Futures Contracts, Value	[1]	(15,478,625)	(61,104,242)
Commodity Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ (15,478,625)	$ (61,104,242)
Futures [Member] | Long [Member] | LME CLEAR [Member] | Aluminum [Member]
Schedule of Investments [Line Items]
Commodity Futures Contracts, Number of Contracts | Contract		1,500	1,791
Commodity Futures Contracts, Expiration Date		Oct. 31, 2019	Oct. 31, 2019
Commodity Futures Contracts, Notional Value		$ 72,946,875	$ 85,027,725
Commodity Futures Contracts, Value	[1]	(5,122,250)	(8,383,194)
Commodity Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ (5,122,250)	$ (8,383,194)
Futures [Member] | Long [Member] | LME CLEAR [Member] | Copper [Member]
Schedule of Investments [Line Items]
Commodity Futures Contracts, Number of Contracts | Contract		496	595
Commodity Futures Contracts, Expiration Date		Sep. 30, 2019	Feb. 28, 2019
Commodity Futures Contracts, Notional Value		$ 80,438,800	$ 88,770,281
Commodity Futures Contracts, Value	[1]	6,765,750	(14,524,306)
Commodity Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ 6,765,750	$ (14,524,306)
Futures [Member] | Long [Member] | LME CLEAR [Member] | Zinc [Member]
Schedule of Investments [Line Items]
Commodity Futures Contracts, Number of Contracts | Contract		1,246	1,463
Commodity Futures Contracts, Expiration Date		Sep. 30, 2019	Mar. 31, 2019
Commodity Futures Contracts, Notional Value		$ 89,852,175	$ 90,358,537
Commodity Futures Contracts, Value	[1]	5,997,175	(4,169,375)
Commodity Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ 5,997,175	$ (4,169,375)
Futures [Member] | Long [Member] | ICE FUTURES U.S. [Member] | Sugar [Member]
Schedule of Investments [Line Items]
Commodity Futures Contracts, Number of Contracts | Contract		6,915	8,266
Commodity Futures Contracts, Expiration Date		Sep. 30, 2019	Sep. 30, 2019
Commodity Futures Contracts, Notional Value		$ 100,295,160	$ 116,001,738
Commodity Futures Contracts, Value	[1]	1,715,113	(788,761)
Commodity Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ 1,715,113	$ (788,761)
Futures [Member] | Long [Member] | CME SWAPS MARKETS (NYMEX) [Member] | Natural Gas [Member]
Schedule of Investments [Line Items]
Commodity Futures Contracts, Number of Contracts | Contract		3,726	4,463
Commodity Futures Contracts, Expiration Date		Apr. 30, 2019	Apr. 30, 2019
Commodity Futures Contracts, Notional Value		$ 99,186,120	$ 119,251,360
Commodity Futures Contracts, Value	[1]	894,927	1,564,207
Commodity Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ 894,927	$ 1,564,207
Futures [Member] | Long [Member] | CME SWAPS MARKETS (NYMEX) [Member] | NY Harbor ULSD [Member]
Schedule of Investments [Line Items]
Commodity Futures Contracts, Number of Contracts | Contract		2,546	3,046
Commodity Futures Contracts, Expiration Date		May 31, 2019	May 31, 2019
Commodity Futures Contracts, Notional Value		$ 211,169,314	$ 212,725,330
Commodity Futures Contracts, Value	[1]	(14,403,771)	(57,894,130)
Commodity Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ (14,403,771)	$ (57,894,130)
Futures [Member] | Long [Member] | CME SWAPS MARKETS (NYMEX) [Member] | RBOB Gasoline [Member]
Schedule of Investments [Line Items]
Commodity Futures Contracts, Number of Contracts | Contract		3,176	3,799
Commodity Futures Contracts, Expiration Date		Dec. 31, 2019	Dec. 31, 2019
Commodity Futures Contracts, Notional Value		$ 218,496,096	$ 212,993,974
Commodity Futures Contracts, Value	[1]	19,123,943	(26,605,722)
Commodity Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ 19,123,943	$ (26,605,722)
Futures [Member] | Long [Member] | CME SWAPS MARKETS (NYMEX) [Member] | WTI Crude Oil [Member]
Schedule of Investments [Line Items]
Commodity Futures Contracts, Number of Contracts | Contract		3,553	4,437
Commodity Futures Contracts, Expiration Date		Feb. 29, 2020	Feb. 28, 2019
Commodity Futures Contracts, Notional Value		$ 211,616,680	$ 202,859,640
Commodity Futures Contracts, Value	[1]	13,369,445	(59,567,803)
Commodity Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ 13,369,445	$ (59,567,803)

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