Schedule of Investments (Unaudited) - Futures Contracts		6 Months Ended	12 Months Ended
		Jun. 30, 2018 USD ($) Contract	Dec. 31, 2017 USD ($) Contract
Schedule of Investments [Line Items]
Value		$ 3,008,988,691	$ 2,156,785,955
Futures [Member] | Long [Member]
Schedule of Investments [Line Items]
Value	[1]	112,593,712	115,669,315
Unrealized Appreciation (Depreciation)	[1]	$ 112,593,712	$ 115,669,315
Futures [Member] | Long [Member] | CME SWAPS MARKETS (CBOT) [Member] | Corn [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		8,209	6,533
Expiration Date		Sep. 30, 2018	Sep. 30, 2018
Notional Value		$ 147,556,775	$ 122,412,087
Value	[1]	(14,970,297)	(7,940,794)
Unrealized Appreciation (Depreciation)	[1]	$ (14,970,297)	$ (7,940,794)
Futures [Member] | Long [Member] | CME SWAPS MARKETS (CBOT) [Member] | Soybean [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		3,132	2,491
Expiration Date		Nov. 30, 2018	Nov. 30, 2018
Notional Value		$ 137,808,000	$ 121,529,663
Value	[1]	(19,135,916)	(1,887,221)
Unrealized Appreciation (Depreciation)	[1]	$ (19,135,916)	$ (1,887,221)
Futures [Member] | Long [Member] | CME SWAPS MARKETS (CBOT) [Member] | Wheat [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		5,906	5,355
Expiration Date		Jul. 31, 2019	Jul. 31, 2018
Notional Value		$ 161,972,050	$ 121,357,688
Value	[1]	(12,160,023)	(11,431,220)
Unrealized Appreciation (Depreciation)	[1]	$ (12,160,023)	$ (11,431,220)
Futures [Member] | Long [Member] | CME SWAPS MARKETS (COMEX) [Member] | Gold [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		1,728	1,374
Expiration Date		Aug. 31, 2018	Aug. 31, 2018
Notional Value		$ 216,777,600	$ 181,835,160
Value	[1]	(5,809,357)	9,038,964
Unrealized Appreciation (Depreciation)	[1]	$ (5,809,357)	$ 9,038,964
Futures [Member] | Long [Member] | CME SWAPS MARKETS (COMEX) [Member] | Silver [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		641	509
Expiration Date		Dec. 31, 2018	Dec. 31, 2018
Notional Value		$ 52,292,780	$ 44,463,695
Value	[1]	(3,395,689)	57,475
Unrealized Appreciation (Depreciation)	[1]	$ (3,395,689)	$ 57,475
Futures [Member] | Long [Member] | ICE FUTURES EUROPE [Member] | Brent Crude Oil [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		5,708	4,539
Expiration Date		Nov. 30, 2018	Nov. 30, 2018
Notional Value		$ 443,511,600	$ 287,409,480
Value	[1]	84,614,703	14,377,382
Unrealized Appreciation (Depreciation)	[1]	$ 84,614,703	$ 14,377,382
Futures [Member] | Long [Member] | LME CLEAR [Member] | Aluminum [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		2,177	1,733
Expiration Date		Oct. 31, 2018	Oct. 31, 2018
Notional Value		$ 116,197,375	$ 99,604,175
Value	[1]	(3,222,502)	5,873,854
Unrealized Appreciation (Depreciation)	[1]	$ (3,222,502)	$ 5,873,854
Futures [Member] | Long [Member] | LME CLEAR [Member] | Copper [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		672	542
Expiration Date		Feb. 28, 2019	Feb. 28, 2018
Notional Value		$ 111,753,600	$ 98,027,475
Value	[1]	(8,692,013)	17,219,294
Unrealized Appreciation (Depreciation)	[1]	$ (8,692,013)	$ 17,219,294
Futures [Member] | Long [Member] | LME CLEAR [Member] | Zinc [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		1,481	1,177
Expiration Date		Jan. 31, 2019	Jan. 31, 2019
Notional Value		$ 104,965,875	$ 94,748,500
Value	[1]	(11,192,175)	4,384,862
Unrealized Appreciation (Depreciation)	[1]	$ (11,192,175)	$ 4,384,862
Futures [Member] | Long [Member] | ICE FUTURES U.S. [Member] | Sugar [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		9,250	7,357
Expiration Date		Sep. 30, 2018	Sep. 30, 2018
Notional Value		$ 126,910,000	$ 125,327,966
Value	[1]	(24,546,197)	(989,673)
Unrealized Appreciation (Depreciation)	[1]	$ (24,546,197)	$ (989,673)
Futures [Member] | Long [Member] | CME SWAPS MARKETS (NYMEX) [Member] | Natural Gas [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		5,343	4,163
Expiration Date		Apr. 30, 2019	Apr. 30, 2018
Notional Value		$ 140,841,480	$ 114,107,830
Value	[1]	291,331	(4,077,204)
Unrealized Appreciation (Depreciation)	[1]	$ 291,331	$ (4,077,204)
Futures [Member] | Long [Member] | CME SWAPS MARKETS (NYMEX) [Member] | NY Harbor ULSD [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		4,490	3,478
Expiration Date		May 31, 2019	May 31, 2018
Notional Value		$ 413,537,082	$ 288,967,543
Value	[1]	17,861,488	56,451,379
Unrealized Appreciation (Depreciation)	[1]	$ 17,861,488	$ 56,451,379
Futures [Member] | Long [Member] | CME SWAPS MARKETS (NYMEX) [Member] | RBOB Gasoline [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		4,757	3,785
Expiration Date		Dec. 31, 2018	Dec. 31, 2018
Notional Value		$ 393,334,448	$ 271,218,717
Value	[1]	54,244,722	9,759,527
Unrealized Appreciation (Depreciation)	[1]	$ 54,244,722	$ 9,759,527
Futures [Member] | Long [Member] | CME SWAPS MARKETS (NYMEX) [Member] | WTI Crude Oil [Member]
Schedule of Investments [Line Items]
Number of Contracts | Contract		6,618	4,819
Expiration Date		Feb. 28, 2019	Feb. 28, 2018
Notional Value		$ 447,112,080	$ 291,260,360
Value	[1]	58,705,637	24,832,690
Unrealized Appreciation (Depreciation)	[1]	$ 58,705,637	$ 24,832,690

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