Schedule of Investments (Unaudited) - Futures Contracts - Futures [Member]		6 Months Ended	12 Months Ended
		Jun. 30, 2017 USD ($) Contract	Dec. 31, 2016 USD ($) Contract
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity		(1.46%)	0.24%
Unrealized Appreciation/ (Depreciation)	[1]	$ (7,870,176)	$ 1,988,810
Notional Value		$ 539,605,755	$ 845,905,220
United States of America, Dollars | ICE FUTURES U.S. [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity		(1.46%)	0.24%
Unrealized Appreciation/ (Depreciation)	[1]	$ (7,870,176)	$ 1,988,810
Notional Value		$ 539,605,755	$ 845,905,220
Number of Contracts | Contract		5,655	8,270
Maturity Date		Sep. 18, 2017	Mar. 13, 2017

[1] Unrealized appreciation/(depreciation) is presented above, net by contract.