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]
Currency Futures Contracts, Value		$ 33,180,899	$ 29,680,970
Short [Member] | Futures [Member] | United States of America, Dollars [Member] | ICE FUTURES U.S. [Member]
Schedule Of Investments [Line Items]
Currency Futures Contracts, Number of Contracts | Contract		348	299
Currency Futures Contracts, Expiration Date		Jun. 30, 2019	Mar. 31, 2019
Currency Futures Contracts, Notional Value		$ (33,702,060)	$ (28,624,765)
Currency Futures Contracts, Value	[1]	(229,648)	301,786
Currency Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ (229,648)	$ 301,786

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