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		$ 24,390,359	$ 23,907,660
Futures [Member]
Schedule Of Investments [Line Items]
Currency Futures Contracts, Value	[1]	(65,397)	(638,173)
Currency Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	(65,397)	(638,173)
Futures [Member] | Long [Member]
Schedule Of Investments [Line Items]
Currency Futures Contracts, Value	[1]	(44,854)	(334,227)
Currency Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ (44,854)	$ (334,227)
Futures [Member] | Long [Member] | Canadian, Dollars [Member]
Schedule Of Investments [Line Items]
Currency Futures Contracts, Number of Contracts | Contract		109	107
Currency Futures Contracts, Expiration Date		Jun. 30, 2019	Mar. 31, 2019
Currency Futures Contracts, Notional Value		$ 8,178,270	$ 7,865,570
Currency Futures Contracts, Value	[1]	(14,544)	(157,225)
Currency Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ (14,544)	$ (157,225)
Futures [Member] | Long [Member] | New Zealand, Dollars [Member]
Schedule Of Investments [Line Items]
Currency Futures Contracts, Number of Contracts | Contract		119
Currency Futures Contracts, Expiration Date		Jun. 30, 2019
Currency Futures Contracts, Notional Value		$ 8,114,610
Currency Futures Contracts, Value	[1]	(30,310)
Currency Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	(30,310)
Futures [Member] | Long [Member] | Australia, Dollars [Member]
Schedule Of Investments [Line Items]
Currency Futures Contracts, Number of Contracts | Contract			112
Currency Futures Contracts, Expiration Date			Mar. 31, 2019
Currency Futures Contracts, Notional Value			$ 7,898,240
Currency Futures Contracts, Value	[1]		(177,002)
Currency Futures Contracts, Unrealized Appreciation (Depreciation)	[1]		(177,002)
Futures [Member] | Short [Member]
Schedule Of Investments [Line Items]
Currency Futures Contracts, Value	[1]	(20,543)	(303,946)
Currency Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ (20,543)	$ (303,946)
Futures [Member] | Short [Member] | Euro Member Countries, Euro [Member]
Schedule Of Investments [Line Items]
Currency Futures Contracts, Number of Contracts | Contract		57	57
Currency Futures Contracts, Expiration Date		Jun. 30, 2019	Mar. 31, 2019
Currency Futures Contracts, Notional Value		$ (8,043,056)	$ (8,209,781)
Currency Futures Contracts, Value	[1]	78,050	(68,337)
Currency Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ 78,050	$ (68,337)
Futures [Member] | Short [Member] | Japanses, Yen [Member]
Schedule Of Investments [Line Items]
Currency Futures Contracts, Number of Contracts | Contract		72
Currency Futures Contracts, Expiration Date		Jun. 30, 2019
Currency Futures Contracts, Notional Value		$ (8,170,650)
Currency Futures Contracts, Value	[1]	(48,773)
Currency Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ (48,773)
Futures [Member] | Short [Member] | Switzerland, Francs [Member]
Schedule Of Investments [Line Items]
Currency Futures Contracts, Number of Contracts | Contract		65	64
Currency Futures Contracts, Expiration Date		Jun. 30, 2019	Mar. 31, 2019
Currency Futures Contracts, Notional Value		$ (8,217,625)	$ (8,195,200)
Currency Futures Contracts, Value	[1]	(49,820)	(85,850)
Currency Futures Contracts, Unrealized Appreciation (Depreciation)	[1]	$ (49,820)	$ (85,850)
Futures [Member] | Short [Member] | Swedish, Krona [Member]
Schedule Of Investments [Line Items]
Currency Futures Contracts, Number of Contracts | Contract			36
Currency Futures Contracts, Expiration Date			Mar. 31, 2019
Currency Futures Contracts, Notional Value			$ (8,155,440)
Currency Futures Contracts, Value	[1]		(149,759)
Currency Futures Contracts, Unrealized Appreciation (Depreciation)	[1]		$ (149,759)

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