Derivative Instruments (Schedule Of Average Notional Value By Sector Of Futures And Forward Currency Contracts) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Long Positions [Member]
Derivative [Line Items]
Average notional amount of futures and forward currency contracts	$ 209,610,182	$ 358,738,846
Long Positions [Member] | Futures Contracts [Member]
Derivative [Line Items]
Average notional amount of futures and forward currency contracts	193,725,289	336,581,353
Long Positions [Member] | Energies [Member]
Derivative [Line Items]
Average notional amount of futures and forward currency contracts	13,493,572	8,306,253
Long Positions [Member] | Grains [Member]
Derivative [Line Items]
Average notional amount of futures and forward currency contracts	1,962,864	3,417,256
Long Positions [Member] | Interest Rates [Member]
Derivative [Line Items]
Average notional amount of futures and forward currency contracts	100,109,094	271,415,198
Long Positions [Member] | Livestock [Member]
Derivative [Line Items]
Average notional amount of futures and forward currency contracts	180,225	510,300
Long Positions [Member] | Metals [Member]
Derivative [Line Items]
Average notional amount of futures and forward currency contracts	14,629,243	547,550
Long Positions [Member] | Softs [Member]
Derivative [Line Items]
Average notional amount of futures and forward currency contracts	833,210	372,238
Long Positions [Member] | Stock Indices [Member]
Derivative [Line Items]
Average notional amount of futures and forward currency contracts	62,517,081	52,012,558
Long Positions [Member] | Forward Currency Contracts [Member]
Derivative [Line Items]
Average notional amount of futures and forward currency contracts	15,884,893	22,157,493
Short Positions [Member]
Derivative [Line Items]
Average notional amount of futures and forward currency contracts	184,326,596	275,601,512
Short Positions [Member] | Futures Contracts [Member]
Derivative [Line Items]
Average notional amount of futures and forward currency contracts	143,524,210	192,653,448
Short Positions [Member] | Energies [Member]
Derivative [Line Items]
Average notional amount of futures and forward currency contracts	8,451,385	23,567,196
Short Positions [Member] | Grains [Member]
Derivative [Line Items]
Average notional amount of futures and forward currency contracts	5,938,694	9,120,410
Short Positions [Member] | Interest Rates [Member]
Derivative [Line Items]
Average notional amount of futures and forward currency contracts	108,167,176	97,171,043
Short Positions [Member] | Livestock [Member]
Derivative [Line Items]
Average notional amount of futures and forward currency contracts		408,595
Short Positions [Member] | Metals [Member]
Derivative [Line Items]
Average notional amount of futures and forward currency contracts	3,487,808	13,668,889
Short Positions [Member] | Softs [Member]
Derivative [Line Items]
Average notional amount of futures and forward currency contracts	1,695,831	3,255,267
Short Positions [Member] | Stock Indices [Member]
Derivative [Line Items]
Average notional amount of futures and forward currency contracts	15,783,316	45,462,048
Short Positions [Member] | Forward Currency Contracts [Member]
Derivative [Line Items]
Average notional amount of futures and forward currency contracts	$ 40,802,386	$ 82,948,064