Assets and Condensed Schedule of Investments by Class of Units - Assets by Class of Units (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Equity in brokers' trading accounts:
Cash	$ 10,866,216	$ 12,858,812
Total equity in brokers' trading accounts	14,236,389	16,478,034
Cash and cash equivalents	577,181	2,519,703
Securities owned, at fair value	50,080,807	60,736,458
Interest receivable	5,553	13,919
Total assets	64,899,930	79,748,114
Securities owned, cost (in dollars)	50,013,633	60,715,159
Class A
Equity in brokers' trading accounts:
Cash	690,592	774,851
Total equity in brokers' trading accounts	904,781	992,940
Cash and cash equivalents	36,682	151,833
Securities owned, at fair value	3,182,839	3,659,882
Interest receivable	353	839
Total assets	4,124,655	4,805,494
Securities owned, cost (in dollars)	3,178,570	3,658,597
Class A | Futures Contracts
Equity in brokers' trading accounts:
Net unrealized gain (loss) on open contracts	25,537	104,100
Class A | Forward Contracts
Equity in brokers' trading accounts:
Net unrealized gain (loss) on open contracts	(4,390)	(2,497)
Class A | Swap Contracts
Equity in brokers' trading accounts:
Net unrealized gain (loss) on open contracts	193,042	116,486
Class B
Equity in brokers' trading accounts:
Cash	7,192,106	8,461,360
Total equity in brokers' trading accounts	9,422,748	10,842,884
Cash and cash equivalents	382,023	1,658,017
Securities owned, at fair value	33,147,366	39,965,825
Interest receivable	3,676	9,159
Total assets	42,955,813	52,475,885
Securities owned, cost (in dollars)	33,102,907	39,951,813
Class B | Futures Contracts
Equity in brokers' trading accounts:
Net unrealized gain (loss) on open contracts	265,947	1,136,758
Class B | Forward Contracts
Equity in brokers' trading accounts:
Net unrealized gain (loss) on open contracts	(45,718)	(27,259)
Class B | Swap Contracts
Equity in brokers' trading accounts:
Net unrealized gain (loss) on open contracts	2,010,413	1,272,025
Legacy 1 Class
Equity in brokers' trading accounts:
Cash	71,238	166,563
Total equity in brokers' trading accounts	93,332	213,442
Cash and cash equivalents	3,784	32,638
Securities owned, at fair value	328,325	786,731
Interest receivable	36	180
Total assets	425,477	1,032,991
Securities owned, cost (in dollars)	327,886	786,455
Legacy 1 Class | Futures Contracts
Equity in brokers' trading accounts:
Net unrealized gain (loss) on open contracts	2,634	22,376
Legacy 1 Class | Forward Contracts
Equity in brokers' trading accounts:
Net unrealized gain (loss) on open contracts	(453)	(537)
Legacy 1 Class | Swap Contracts
Equity in brokers' trading accounts:
Net unrealized gain (loss) on open contracts	19,913	25,040
Legacy 2 Class
Equity in brokers' trading accounts:
Cash	56,111	53,663
Total equity in brokers' trading accounts	73,514	68,768
Cash and cash equivalents	2,980	10,515
Securities owned, at fair value	258,609	253,468
Interest receivable	29	58
Total assets	335,132	332,809
Securities owned, cost (in dollars)	258,262	253,379
Legacy 2 Class | Futures Contracts
Equity in brokers' trading accounts:
Net unrealized gain (loss) on open contracts	2,075	7,211
Legacy 2 Class | Forward Contracts
Equity in brokers' trading accounts:
Net unrealized gain (loss) on open contracts	(357)	(173)
Legacy 2 Class | Swap Contracts
Equity in brokers' trading accounts:
Net unrealized gain (loss) on open contracts	15,685	8,067
Global 1 Class
Equity in brokers' trading accounts:
Cash	2,681,756	3,178,446
Total equity in brokers' trading accounts	3,513,507	4,073,046
Cash and cash equivalents	142,447	622,821
Securities owned, at fair value	12,359,824	15,012,860
Interest receivable	1,370	3,441
Total assets	16,017,148	19,712,168
Securities owned, cost (in dollars)	12,343,245	15,007,595
Global 1 Class | Futures Contracts
Equity in brokers' trading accounts:
Net unrealized gain (loss) on open contracts	99,165	427,013
Global 1 Class | Forward Contracts
Equity in brokers' trading accounts:
Net unrealized gain (loss) on open contracts	(17,047)	(10,240)
Global 1 Class | Swap Contracts
Equity in brokers' trading accounts:
Net unrealized gain (loss) on open contracts	749,633	477,827
Global 2 Class
Equity in brokers' trading accounts:
Cash	118,828	121,251
Total equity in brokers' trading accounts	155,683	155,376
Cash and cash equivalents	6,312	23,759
Securities owned, at fair value	547,661	572,708
Interest receivable	61	131
Total assets	709,717	751,974
Securities owned, cost (in dollars)	546,925	572,506
Global 2 Class | Futures Contracts
Equity in brokers' trading accounts:
Net unrealized gain (loss) on open contracts	4,394	16,288
Global 2 Class | Forward Contracts
Equity in brokers' trading accounts:
Net unrealized gain (loss) on open contracts	(755)	(391)
Global 2 Class | Swap Contracts
Equity in brokers' trading accounts:
Net unrealized gain (loss) on open contracts	33,216	18,228
Global 3 Class
Equity in brokers' trading accounts:
Cash	55,585	102,678
Total equity in brokers' trading accounts	72,824	131,578
Cash and cash equivalents	2,953	20,120
Securities owned, at fair value	256,183	484,984
Interest receivable	28	111
Total assets	331,988	636,793
Securities owned, cost (in dollars)	255,838	484,814
Global 3 Class | Futures Contracts
Equity in brokers' trading accounts:
Net unrealized gain (loss) on open contracts	2,055	13,795
Global 3 Class | Forward Contracts
Equity in brokers' trading accounts:
Net unrealized gain (loss) on open contracts	(353)	(331)
Global 3 Class | Swap Contracts
Equity in brokers' trading accounts:
Net unrealized gain (loss) on open contracts	$ 15,537	$ 15,436