General - Statements of Income and Expenses and Changes in Members Capital (Detail) (USD $)	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012		Dec. 31, 2012
Investment income:
Interest income	$ 4,923		$ 15,545		$ 18,661		$ 26,618
Expenses:
Total expenses	1,100,504		1,571,420		2,395,891		3,295,767
Net investment income (loss)	(1,095,581)		(1,555,875)		(2,377,230)		(3,269,149)
Net gains (losses) on trading of commodity interests:
Net realized gains (losses) on closed contracts	(3,028,681)		7,293,485		(8,500,933)		25,655,440
Change in net unrealized gains (losses) on open contracts	4,010,938		(12,498,495)		184,031		(30,985,102)
Total trading results	982,257		(5,205,010)		(8,316,902)		(5,329,662)
Net income (loss)	(113,324)		(6,760,885)		(10,694,132)		(8,598,811)
Net increase (decrease) in Partners' Capital	(16,124,216)		(15,464,921)		(39,125,830)		(24,595,167)
Partners' Capital, beginning of period	119,488,435		178,874,058		142,490,049		188,004,304
Partners' Capital, end of period	103,364,219		163,409,137		103,364,219		163,409,137
Net asset value per unit (71,776.9756 and 91,670.4071 units outstanding in June 30, 2013 and 2012, respectively)	9,490.53		10,020.25		9,490.53		10,020.25
Net income (loss) per unit	$ (9.04)	[1]	$ (399.29)	[1]	$ (780.78)	[1]	$ (503.89)	[1]
Weighted average units outstanding	12,032.3498		16,854.1498		12,784.5332		17,263.4872
Limited Partners [Member]
Investment income:
Interest income	34,266		92,856		125,430		157,292
Expenses:
Clearing fees	922,068		790,621		2,040,592		1,652,070
Professional fees	120,782		74,318		210,125		177,763
Total expenses	1,042,850		864,939		2,250,717		1,829,833
Net investment income (loss)	(1,008,584)		(772,083)		(2,125,287)		(1,672,541)
Net gains (losses) on trading of commodity interests:
Net realized gains (losses) on closed contracts	(18,681,459)		39,149,093		(50,416,448)		134,716,666
Change in net unrealized gains (losses) on open contracts	24,875,100		(67,053,724)		2,315,941		(163,313,608)
Total trading results	6,193,641		(27,904,631)		(48,100,507)		(28,596,942)
Net income (loss)	5,185,057		(28,676,714)		(50,225,794)		(30,269,483)
Subscriptions	9,473,871		16,009,192		32,831,819		41,315,481
Redemptions	(78,520,824)		(57,232,435)		(136,170,518)		(88,582,174)
Distribution of interest income to feeder funds	(34,266)		(92,856)		(125,430)		(157,292)
Net increase (decrease) in Partners' Capital	(63,896,162)		(69,992,813)		(153,689,923)		(77,693,468)
Partners' Capital, beginning of period	752,964,392		968,809,937		842,758,153		976,510,592
Partners' Capital, end of period	$ 689,068,230		$ 898,817,124		$ 689,068,230		$ 898,817,124
Net asset value per unit (71,776.9756 and 91,670.4071 units outstanding in June 30, 2013 and 2012, respectively)	9,600.13		9,804.88		9,600.13		9,804.88		10,220.80
Net income (loss) per unit	$ 68.40		$ (306.12)		$ (619.08)		$ (323.06)
Weighted average units outstanding	76,990.8136		95,105.6175		79,462.4536		96,034.5722

[1] Based on change in net asset value per unit.