Financial Highlights (Tables)

6 Months Ended

Jun. 30, 2013

Disclosure Text Block Supplement [Abstract]

Financial Summary [Table Text Block]

The following financial highlights present the Trust’s financial performance for the three and six month periods ended June 30, 2013 and June 30, 2012. Total return is calculated as the change in a theoretical beneficial owner’s investment over the entire period and is not annualized. Total return is calculated based on the aggregate return of the Trust taken as a whole.

	Class A						Class B						Class A						Class B
	Three months ended						Three months ended						Six months ended						Six months ended
	June 30,						June 30,						June 30,						June 30,
	2013			2012			2013			2012			2013			2012			2013			2012
Per share operating performance:
Net asset value of Trading units, beginning of period	$	75.80		$	86.37		$	82.53		$	92.18		$	76.92		$	91.32		$	83.34		$	96.98
Total Trading income (loss):
Trading gain (loss)		(1.54	)		(0.71	)		(1.68	)		(0.76	)		(0.98	)		(3.86	)		(1.07	)		(4.11	)
Investment income		0.01			0.08			0.00			0.09			0.06			0.22			0.06			0.23
Expenses		(1.72	)		(1.81	)		(1.47	)		(1.48	)		(3.45	)		(3.75	)		(2.95	)		(3.07	)
Trading income (loss)		(3.25	)		(2.44	)		(3.15	)		(2.15	)		(4.37	)		(7.39	)		(3.96	)		(6.95	)
Net asset value of Trading units, end of period	$	72.55		$	83.93		$	79.38		$	90.03		$	72.55		$	83.93		$	79.38		$	90.03
Total return:
Total return before incentive fees		(4.30	%)		(2.81	%)		(3.81	%)		(2.32	%)		(5.68	%)		(8.09	%)		(4.75	%)		(7.14	%)
Less incentive fee allocations		0.00	%		(0.02	%)		0.00	%		(0.02	%)		0.00	%		(0.01	%)		0.00	%		(0.02	%)
Total return		(4.30	%)		(2.83	%)		(3.81	%)		(2.34	%)		(5.68	%)		(8.10	%)		(4.75	%)		(7.16	%)
Ratios to average net assets:
Trading income (loss)		(4.42	%)		(0.75	%)		(3.90	%)		(0.64	%)		(5.72	%)		(4.51	%)		(4.49	%)		(4.48	%)
Expenses:
Expenses, less incentive fees		(2.34	%)		(2.13	%)		(1.83	%)		(1.62	%)		(4.62	%)		(4.34	%)		(3.67	%)		(3.33	%)
Incentive fees		0.00	%		(0.02	%)		0.00	%		(0.02	%)		0.00	%		(0.01	%)		0.00	%		(0.02	%)
Total expenses		(2.34	%)		(2.15	%)		(1.83	%)		(1.64	%)		(4.62	%)		(4.35	%)		(3.67	%)		(3.35	%)