Financial Instruments (Details) (USD $)	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Investment Holdings [Line Items]
Net unrealized gains (losses) on open contracts	$ (1,549,578)	$ (1,225,581)
Cash held by acting commodity futures brokers administrating open contracts	25,721,239	36,356,986
Exchange-Traded [Member]
Investment Holdings [Line Items]
Net unrealized gains (losses) on open contracts	(1,843,372)	(1,456,914)
Longest maturity date	Sep. 30, 2015	Mar. 31, 2015
Off-Exchange-Traded [Member]
Investment Holdings [Line Items]
Net unrealized gains (losses) on open contracts	$ 293,794	$ 231,333
Longest maturity date	Sep. 30, 2014	Mar. 31, 2014