Schedule of Investments (Unaudited) - Future Contracts - USD ($)		Jun. 30, 2015	Dec. 31, 2014
LME Aluminum (1,418 contracts, settlement date October 19, 2015) [Member]
Schedule of Investments [Line Items]
Unrealized Appreciation/(Depreciation) as a Percentage of Shareholders' Equity		(4.99%)
Unrealized Appreciation/ (Depreciation)	[1]	$ (9,353,669)
Notional Market Value		$ 60,185,238
LME Copper (440 contracts, settlement date August 17, 2015) [Member]
Schedule of Investments [Line Items]
Unrealized Appreciation/(Depreciation) as a Percentage of Shareholders' Equity		(3.78%)
Unrealized Appreciation/ (Depreciation)	[1]	$ (7,077,762)
Notional Market Value		$ 63,371,000
LME Zinc (1,268 contracts, settlement date February 15, 2016) [Member]
Schedule of Investments [Line Items]
Unrealized Appreciation/(Depreciation) as a Percentage of Shareholders' Equity		(3.60%)
Unrealized Appreciation/ (Depreciation)	[1]	$ (6,739,650)
Notional Market Value		$ 63,764,550
Total Commodity Futures Contracts [Member]
Schedule of Investments [Line Items]
Unrealized Appreciation/(Depreciation) as a Percentage of Shareholders' Equity		(12.37%)	(6.11%)
Unrealized Appreciation/ (Depreciation)	[1]	$ (23,171,081)	$ (13,474,175)
Notional Market Value		$ 187,320,788	$ 233,434,763
LME Aluminum (1,605 contracts, settlement date October 19, 2015) [Member]
Schedule of Investments [Line Items]
Unrealized Appreciation/(Depreciation) as a Percentage of Shareholders' Equity			(4.44%)
Unrealized Appreciation/ (Depreciation)	[1]		$ (9,797,319)
Notional Market Value			$ 75,665,719
LME Copper (494 contracts, settlement date February 16, 2015) [Member]
Schedule of Investments [Line Items]
Unrealized Appreciation/(Depreciation) as a Percentage of Shareholders' Equity			(0.61%)
Unrealized Appreciation/ (Depreciation)	[1]		$ (1,336,762)
Notional Market Value			$ 78,138,450
LME Zinc (1,467 contracts, settlement date February 16, 2015 [Member]
Schedule of Investments [Line Items]
Unrealized Appreciation/(Depreciation) as a Percentage of Shareholders' Equity			(1.06%)
Unrealized Appreciation/ (Depreciation)	[1]		$ (2,340,094)
Notional Market Value			$ 79,630,594

[1] Unrealized appreciation/(depreciation) is presented above, net by contract.