Unaudited Schedule of Investments - Future Contracts (USD $)	Jun. 30, 2014	Dec. 31, 2013
ICE-UK Brent Crude (767 contracts, settlement date November 13, 2014) [Member]
Schedule of Investments [Line Items]
Percentage of Net Assets	1.21%
Unrealized Appreciation/ (Depreciation)	$ 4,442,020
Notional Market Value	84,991,270
NYMEX Natural Gas (921 contracts, settlement date September 26, 2014) [Member]
Schedule of Investments [Line Items]
Percentage of Net Assets	0.90%
Unrealized Appreciation/ (Depreciation)	3,326,290
Notional Market Value	40,837,140
NYMEX NY Harbor (666 contracts, settlement date May 29, 2015) [Member]
Schedule of Investments [Line Items]
Percentage of Net Assets	0.74%
Unrealized Appreciation/ (Depreciation)	2,729,471
Notional Market Value	82,310,407
NYMEX RBOB Gasoline (741 contracts, settlement date November 28, 2014) [Member]
Schedule of Investments [Line Items]
Percentage of Net Assets	1.95%
Unrealized Appreciation/ (Depreciation)	7,192,747
Notional Market Value	85,737,998
NYMEX WTI Crude (872 contracts, settlement date December 19, 2014) [Member]
Schedule of Investments [Line Items]
Percentage of Net Assets	0.97%
Unrealized Appreciation/ (Depreciation)	3,559,680
Notional Market Value	88,420,800
Total Commodity Futures Contracts [Member]
Schedule of Investments [Line Items]
Percentage of Net Assets	5.77%	4.98%
Unrealized Appreciation/ (Depreciation)	21,250,208	13,354,799
Notional Market Value	382,297,615	277,789,405
ICE-UK Brent Crude (568 contracts, settlement date March 14, 2014) [Member]
Schedule of Investments [Line Items]
Percentage of Net Assets		1.60%
Unrealized Appreciation/ (Depreciation)		4,300,830
Notional Market Value		62,633,360
NYMEX Natural Gas (706 contracts, settlement date September 26, 2014) [Member]
Schedule of Investments [Line Items]
Percentage of Net Assets		0.71%
Unrealized Appreciation/ (Depreciation)		1,910,740
Notional Market Value		29,383,720
NYMEX NY Harbor ULSD (491 contracts, settlement date March 31, 2014) [Member]
Schedule of Investments [Line Items]
Percentage of Net Assets		0.67%
Unrealized Appreciation/ (Depreciation)		1,779,124
Notional Market Value		62,763,057
NYMEX RBOB Gasoline (568 contracts, settlement date November 28, 2014) [Member]
Schedule of Investments [Line Items]
Percentage of Net Assets		1.07%
Unrealized Appreciation/ (Depreciation)		2,861,095
Notional Market Value		61,956,418
NYMEX WTI Crude (633 contracts, settlement date June 20, 2014) [Member]
Schedule of Investments [Line Items]
Percentage of Net Assets		0.93%
Unrealized Appreciation/ (Depreciation)		2,503,010
Notional Market Value		$ 61,052,850