XML 50 R27.htm IDEA: XBRL DOCUMENT v2.4.0.8
Financial Highlights (Per Unit Performance Data and Other Supplemental Financial Data) (Details) (USD $)
 9 Months Ended
Sep. 30, 2014
Sep. 30, 2013
Dec. 06, 2007
Per Share Operating Performance:      
Net asset value, beginning of period $ 42.83 $ 39.81 $ 50.00
Total income (loss) $ (0.72) $ 3.69  
Total expenses $ (0.31) $ (0.31)  
Net increase (decrease) in net asset value $ (1.03) $ 3.38  
Net asset value, end of period $ 41.80 $ 43.19 $ 50.00
Total Return (2.40%) 8.49%  
Ratios to Average Net Assets      
Total income (loss) (1.31%) 7.86%  
Expenses excluding management fees 0.33% [1] 0.40% [1]  
Management fees 0.60% [1] 0.60% [1]  
Net income (loss) (2.00%) 7.11%  
[1] Annualized