Statements of Financial Condition (Unaudited) (Parenthetical) (USD $)	Jun. 30, 2012	Dec. 31, 2011
Statements of Financial Condition [Abstract]
Short-term investments, at cost	$ 163,429,056	$ 175,594,508
Call options written, at value, premiums received	$ 1,504,277	$ 1,428,047
Common stock, shares authorized	unlimited	unlimited
Common stock, shares issued	9,219,240	9,229,040
Common stock, shares outstanding	9,219,240	9,229,040