Summary of Significant Accounting Policies (Details 1) (USD $)	Jun. 30, 2012	Dec. 31, 2011
Short-Term Investments:
Short-Term Investments	$ 163,433,325	$ 175,626,953
Derivatives:
Total	163,884,833	170,153,666
U.S. Government and Agency Obligations [Member]
Short-Term Investments:
Short-Term Investments	149,832,352	174,425,536
Repurchase Agreements [Member]
Short-Term Investments:
Short-Term Investments	13,600,973	1,201,417
Futures Contracts [Member]
Short-Term Investments:
Short-Term Investments	2,788,740
Derivatives:
Net Derivative Fair Value		(4,921,830)
Call Options Written [Member]
Derivatives:
Net Derivative Fair Value	(2,337,232)	(551,457)
Level 1 [Member]
Derivatives:
Total	603,624	(5,470,257)
Level 1 [Member] | U.S. Government and Agency Obligations [Member]
Short-Term Investments:
Short-Term Investments	0	0
Level 1 [Member] | Repurchase Agreements [Member]
Short-Term Investments:
Short-Term Investments	0	0
Level 1 [Member] | Futures Contracts [Member]
Short-Term Investments:
Short-Term Investments	2,788,740
Derivatives:
Net Derivative Fair Value		(4,921,830)
Level 1 [Member] | Call Options Written [Member]
Derivatives:
Net Derivative Fair Value	(2,185,116)	(548,427)
Level 2 [Member]
Derivatives:
Total	163,281,209	175,623,923
Level 2 [Member] | U.S. Government and Agency Obligations [Member]
Short-Term Investments:
Short-Term Investments	149,832,352	174,425,536
Level 2 [Member] | Repurchase Agreements [Member]
Short-Term Investments:
Short-Term Investments	13,600,973	1,201,417
Level 2 [Member] | Futures Contracts [Member]
Short-Term Investments:
Short-Term Investments	0
Derivatives:
Net Derivative Fair Value		0
Level 2 [Member] | Call Options Written [Member]
Derivatives:
Net Derivative Fair Value	(152,116)	(3,030)
Level 3 [Member]
Derivatives:
Total	0	0
Level 3 [Member] | U.S. Government and Agency Obligations [Member]
Short-Term Investments:
Short-Term Investments	0	0
Level 3 [Member] | Repurchase Agreements [Member]
Short-Term Investments:
Short-Term Investments	0	0
Level 3 [Member] | Futures Contracts [Member]
Short-Term Investments:
Short-Term Investments	0
Derivatives:
Net Derivative Fair Value		0
Level 3 [Member] | Call Options Written [Member]
Derivatives:
Net Derivative Fair Value	$ 0	$ 0