Consolidated Statement of Assets, Liabilities and Shareholders' Equity (Parenthetical) (USD $)	Jun. 30, 2011	Dec. 31, 2010
Consolidated Statement of Assets, Liabilities and Shareholders' Equity
Investments at value, cost	$ 1,203,146,096	$ 1,232,484,311
Financial derivatives - assets, cost	136,936,637	208,958,359
Repurchase agreements, cost	22,437,500	25,683,750
Investments sold short at value, proceeds	542,110,655	775,781,612
Financial derivatives - liabilities, proceeds	$ 4,255,004	$ 17,718,129
Common stock, par value	$ 0	$ 0
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	16,507,381	16,498,342
Common stock, shares outstanding	16,507,381	16,498,342