Derivative Instruments (Details 4) (USD $)	Mar. 31, 2013	Dec. 31, 2012
Derivative Instruments
Gross amounts recognized	$ 25,487,390	$ 24,588,435
Gross amounts offset	(21,059,000)	(20,907,216)
Net amounts presented in Consolidated Statements of Financial Condition	4,428,390	3,681,219
Agricultural contracts
Derivative Instruments
Gross amounts recognized	759,836	1,010,073
Gross amounts offset	(2,573,786)	(846,892)
Net amounts presented in Consolidated Statements of Financial Condition	(1,813,950)	163,181
Currencies contracts
Derivative Instruments
Gross amounts recognized	4,575,507	12,045,469
Gross amounts offset	(5,368,190)	(7,703,776)
Net amounts presented in Consolidated Statements of Financial Condition	(792,683)	4,341,693
Energy contracts
Derivative Instruments
Gross amounts recognized	1,485,735	1,028,505
Gross amounts offset	(508,401)	(400,364)
Net amounts presented in Consolidated Statements of Financial Condition	977,334	628,141
Interest rates contracts
Derivative Instruments
Gross amounts recognized	6,619,077	2,816,093
Gross amounts offset	(1,294,857)	(2,237,432)
Net amounts presented in Consolidated Statements of Financial Condition	5,324,220	578,661
Meats contracts
Derivative Instruments
Gross amounts recognized	100,979	11,264
Gross amounts offset	(191,103)	(73,450)
Net amounts presented in Consolidated Statements of Financial Condition	(90,124)	(62,186)
Metals contracts
Derivative Instruments
Gross amounts recognized	7,092,175	4,252,379
Gross amounts offset	(7,820,604)	(6,777,973)
Net amounts presented in Consolidated Statements of Financial Condition	(728,429)	(2,525,594)
Soft commodities contracts
Derivative Instruments
Gross amounts recognized	1,443,706	745,230
Gross amounts offset	(202,171)	(333,162)
Net amounts presented in Consolidated Statements of Financial Condition	1,241,535	412,068
Stock indices
Derivative Instruments
Gross amounts recognized	3,410,375	2,679,422
Gross amounts offset	(3,099,888)	(2,534,167)
Net amounts presented in Consolidated Statements of Financial Condition	$ 310,487	$ 145,255