DERIVATIVE INSTRUMENTS HEDGING AND NON-HEDGING ACTIVITIES - Asset and Liabilities Subject to Master Netting Agreements (Details) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Derivative [Line Items]
Gross amounts of recognized assets		$ 5,349,613
Gross amounts offset in the Balance Sheet		0
Net amounts of assets presented in the Balance Sheet		5,349,613
Gross amounts not offset in the Balance Sheet, Financial instruments		0
Gross amounts not offset in the Balance Sheet, Cash collateral (Received)/Pledged		(1,123,463)
Net Amount	$ 0	4,226,150
Gross amounts of recognized liabilities		(1,234,522,000)
Gross amounts offset in the Balance Sheet		0
Net amounts of liabilities presented in the Balance Sheet		(1,234,522,000)
Gross amounts not offset in the Balance Sheet, Cash collateral (Received)/Pledged		1,234,522,000
Gross amounts not offset in the Balance Sheet, Cash collateral (Received) / Pledged		0
Net Amount	$ 0	0
Repurchase agreements
Derivative [Line Items]
Gross amounts of recognized liabilities		(1,234,522,000)
Gross amounts offset in the Balance Sheet		0
Net amounts of liabilities presented in the Balance Sheet		(1,234,522,000)
Gross amounts not offset in the Balance Sheet, Cash collateral (Received)/Pledged		1,234,522,000
Gross amounts not offset in the Balance Sheet, Cash collateral (Received) / Pledged		0
Net Amount		0
Futures
Derivative [Line Items]
Gross amounts of recognized assets		5,349,613
Gross amounts offset in the Balance Sheet		0
Net amounts of assets presented in the Balance Sheet		5,349,613
Gross amounts not offset in the Balance Sheet, Financial instruments		0
Gross amounts not offset in the Balance Sheet, Cash collateral (Received)/Pledged		(1,123,463)
Net Amount		$ 4,226,150