DERIVATIVE INSTRUMENTS HEDGING AND NON-HEDGING ACTIVITIES - Asset and Liabilities Subject to Master Netting Agreements (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Assets
Gross amounts of recognized assets		$ 5,349,613
Gross amounts offset in the Balance Sheet		0
Net amount		5,349,613
Financial instruments		0
Cash collateral (Received)/ Pledged		1,123,463
Net Amount	$ 0	4,226,150
Liabilities
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)
Financial instruments		0
Cash collateral (Received)/ Pledged		0
Net amount		(1,234,522,000)
Repurchase agreements
Liabilities
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)
Financial instruments		0
Cash collateral (Received)/ Pledged		0
Net amount		(1,234,522,000)
Futures
Assets
Gross amounts of recognized assets		5,349,613
Gross amounts offset in the Balance Sheet		0
Net amount		5,349,613
Financial instruments		0
Cash collateral (Received)/ Pledged		1,123,463
Net Amount		$ 4,226,150