RELATED PARTY TRANSACTIONS - Fund Management Fees (Details) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Related Party Transaction [Line Items]
Management fees paid	$ 78,844	$ 257,970	$ 87,688	$ 1,165,824
Series 15
Related Party Transaction [Line Items]
Management fees paid	0	62,500	0	62,500
Series 16
Related Party Transaction [Line Items]
Management fees paid	70,000	80,083	70,000	155,683
Series 17
Related Party Transaction [Line Items]
Management fees paid	8,844	12,219	17,688	24,438
Series 18
Related Party Transaction [Line Items]
Management fees paid	0	100,000	0	915,520
Series 19
Related Party Transaction [Line Items]
Management fees paid	$ 0	$ 3,168	$ 0	$ 7,683