NATURE OF BUSINESS AND ORGANIZATION - B/S (Details) - USD ($)	Apr. 30, 2018	Jan. 31, 2018	Apr. 30, 2017	Jan. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cash and cash equivalents	$ 3,029,479	$ 314,835	$ 12,009,469	$ 13,695,168
U.S. Government securities, current, at amortized cost (which approximates market)	8,315,795	23,797,451
Accrued income receivable	4,294,659	1,956,091
Contract asset	1,430,427	99,264
Prepaid expenses	69,151	54,640
Current assets	17,139,511	26,222,281
Amended assignment of Peters Lease	1	1
Assignment of Cloquet Leases	1	1
Certificate of beneficial interest for 13,120,010 units of Land Trust	1	1
Total fixed property	3	3
Total assets	17,139,514	26,222,284
Distribution payable	5,904,005	15,481,612
Accrued expenses	216,988	133,994
Total liabilities	6,120,993	15,615,606
Unallocated reserve	11,018,518	10,606,675
Trust corpus	3	3
Total liabilities, unallocated reserve and trust corpus	$ 17,139,514	26,222,284
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract asset		99,264
Current assets		99,264
Total assets		99,264
Unallocated reserve		99,264
Total liabilities, unallocated reserve and trust corpus		99,264
Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cash and cash equivalents		314,835	$ 12,009,469	$ 13,695,168
U.S. Government securities, current, at amortized cost (which approximates market)		23,797,451
Accrued income receivable		1,956,091
Prepaid expenses		54,640
Current assets		26,123,017
Amended assignment of Peters Lease		1
Assignment of Cloquet Leases		1
Certificate of beneficial interest for 13,120,010 units of Land Trust		1
Total fixed property		3
Total assets		26,123,020
Distribution payable		15,481,612
Accrued expenses		133,994
Total liabilities		15,615,606
Unallocated reserve		10,507,411
Trust corpus		3
Total liabilities, unallocated reserve and trust corpus		$ 26,123,020