ROYALTY AGREEMENT, UNALLOCATED RESERVE AND DISTRIBUTIONS (Details) - USD ($)		3 Months Ended		6 Months Ended
	Jul. 12, 2021	Jul. 31, 2021	Jul. 31, 2020	Jul. 31, 2021	Jul. 31, 2020	Jan. 31, 2021
Unallocated Cash and Securities portion of Unallocated Reserve
Cash and U.S. Government securities		$ 28,310,067		$ 28,310,067		$ 22,407,610
Distribution payable		(1,180,801)		(1,180,801)		(6,035,205)
Unallocated cash and U.S. Government securities		27,129,266		27,129,266		$ 16,372,405
Reconciliation of Trust's Unallocated Reserve
Beginning Balance		13,374,110	$ 6,095,432	16,477,049	$ 11,831,017
Net income		26,756,030	6,676,003	35,329,900	8,287,624
Distributions declared		(1,180,801)	(656,001)	(12,857,610)	(8,003,207)
Ending Balance		$ 38,949,339	$ 12,115,434	$ 38,949,339	$ 12,115,434
Distributions declared per unit (in dollars per unit)	$ 0.09	$ 0.0900	$ 0.0500	$ 0.9800	$ 0.6100
Distribution declared per unit		$ 0.0900	$ 0.0500
Unallocated Reserve member
Reconciliation of Trust's Unallocated Reserve
Beginning Balance		$ 13,374,107	$ 6,095,429	$ 16,477,046	$ 11,831,014
Net income		26,756,030	6,676,003	35,329,900	8,287,624
Distributions declared		(1,180,801)	(656,001)	(12,857,610)	(8,003,207)
Ending Balance		38,949,336	12,115,431	38,949,336	12,115,431
Trust Corpus
Reconciliation of Trust's Unallocated Reserve
Beginning Balance		3	3	3	3
Ending Balance		$ 3	$ 3	$ 3	$ 3