LEASES Rental Expense for all operating leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2019	Jul. 31, 2018
Total Rental Expense
Rent Expense, Total	$ 2,873	$ 3,203
Vehicles and Railcars
Total Rental Expense
Rent Expense	1,319	1,404
Office facilities
Total Rental Expense
Rent Expense	626	985
Warehouse facilities
Total Rental Expense
Rent Expense	434	408
Mining properties
Total Rental Expense
Rent Expense, Minimum	118	106
Rent Expense, Contingent	301	208
Other
Total Rental Expense
Rent Expense	$ 75	$ 92