INCOME TAXES Income Tax Effective Rate Reconciliation (Details)	12 Months Ended
	Jul. 31, 2020	Jul. 31, 2019
U.S. federal income tax rate	21.00%	21.00%
Depletion deductions allowed for mining	(4.80%)	(8.20%)
State income tax expense, net of federal tax expense	4.30%	2.50%
Difference in effective tax rate of foreign subsidiaries	1.20%	0.20%
Prior year income taxes	(1.00%)	(1.90%)
Other	(2.10%)	(0.30%)
Effective income tax rate	18.60%	13.30%