Operating Leases (Schedule of rental expense) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2021	Jan. 31, 2020
Leases [Abstract]
Sublease income	$ 1,740,248	$ 1,766,609	$ 3,468,281	$ 3,521,861
Operating lease cost	(832,707)	(760,191)	(1,665,420)	(1,510,057)
Excess of sublease income over lease cost	$ 907,541	$ 1,006,418	$ 1,802,861	$ 2,011,804