Employees' Retirement Plan (Details) - USD ($)	3 Months Ended		9 Months Ended
	Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2021	Apr. 30, 2020
Retirement Benefits [Abstract]
Pension contributions	$ 109,760	$ 67,312	$ 329,743	$ 314,897
Employer contributions	$ 17,925	$ 14,360	$ 48,498	$ 46,180
Minimum contribution rate			9.10%