Stock-based Payment Compensation (Details 1) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2021	Jan. 31, 2020
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 8,865	$ 6,141	$ 17,778	$ 11,674
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	7,051	4,704	14,433	9,145
Yard Operations
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 1,814	$ 1,437	$ 3,345	$ 2,529