Stock-based Payment Compensation (Details 1) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2017	Apr. 30, 2016
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 5,008	$ 5,034	$ 15,613	$ 15,834
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	4,180	4,320	13,176	13,758
Yard Operations
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 828	$ 714	$ 2,437	$ 2,076