Commitments and Contingencies (Details Textuals) - USD ($) $ in Millions	12 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2016
Major Operating and Capital Expenses [Abstract]
Outstanding letter of credit	$ 17.3
Facilities Rental Expense
Major Operating and Capital Expenses [Abstract]
Rental expense	45.6	$ 26.8	$ 21.6
Yard Operations Equipment Rental Expense
Major Operating and Capital Expenses [Abstract]
Rental expense	$ 2.8	$ 2.9	$ 3.1