Summary of Significant Accounting Policies New Accounting Pronouncements (Details) - USD ($) $ in Thousands	Jul. 31, 2020	Aug. 01, 2019	Jul. 31, 2019
Accounting Standards Update and Change in Accounting Principle [Abstract]
Operating lease assets	$ 41,899	$ 55,984	$ 0
Operating Lease, Liability	$ 47,286	$ 58,544