Summary of Significant Accounting Policies - New Accounting Standards (Details) - USD ($) $ in Thousands	Jul. 31, 2020	Aug. 01, 2019
Accounting Policies [Abstract]
Right of use assets	$ 44,267	$ 35,842
Lease liability	46,367
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Lease liability	$ 46,367
Lease liability current
Accounting Policies [Abstract]
Lease liability		36,417
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Lease liability		36,417
Long-term lease liabilities
Accounting Policies [Abstract]
Lease liability		36,417
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Lease liability		$ 36,417