Leases, Supplemental Cash Flow Information and Non-cash Activity Related to Operating Leases (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jul. 31, 2020	Jul. 31, 2020	Aug. 02, 2019	Aug. 03, 2018
Operating cash flow information [Abstract]
Gain on sale and leaseback transaction	$ 69,954	$ 69,954	$ 0	$ 0
Cash paid for amounts included in the measurement of lease liabilities		80,265
Noncash information [Abstract]
Right-of-use assets obtained in exchange for new operating lease liabilities		267,266
Lease modifications granting additional right-of-use assets		29,793
Lease modifications removing right-of-use assets		$ (19,939)