Leases - Narrative (Details) $ in Millions	3 Months Ended
	Oct. 31, 2019 USD ($)
Lessee, Lease, Description [Line Items]
Option to extend operating leases	10 years
Option to extend operating subleases	4 years
Leases not yet commenced	$ 19
Minimum
Lessee, Lease, Description [Line Items]
Operating lease terms	1 year
Operating sublease terms	1 year
Terms for leases not yet commenced	5 years
Maximum
Lessee, Lease, Description [Line Items]
Operating lease terms	11 years
Operating sublease terms	5 years
Terms for leases not yet commenced	10 years