Leases - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Jul. 31, 2020
Leases [Abstract]
Operating cash flows from operating leases	$ 3,855	$ 3,005
Operating leases	$ 2,348	$ 278
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesCurrent		us-gaap:OtherLiabilitiesCurrent
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesNoncurrent		us-gaap:OtherLiabilitiesNoncurrent
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesCurrent		us-gaap:OtherLiabilitiesCurrent
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesNoncurrent		us-gaap:OtherLiabilitiesNoncurrent