Leases (Details) $ in Thousands	6 Months Ended
	Feb. 29, 2020 USD ($)
Leases
Package of practical expedients	true
Assets
Operating lease right-of-use asset (Note 8)	$ 9,256
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Us-gaap:OtherNoncurrentAssetsMember
Current (accrued expense)	$ 2,053
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Us-gaap:AccruedLiabilitiesMember
Other non-current liabilities	$ 6,648
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Us-gaap:OtherNoncurrentLiabilitiesMember
Present value of lease liabilities	$ 8,701