Leases - Components of Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Oct. 31, 2020	Oct. 31, 2019
Leases [Abstract]
Operating lease cost	$ 3,877	$ 3,031
Amortization of right-of-use assets	136	136
Interest on lease liabilities	126	137
Total lease cost	$ 4,139	$ 3,304