Leases - Components of Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2021	Jan. 31, 2020
Leases [Abstract]
Operating lease cost	$ 3,881	$ 3,112	$ 7,758	$ 6,143
Amortization of right-of-use assets	175	136	311	272
Interest on lease liabilities	131	134	257	271
Total lease cost	$ 4,187	$ 3,382	$ 8,326	$ 6,686