Right-of-Use Assets and Lease Liabilities (Details) - Lessee, Operating Lease, Disclosure - USD ($) $ in Thousands	Apr. 30, 2021	Apr. 30, 2020
Assets
Operating lease ROU assets	$ 9,773	$ 10,864
Liabilities
Operating lease liabilities (short-term)	1,715	1,869
Operating lease liabilities (long-term)	8,366	9,444
Total lease liabilities	$ 10,081	$ 11,313