Leases- Maturities of lease liabilities (Detail) $ in Thousands	Apr. 30, 2019 USD ($)
Leases [Abstract]
Operating Leases, Remaining for Fiscal 2020	$ 4,102
Operating Leases, Period Fiscal 2021	4,806
Operating Leases, Period Fiscal 2022	4,014
Operating Leases, Period Fiscal 2023	2,491
Operating Leases, Period Fiscal 2024	1,822
Operating Leases, Thereafter	1,494
Operating Leases, Total lease payments	18,729
Operating Leases, Less imputed interest	(1,611)
Operating Leases	17,118
Finance Leases, Remaining for Fiscal 2020	809
Finance Leases, Period Fiscal 2021	1,078
Finance Leases, Period Fiscal 2022	359
Finance Leases, Total lease payments	2,246
Finance Leases, Less imputed interest	(94)
Finance Leases	$ 2,152