Commitments and Contingencies - Lease Maturity Schedule (Details) - USD ($) $ in Thousands	Jan. 31, 2020	Apr. 30, 2019
Finance leases
2021	$ 3,115
2022	3,110
2023	3,109
2024	2,897
2025	1,385
Thereafter	10,705
Total minimum lease payments	24,321
Less amount representing interest	6,979
Present value of net minimum lease payments	17,342
Operating leases
2021	1,830
2022	1,791
2023	1,709
2024	1,634
2025	1,556
Thereafter	23,581
Total minimum lease payments	32,101
Less amount representing interest	11,745
Present value of net minimum lease payments	$ 20,356
Capital leases
2020		$ 3,103
2021		3,109
2022		3,096
2023		3,098
2024		2,548
Thereafter		9,215
Total minimum lease payments		24,169
Less amount representing interest		7,689
Present value of net minimum lease payments		16,480
Operating leases
2020		1,703
2021		1,547
2022		1,354
2023		1,228
2024		1,066
Thereafter		10,438
Total minimum lease payments		$ 17,336