Leases - Future minimum lease payments under non-cancellable leases (Details) $ in Thousands	Apr. 30, 2020 USD ($)
Finance lease
2021	$ 46,116
2022	39,328
2023	30,525
2024	21,234
2025	10,544
Thereafter	3,647
Total lease payments	151,394
Less imputed interest	22,627
Total	128,767
Operating lease
2021	38,960
2022	30,387
2023	23,655
2024	18,775
2025	12,154
Thereafter	16,848
Total lease payments	140,779
Less imputed interest	18,134
Total	$ 122,645