Leases - Future minimum lease payments under non-cancellable leases (Details) $ in Thousands	Jul. 31, 2020 USD ($)
Finance lease
2021 (remaining nine months)	$ 34,510
2022	40,070
2023	31,317
2024	22,022
2025	11,199
Thereafter	4,154
Total lease payments	143,272
Less imputed interest	19,954
Total	123,318
Operating lease
2021 (remaining nine months)	29,899
2022	32,039
2023	25,153
2024	20,281
2025	13,667
Thereafter	16,732
Total lease payments	137,771
Less imputed interest	17,383
Total	$ 120,388