Leases - Supplemental balance sheet (Details) $ in Thousands	Apr. 30, 2020 USD ($)
Assets:
Operating lease assets	$ 45,399
Finance lease assets	4,606
Right-of-use assets, net	50,005
Liabilities:
Operating lease liabilities	9,877
Finance lease liabilities	392
Current portion of lease liabilities	10,269
Operating lease liabilities	37,473
Finance lease liabilities	4,228
Long-term lease liabilities	41,701
Total lease liabilities	$ 51,970
Weighted average remaining lease term:
Operating leases	6 years 3 months 7 days
Finance leases	6 years 7 days
Weighted average discount rate:
Operating leases	2.75%
Finance leases	23.39%