Leases (Right-of-use Assets and Lease Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Apr. 30, 2020
Leases [Abstract]
Right-of-use assets, Operating leases	$ 93,412	$ 111,815
Right-of-use assets, Finance leases	$ 1,858
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Property, Plant and Equipment, Net
Total right-of-use assets	$ 95,270
Current liabilities: Operating leases	30,608
Current liabilities: Finance leases	568
Noncurrent liabilities: Operating leases	75,396
Noncurrent liabilities: Finance leases	$ 1,225
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Long-term Debt, Excluding Current Maturities
Total lease liabilities	$ 107,797