Long-Term Debt - Prepayments (Details) - Term Loan Facilities $ in Thousands	12 Months Ended
	Apr. 30, 2020 USD ($)
Long-term debt
Percentage of the net proceeds of certain asset sales and issuances or incurrences of nonpermitted indebtedness to be used for mandatory prepayments	100.00%
Percentage of annual excess cash flow for mandatory prepayments	50.00%
Prepayment required related to excess cash flow	$ 0
Attainment of certain total leverage ratio targets | Maximum
Long-term debt
Percentage of annual excess cash flow for mandatory prepayments	25.00%
Attainment of certain total leverage ratio targets | Minimum
Long-term debt
Percentage of annual excess cash flow for mandatory prepayments	0.00%