Long-Term Debt - Acquisition Debt (Details) $ in Thousands					12 Months Ended
	Mar. 06, 2020 USD ($)	Sep. 30, 2019 USD ($)	Jun. 01, 2018 USD ($)	Jun. 07, 2017 USD ($)	Apr. 30, 2020 USD ($) loan	Apr. 30, 2019 USD ($)	Apr. 30, 2018 USD ($)
Long-term debt
Loan repayment						$ 571,840	$ 477,616
Write-off of debt discount and deferred financing fees					$ 1,331		74
Term Loan Facility
Long-term debt
Loan repayment			$ 571,800	$ 477,600
Write-off of debt discount and deferred financing fees					$ 1,300
Borrowing interest rate (as a percent)					3.15%
Repayments of debt	$ 50,000	$ 50,000
First Lien Term Loan
Long-term debt
Loan amortization installment frequency					quarterly
Loan amortization installments					$ 2,500
Loan amortization installments (as a percent)					0.25%
First Lien Term Loan | Minimum
Long-term debt
Number of incremental loans | loan					1
First Lien Term Loan | Maximum
Long-term debt
Fixed amount of incremental loan					$ 100,000
Second amendment to First Lien Credit Agreement
Long-term debt
Aggregate principal amount				$ 577,600
Reduction to interest rate margin at each pricing level (as a percent)				0.50%
Write-off of debt discount and deferred financing fees							$ 100
Second amendment to First Lien Credit Agreement | LIBOR
Long-term debt
Margin added to variable rate (as a percent)				3.00%
Variable rate floor (as a percent)				1.00%
Third Amendment
Long-term debt
Aggregate principal amount			$ 996,800
Third Amendment | LIBOR
Long-term debt
Margin added to variable rate (as a percent)			2.75%
Variable rate floor (as a percent)			0.00%
ABL Facility
Long-term debt
Loan repayment					$ 94,000
Borrowing interest rate (as a percent)					1.82%