Long-Term Debt - Asset-Based Lending Facility (Details) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2020	Jul. 31, 2019
Long-term debt
Net borrowings	$ 14,421	$ 274,810
Net repayments	58,083	$ 262,107
ABL Facility
Long-term debt
Maximum amount under the facility	$ 445,000
Borrowing interest rate (as a percent)	1.43%
Available borrowings under the facility	$ 353,900
Net repayments	40,000
ABL Facility | Swing-line
Long-term debt
Maximum amount under the facility	$ 44,500