Debt - Accounts Receivable Securitization Facility (Details) - Energy Services - Receivables Facility - Energy Services Receivables Facility - USD ($)	6 Months Ended
Oct. 31, 2019	Apr. 30, 2019
Short-term Debt
Maximum borrowing capacity		$ 150,000,000
Subsequent Event
Short-term Debt
Maximum borrowing capacity	$ 75,000,000

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