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Derivative Instruments and Hedging Activities (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2021	Oct. 31, 2020	Oct. 31, 2021	Oct. 31, 2020	Apr. 30, 2021
Derivative Instruments and Hedging Activities [Abstract]
Total debt outstanding	$ 1,045,005		$ 1,045,005		$ 821,588
Unamortized debt issuance costs	400		400		500
Variable rate loans outstanding	1,045,400		1,045,400
Interest Rate Swaps [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member]
Derivative Instruments and Hedging Activities [Abstract]
Notional amount of derivative liability	400,000		400,000		400,000
Interest Rate Swaps [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member] \| Interest Expense [Member]
Derivative Instruments and Hedging Activities [Abstract]
Net losses reclassified from Accumulated other comprehensive loss	1,100	$ 900	2,200	$ 1,800
Interest Rate Swaps [Member] \| Recurring [Member] \| Level 2 [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member]
Derivative Instruments and Hedging Activities [Abstract]
Liabilities of derivative instrument	3,200		3,200
Interest Rate Swaps [Member] \| Recurring [Member] \| Level 2 [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member] \| Other Non-current Assets [Member]
Derivative Instruments and Hedging Activities [Abstract]
Assets fair value of derivative instrument	700		700
Interest Rate Swaps [Member] \| Recurring [Member] \| Level 2 [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member] \| Other Accrued Liabilities [Member]
Derivative Instruments and Hedging Activities [Abstract]
Liabilities of derivative instrument	2,100		2,100
Interest Rate Swaps [Member] \| Recurring [Member] \| Level 2 [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member] \| Other Long-term Liabilities [Member]
Derivative Instruments and Hedging Activities [Abstract]
Liabilities of derivative instrument	$ 1,100		$ 1,100		$ 5,600