Fair Value of Financial Instruments and Long Term Debt - Carrying Value of Long-term Debt (Details) $ in Thousands	12 Months Ended
Apr. 30, 2022 USD ($) installment_payment	Apr. 30, 2021 USD ($) installment_payment
Debt Instrument
Finance lease liabilities (Note 7)	$ 74,234	$ 14,085
Long-term debt	1,615,625
Debt issuance costs	(1,990)	(336)
Total	1,687,869	1,363,749
Less current maturities	24,466	2,354
Long-term debt and finance lease obligations, net of current maturities	1,663,403	1,361,395
Senior Notes \| 3.67% Senior notes (Series A) due in 7 installments beginning June 17, 2022, and ending June 15, 2028
Debt Instrument
Long-term debt	$ 150,000	$ 150,000
Senior Notes \| 3.75% Senior notes (Series B) due in 7 installments beginning December 17, 2022 and ending December 18, 2028
Debt Instrument
Interest rate	3.67%	3.67%
Number of payments \| installment_payment	7	7
Long-term debt	$ 50,000	$ 50,000
Senior Notes \| 3.65% Senior notes (Series C) due in 7 installments beginning May 2, 2025 and ending May 2, 2031
Debt Instrument
Interest rate	3.75%	3.75%
Number of payments \| installment_payment	7	7
Long-term debt	$ 50,000	$ 50,000
Senior Notes \| 3.72% Senior notes (Series D) due in 7 installments beginning October 28, 2025 and ending October 28, 2031
Debt Instrument
Interest rate	3.65%	3.65%
Number of payments \| installment_payment	7	7
Long-term debt	$ 50,000	$ 50,000
Senior Notes \| 3.51% Senior notes (Series E) due June 13, 2025
Debt Instrument
Interest rate	3.72%	3.72%
Number of payments \| installment_payment	7	7
Long-term debt	$ 150,000	$ 150,000
Senior Notes \| 3.77% Senior notes (Series F) due August 22, 2028
Debt Instrument
Interest rate	3.51%
Long-term debt	$ 250,000	250,000
Senior Notes \| 2.85% Senior notes (Series G) due August 7, 2030
Debt Instrument
Interest rate	3.77%
Long-term debt	$ 325,000	325,000
Senior Notes \| 2.96% Senior notes (Series H) due August 6, 2032
Debt Instrument
Interest rate	2.85%
Long-term debt	$ 325,000	325,000
Senior Notes \| Variable rate Term Loan Facilities, due January 6, 2026
Debt Instrument
Interest rate	2.96%
Long-term debt	$ 265,625	$ 0

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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Amount, before accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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- Definition

Present value of lessee's discounted obligation for lease payments from finance lease.

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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