Amount of discretionary contributions made by an employer to a defined benefit plan.

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Amount of benefits for defined benefit plan expected to be paid in periods following the current period.

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Amount of benefits for defined benefit plan expected to be paid in five fiscal years after fifth fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in next fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in fifth fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in fourth fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in third fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in second fiscal year following latest fiscal year.

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Amount of contributions expected to be received by defined benefit plan from employer in next fiscal year following latest fiscal year.

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Amount of net periodic benefit cost (credit) for defined benefit plan.

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Amount of gain (loss) recognized in net periodic benefit (cost) credit from event reducing expected years of future service of present employees or eliminating accrual of defined benefits for some or all future services of present employees.

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Amount of cost for defined contribution plan.

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Amount of liability for retirement benefits, classified as other.

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Retirement Plans, Expected Employer Contributions and Benefit Payments and Other Retirement Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2019	Apr. 30, 2018	Apr. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Expected employer contributions to the defined benefit pension plans	$ 17,000
Discretionary contribution	10,000
Expected future benefit payments [Abstract]
2020	25,155
2021	24,351
2022	25,913
2023	26,692
2024	27,533
2025-2029	147,785
Total	277,429
U.S. [Member]
Expected future benefit payments [Abstract]
2020	16,287
2021	14,741
2022	14,894
2023	15,259
2024	15,436
2025-2029	76,053
Total	152,670
Other postretirement benefits [Abstract]
Annual (credits) expenses for benefit plans	113	$ 647	$ 9,655
Non-U.S. [Member]
Expected future benefit payments [Abstract]
2020	8,868
2021	9,610
2022	11,019
2023	11,433
2024	12,097
2025-2029	71,732
Total	124,759
Other postretirement benefits [Abstract]
Annual (credits) expenses for benefit plans	(7,893)	(7,641)	(3,150)
Non-U.S. [Member] \| Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected employer contributions to the defined benefit pension plans	11,700
Postretirement Life Insurance and Health Care Benefits [Member]
Other postretirement benefits [Abstract]
Curtailment gain (loss)	2,500
Accumulated post-retirement benefit obligation	1,600	1,800
Annual (credits) expenses for benefit plans	(100)	(100)	(200)
Defined Contribution Savings Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Expense recorded	$ 13,100	$ 14,400	$ 15,500