Retirement Plans, Changes in and Status of Defined Benefit Plans' Assets and Benefit Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2015
CHANGE IN PLAN ASSETS [Roll Forward]
Fair Value of Plan Assets, Beginning of Year	$ 568,407
Fair Value, End of Year	590,134	$ 568,407
AMOUNTS RECOGNIZED IN THE STATEMENT OF FINANCIAL POSITION [Abstract]
Current Pension Liability	(5,776)	(5,492)
U.S. Plans [Member]
CHANGE IN PLAN ASSETS [Roll Forward]
Fair Value of Plan Assets, Beginning of Year	215,923	222,966
Actual Return on Plan Assets	17,345	2,610
Employer Contributions	10,463	9,459
Employee Contributions	0	0
Settlements	(28,258)	(4,446)
Benefits Paid	(15,472)	(14,666)
Foreign Currency Rate Changes	0	0
Fair Value, End of Year	200,001	215,923	$ 222,966
CHANGE IN PROJECTED BENEFIT OBLIGATION [Roll Forward]
Benefit Obligation, Beginning of Year	(336,908)	(329,388)
Service Cost	0	0	0
Interest Cost	(12,398)	(13,612)	(13,159)
Employee Contributions	0	0
Actuarial Gain (Loss)	14,791	(13,020)
Benefits Paid	15,472	14,666
Foreign Currency Rate Changes	0	0
Settlements and Other	28,258	4,446
Benefit Obligation, End of Year	(290,785)	(336,908)	(329,388)
Funded Status	(90,784)	(120,985)
AMOUNTS RECOGNIZED IN THE STATEMENT OF FINANCIAL POSITION [Abstract]
Other Noncurrent Assets	0	0
Current Pension Liability	(4,977)	(4,817)
Noncurrent Pension Liability	(85,807)	(116,168)
Net Amount Recognized in Statement of Financial Position	(90,784)	(120,985)
AMOUNTS RECOGNIZED IN ACCUMULATED OTHER COMPREHENSIVE LOSS (before tax) CONSIST OF [Abstract]
Net Actuarial (Loss)	(94,539)	(124,087)
Prior Service Cost Gain (Loss)	2,716	2,870
Total Accumulated Other Comprehensive Loss	(91,823)	(121,217)
Change in Accumulated Other Comprehensive Loss	$ 29,394	$ (21,224)
WEIGHTED AVERAGE ASSUMPTIONS USED IN DETERMINING ASSETS AND LIABILITIES [Abstract]
Discount Rate	4.10%	4.00%
Rate of Compensation Increase
Accumulated Benefit Obligations	$ (290,785)	$ (336,908)
Non-U.S. Plans [Member]
CHANGE IN PLAN ASSETS [Roll Forward]
Fair Value of Plan Assets, Beginning of Year	352,484	376,576
Actual Return on Plan Assets	75,432	(2,789)
Employer Contributions	14,041	8,450
Employee Contributions	0	68
Settlements	0	0
Benefits Paid	(9,487)	(14,354)
Foreign Currency Rate Changes	(42,337)	(15,467)
Fair Value, End of Year	390,133	352,484	376,576
CHANGE IN PROJECTED BENEFIT OBLIGATION [Roll Forward]
Benefit Obligation, Beginning of Year	(461,161)	(484,458)
Service Cost	(967)	(1,455)	(5,942)
Interest Cost	(14,449)	(16,446)	(17,417)
Employee Contributions	0	(68)
Actuarial Gain (Loss)	(105,151)	9,582
Benefits Paid	9,487	14,354
Foreign Currency Rate Changes	52,653	17,330
Settlements and Other	0	0
Benefit Obligation, End of Year	(519,588)	(461,161)	$ (484,458)
Funded Status	(129,455)	(108,677)
AMOUNTS RECOGNIZED IN THE STATEMENT OF FINANCIAL POSITION [Abstract]
Other Noncurrent Assets	134	0
Current Pension Liability	(799)	(675)
Noncurrent Pension Liability	(128,790)	(108,002)
Net Amount Recognized in Statement of Financial Position	(129,455)	(108,677)
AMOUNTS RECOGNIZED IN ACCUMULATED OTHER COMPREHENSIVE LOSS (before tax) CONSIST OF [Abstract]
Net Actuarial (Loss)	(171,601)	(139,307)
Prior Service Cost Gain (Loss)	(448)	(521)
Total Accumulated Other Comprehensive Loss	(172,049)	(139,828)
Change in Accumulated Other Comprehensive Loss	$ (32,221)	$ (10,993)
WEIGHTED AVERAGE ASSUMPTIONS USED IN DETERMINING ASSETS AND LIABILITIES [Abstract]
Discount Rate	2.60%	3.50%
Rate of Compensation Increase	3.00%	3.00%
Accumulated Benefit Obligations	$ (472,841)	$ (422,861)