Retirement Plans, Changes in and Status of Defined Benefit Plans' Assets and Benefit Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2016
CHANGE IN PLAN ASSETS [Roll Forward]
Fair Value of Plan Assets, Beginning of Year	$ 590,134
Fair Value, End of Year	624,431	$ 590,134
AMOUNTS RECOGNIZED ON THE STATEMENT OF FINANCIAL POSITION [Abstract]
Current Pension Liability	(5,598)	(5,776)
U.S. [Member]
CHANGE IN PLAN ASSETS [Roll Forward]
Fair Value of Plan Assets, Beginning of Year	200,001	215,923
Actual Return on Plan Assets	15,352	17,345
Employer Contributions	5,020	10,463
Employee Contributions	0	0
Settlements	0	(28,258)
Benefits Paid	(15,390)	(15,472)
Foreign Currency Rate Changes	0	0
Fair Value, End of Year	204,983	200,001	$ 215,923
CHANGE IN PROJECTED BENEFIT OBLIGATION [Roll Forward]
Benefit Obligation, Beginning of Year	(290,785)	(336,908)
Service Cost	0	0	0
Interest Cost	(11,666)	(12,398)	(13,612)
Actuarial Gains (Losses)	7,417	14,791
Benefits Paid	15,390	15,472
Foreign Currency Rate Changes	0	0
Settlements and Other	0	28,258
Benefit Obligation, End of Year	(279,644)	(290,785)	(336,908)
Underfunded Status, End of Year	(74,661)	(90,784)
AMOUNTS RECOGNIZED ON THE STATEMENT OF FINANCIAL POSITION [Abstract]
Other Noncurrent Assets	0	0
Current Pension Liability	(4,818)	(4,977)
Noncurrent Pension Liability	(69,843)	(85,807)
Net Amount Recognized in Statement of Financial Position	(74,661)	(90,784)
AMOUNTS RECOGNIZED IN ACCUMULATED OTHER COMPREHENSIVE LOSS (BEFORE TAX) CONSIST OF [Abstract]
Net Actuarial (Losses)	(82,636)	(94,539)
Prior Service Cost Gains (Losses)	2,562	2,716
Total Accumulated Other Comprehensive Loss	(80,074)	(91,823)
Change in Accumulated Other Comprehensive Loss	$ 11,749	$ 29,394
WEIGHTED AVERAGE ASSUMPTIONS USED IN DETERMINING ASSETS AND LIABILITIES [Abstract]
Discount Rate	4.30%	4.10%
Rate of Compensation Increase
Accumulated Benefit Obligations	$ (279,644)	$ (290,785)
Non-U.S. [Member]
CHANGE IN PLAN ASSETS [Roll Forward]
Fair Value of Plan Assets, Beginning of Year	390,133	352,484
Actual Return on Plan Assets	2,780	75,432
Employer Contributions	8,385	14,041
Employee Contributions	0	0
Settlements	(239)	0
Benefits Paid	(15,909)	(9,487)
Foreign Currency Rate Changes	34,298	(42,337)
Fair Value, End of Year	419,448	390,133	352,484
CHANGE IN PROJECTED BENEFIT OBLIGATION [Roll Forward]
Benefit Obligation, Beginning of Year	(519,588)	(461,161)
Service Cost	(960)	(967)	(1,455)
Interest Cost	(13,876)	(14,449)	(16,446)
Actuarial Gains (Losses)	23,528	(105,151)
Benefits Paid	15,909	9,487
Foreign Currency Rate Changes	(45,938)	52,653
Settlements and Other	239	0
Benefit Obligation, End of Year	(540,686)	(519,588)	$ (461,161)
Underfunded Status, End of Year	(121,238)	(129,455)
AMOUNTS RECOGNIZED ON THE STATEMENT OF FINANCIAL POSITION [Abstract]
Other Noncurrent Assets	0	134
Current Pension Liability	(780)	(799)
Noncurrent Pension Liability	(120,458)	(128,790)
Net Amount Recognized in Statement of Financial Position	(121,238)	(129,455)
AMOUNTS RECOGNIZED IN ACCUMULATED OTHER COMPREHENSIVE LOSS (BEFORE TAX) CONSIST OF [Abstract]
Net Actuarial (Losses)	(183,316)	(171,601)
Prior Service Cost Gains (Losses)	(441)	(448)
Total Accumulated Other Comprehensive Loss	(183,757)	(172,049)
Change in Accumulated Other Comprehensive Loss	$ (11,708)	$ (32,221)
WEIGHTED AVERAGE ASSUMPTIONS USED IN DETERMINING ASSETS AND LIABILITIES [Abstract]
Discount Rate	2.60%	2.60%
Rate of Compensation Increase	3.00%	3.00%
Accumulated Benefit Obligations	$ (507,932)	$ (472,841)