Deferred Compensation And Retirement Plans (Total Long-Term Benefit Obligations) (Detail) - USD ($) $ in Thousands	Apr. 30, 2015	Apr. 30, 2014	Apr. 30, 2013	Apr. 30, 2012
Defined Benefit Plan Disclosure [Line Items]
Total benefit obligation	$ 191,446	$ 179,612
Less: current portion of benefit obligation	(18,014)	(10,377)
Non-current benefit obligation	173,432	169,235
Total benefit obligations	191,446	179,612
Deferred Compensation Plan
Defined Benefit Plan Disclosure [Line Items]
Total benefit obligation	83,876	82,153	$ 85,562	$ 78,479
Less: current portion of benefit obligation	(5,554)	(5,593)	(5,182)
Non-current benefit obligation	78,322	76,560	80,380
Total benefit obligations	83,876	82,153	85,562	78,479
Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Total benefit obligation	5,262	4,424	4,536	4,214
Less: current portion of benefit obligation	(278)	(274)	(232)
Non-current benefit obligation	4,984	4,150	4,304
Total benefit obligations	5,262	4,424	4,536	$ 4,214
International Retirement Plans
Defined Benefit Plan Disclosure [Line Items]
Total benefit obligation	2,847	3,727
Total benefit obligations	2,847	3,727
Executive Capital Accumulation Plan
Defined Benefit Plan Disclosure [Line Items]
Total benefit obligation	99,461	89,308	75,913
Less: current portion of benefit obligation	(12,182)	(4,510)
Non-current benefit obligation	87,279	84,798
Total benefit obligations	$ 99,461	$ 89,308	$ 75,913