Valuation And Qualifying Accounts (Detail) - USD ($) $ in Thousands		12 Months Ended
		Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2014
Allowance for Doubtful Accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period		$ 9,958	$ 9,513	$ 9,097
Charges to Cost and Expenses		8,570	7,741	7,840
(Charges) Recoveries to Other Accounts	[1]	(270)	(693)	291
Deductions	[2]	(6,966)	(6,603)	(7,715)
Balance at End of Period		11,292	9,958	9,513
Valuation Allowance of Deferred Tax Assets
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period		21,608	26,969	27,731
Charges to Cost and Expenses		18,993	2,537	3,728
Deductions	[2]	(18,571)	(7,898)	(4,490)
Balance at End of Period		$ 22,030	$ 21,608	$ 26,969

[1] Exchange rate fluctuations.

[2] Allowance for doubtful accounts represents accounts written-off, net of recoveries and deferred tax asset valuation represents release of prior valuation allowances.