Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (Recurring [Member], USD $) In Thousands, unless otherwise specified	Apr. 30, 2015
Assets:
Foreign currency forward contracts	$ 5,506
Total assets at fair value	5,506
Liabilities:
Deferred compensation plans	9,945
Foreign currency forward contracts	2,493
Total liabilities at fair value	12,438
Level 1 [Member]
Liabilities:
Deferred compensation plans	9,945
Total liabilities at fair value	9,945
Level 2 [Member]
Assets:
Foreign currency forward contracts	5,506
Total assets at fair value	5,506
Liabilities:
Foreign currency forward contracts	2,493
Total liabilities at fair value	$ 2,493