Other Noncurrent Assets And Liabilities (Details) (USD $) In Millions, unless otherwise specified	Apr. 30, 2015	Apr. 30, 2014
Other Noncurrent Assets And Liabilities [Abstract]
Obligation under deferred compensation plans	$ 33.8	$ 38.1

Aggregate carrying value as of the balance sheet date of the liabilities for all deferred compensation arrangements payable beyond one year (or the operating cycle, if longer).

No definition available.

Name:	us-gaap_DeferredCompensationLiabilityClassifiedNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant