Consolidated Statements Of Stockholders' Equity (Parenthetical) (USD $)	12 Months Ended
Apr. 30, 2015	Apr. 30, 2014	Apr. 30, 2013
Statement of Stockholders' Equity [Abstract]
Cash dividends declared per share	$ 0.8	$ 0.8	$ 0.80

Aggregate dividends paid during the period for each share of common stock outstanding.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Name:	us-gaap_CommonStockDividendsPerShareCashPaid
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration