Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares	12 Months Ended
Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2015
Statement of Stockholders' Equity [Abstract]
Cash dividends (dollars per share)	$ 0.705	$ 0.655	$ 0.605

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

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Period Type:	duration