Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares	12 Months Ended
Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2014
Cash dividends paid, per share	$ 0.51	$ 0.47	$ 0.44
Stock options exercised, shares	84,000	29,075	97,250
Treasury stock, shares		1,159	69,773
Common Stock [Member]
Stock options exercised, shares	84,000	29,075	97,250
Additional Paid-in Capital [Member]
Stock options exercised, shares	84,000	29,075	97,250
Treasury Stock [Member]
Stock options exercised, shares	84,000	29,075	97,250
Treasury stock, shares		1,159	69,773
Retained Earnings [Member]
Cash dividends paid, per share	$ 0.51	$ 0.47	$ 0.44
Stock options exercised, shares	84,000
Accumulated Other Comprehensive Income (Loss) [Member]
Stock options exercised, shares	84,000

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)
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Reference 5: http://www.xbrl.org/2003/role/presentationRef
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