Consolidated Statements Of Income And Comprehensive Income (Parenthetical) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Apr. 30, 2015	Apr. 30, 2014	Apr. 30, 2013
Income Statement [Abstract]
Tax benefits from discontinued operations	$ (8,125)	$ (15,422)	$ (19,662)
Tax effect of reclassification adjustment for gains included in income	$ (27)	$ 2,130	$ 71

Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 9

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27357-111563

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 12

-URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e640-108580

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