Goodwill And Intangible Assets (Schedule Of Inangible Assets And Goodwill) (Details) (USD $) In Thousands, unless otherwise specified						12 Months Ended
Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2011	Apr. 30, 2013 Goodwill [Member]	Apr. 30, 2012 Goodwill [Member]	Apr. 30, 2013 Customer-Related [Member]	Apr. 30, 2012 Customer-Related [Member]	Apr. 30, 2013 Technology-Based [Member]	Apr. 30, 2012 Technology-Based [Member]	Apr. 30, 2013 Trademarks [Member]	Apr. 30, 2012 Trademarks [Member]	Apr. 30, 2013 Trade Names [Member]	Apr. 30, 2012 Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill, Beginning balance	$ 11,706	$ 11,706	$ 25,161	$ 11,706	$ 11,706
Goodwill, Gross carrying amount				11,706	11,706
Goodwill, Net carrying amount	11,706	11,706	25,161	11,706	11,706
Finite-lived intangible assets, Gross carrying amount	25,280	25,280				6,236	6,236	2,638	2,638	4,600	4,600	100	100
Finite-lived intangible assets, Accumulated amortization	(6,422)	(4,884)				(3,723)	(3,043)	(1,722)	(1,410)	(877)	(331)	(100)	(100)
Finite-lived intangible assets, Net carrying amount	7,152					2,513	3,193	916	1,228	3,723	4,269
Finite-lived intangible assets, Weighted-average useful life						7 years	7 years	5 years	5 years	10 years	10 years	2 years	2 years
Intangible assets, Net carrying amount	$ 18,858	$ 20,396

Carrying amount as of the balance sheet date, which is the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable) and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions.

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 68

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

-Publisher FASB

-Name Accounting Standards Codification

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 72

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

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Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 34

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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