Contingencies and Commitments (Details) - Civil lawsuit - Verdict received $ in Millions	12 Months Ended
Apr. 30, 2016 USD ($)
Contingencies and Commitments
Litigation expense, excluding internal and external legal fees	$ 5.5
Accrued expenses and other current liabilities
Contingencies and Commitments
Accrual recorded on the balance sheet	$ 5.5

Amount charged against operating income increasing loss contingency liability, after adjustments to reduce previously estimated charges.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration