Restructuring Charges, Net (Narrative) (Detail) (USD $)	12 Months Ended
Apr. 30, 2012	Apr. 30, 2011	Apr. 30, 2010
Restructuring Charges, Net [Abstract]
Restructuring charges, gross			$ 25,800,000
Severance costs			16,000,000
Consolidation of premises			9,800,000
Reductions from previous restructuring charges			(5,100,000)
Restructuring costs, net	929,000	2,130,000	20,673,000
Restructuring liability included in other long-term liabilities	$ 1,400,000	$ 2,100,000
Long-term restructuring liability, payment term (in years)	7

The charge against earnings in the period, comprised of costs associated with restructuring activities not otherwise specified in the taxonomy pursuant to a duly authorized plan, excluding a discontinued operation as defined by generally accepted accounting principles. Costs of such activities include those for one-time termination benefits, termination of an operating lease or other contract, consolidating or closing facilities, and relocating employees, but excludes costs associated with the retirement of a long-lived asset and severance costs associated with established compensation plans.

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Amount charged against earnings in the period for incurred and estimated costs associated with exit from or disposal of business activities or restructurings pursuant to a duly authorized plan, excluding asset retirement obligations.

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- Definition

Carrying amount as of the balance sheet date of known and estimated costs associated with exit from or disposal of business activities or restructurings pursuant to a duly authorized plan, which are expected to be paid after one year or beyond the next operating cycle, if longer. Costs of such activities include those for one-time termination benefits, termination of an operating lease or other contract, consolidating or closing facilities, and relocating employees, and costs associated with an ongoing benefit arrangement, but excludes costs associated with the retirement of a long-lived asset.

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- Definition

Net total Increase or Decrease in the accrual for restructuring costs during the reporting period.

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- Definition

The charge against earnings in the period for known and estimated costs of termination benefits provided to current employees that are involuntarily terminated under a benefit arrangement associated with exit from or disposal of business activities or restructurings pursuant to a duly authorized plan, excluding costs or losses pertaining to an entity newly acquired in a business combination or a discontinued operation as defined by generally accepted accounting principles and costs associated with one-time termination benefits.

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

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