Benefits Expected to be Paid under Defined Benefit Pension Plans (Detail) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2012
Defined Benefit Plan Disclosure [Line Items]
2013	$ 29,472
2014	31,112
2015	32,618
2016	34,471
2017	36,315
Thereafter	201,722
Defined Benefit Plan, Expected Future Benefit Payments, Total	$ 365,710

Defined Benefit Plan, Expected Future Benefit Payments

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- Definition

Amount of benefits expected to be paid in the five fiscal years after the fifth fiscal year following the latest fiscal year from a defined benefit plan.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (f)

-URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e1928-114920

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- Definition

Amount of benefits expected to be paid in the next fiscal year following the latest fiscal year from a defined benefit plan.

+ References

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- Definition

Amount of benefits expected to be paid in the fifth fiscal year following the latest fiscal year from a defined benefit plan.

+ References

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Amount of benefits expected to be paid in the fourth fiscal year following the latest fiscal year from a defined benefit plan.

+ References

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Amount of benefits expected to be paid in the third fiscal year following the latest fiscal year from a defined benefit plan.

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Amount of benefits expected to be paid in the second fiscal year following the latest fiscal year from a defined benefit plan.

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