Reconciliation of Statutory Federal Income Tax Rate to Effective Consolidated Tax Rate (Detail)	12 Months Ended
Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2011
Income Taxes [Line Items]
U.S. federal statutory income tax rate	35.00%	35.00%	35.00%
Foreign source income, net of credits generated	0.60%	3.00%	1.90%
Foreign tax rates differential	(3.70%)	(2.90%)	(3.80%)
COLI increase, net	(4.80%)	(2.70%)	(2.80%)
Repatriation of foreign earnings	(3.20%)	(1.70%)	0.10%
State income taxes, net of federal benefit	5.70%	4.00%	4.60%
Adjustments for valuation allowance	(0.40%)	(0.70%)	4.80%
Non-deductible business acquisition transaction costs	1.30%
Expense disallowances	1.10%	0.80%	0.50%
Change in uncertain tax positions	1.90%		(2.30%)
Other	1.30%	0.30%	(1.60%)
Effective income tax rate	34.80%	35.10%	36.40%

Effective Income Tax Rate Reconciliation, Transaction Costs

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A ratio calculated by dividing the reported amount of income tax expense attributable to continuing operations for the period by GAAP-basis pretax income from continuing operations.

+ References

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

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-Name Statement of Financial Accounting Standard (FAS)

-Number 109

-Paragraph 47

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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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-Publisher FASB

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-Topic 235

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-Section S99

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-Subparagraph (SX 210.4-08.(h)(2))

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The domestic federal statutory tax rate applicable under enacted tax laws to the Company's pretax income from continuing operations for the period. The "statutory" tax rate is the regular tax rate if there are alternative tax systems.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 109

-Paragraph 47

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 12

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32687-109319

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-Publisher FASB

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-Topic 740

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 6.I)

-URI http://asc.fasb.org/extlink&oid=6889476&loc=d3e330036-122817

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The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate attributable to changes in the valuation allowance for deferred tax assets.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

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-Paragraph 12

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-Publisher FASB

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-Paragraph 1

-Subparagraph (SAB TOPIC 6.I)

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The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate that can be explained by the difference between statutory income tax rates in foreign jurisdictions and the domestic federal statutory income tax rate recorded during the period.

+ References

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The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate attributable to nondeductible life insurance premiums under enacted tax laws.

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The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate attributable to nondeductible expenses under enacted tax laws, or differences in the methodologies used to determine expense amounts for financial statements prepared in accordance with generally accepted accounting principles, not otherwise listed in the existing taxonomy.

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The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate attributable to all other items not otherwise listed in the existing taxonomy.

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The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate attributable to the repatriation of foreign earnings under enacted tax laws.

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The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate that can be explained by the state and local income tax expense or benefit, net of the federal tax benefit (expense) thereon, recorded during the period.

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The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate that can be explained by foreign tax credits generated or utilized under enacted tax laws during the period.

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The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate attributable to other income tax settlements during the period not otherwise listed in the existing taxonomy.

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