Amended Shares Reserved for Issuance.

No definition available.

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- Definition

The amount per a share that the employees paid for the shares purchased through the ESPP.

+ References

No definition available.

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- Definition

Full Value Stock to Stock Options Ratio

+ References

No definition available.

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- Definition

Original Shares Reserved for Issuance.

+ References

No definition available.

+ Details

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- Definition

Share-based compensation arrangement by share-based payment award, maximum employee subscription value.

+ References

No definition available.

+ Details

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- Definition

Unrecognized cost of unvested share-based compensation awards.

+ References

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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- Definition

The cash inflow associated with the amount received from holders exercising their stock options. This item inherently excludes any excess tax benefit, which the entity may have realized and reported separately.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (j)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 14

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3255-108585

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- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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- Definition

Discount rate from fair value on purchase date that participants pay for shares.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

+ Details

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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

+ References

+ Details

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- Definition

Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 14.D.2)

-URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (f)(2)(i)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 14

-Section D

-Subsection 2

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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

+ References

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

+ References

+ Details

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- Definition

The highest percentage of annual salary that an employee is permitted to utilize with respect to the plan.

+ References

+ Details

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- Definition

Number of equity instruments other than options outstanding, including both vested and non-vested instruments.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(i)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

+ References

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- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

+ References

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- Definition

Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

+ References

+ Details

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Period Type:	instant

- Definition

Net number of share options (or share units) granted during the period.

+ References

+ Details

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- Definition

Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

+ References

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- Definition

Number of shares issued during the period as a result of an employee stock purchase plan.

+ References

+ Details

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- Definition

Number of share options (or share units) exercised during the current period.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.28,29)

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iv)(2)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

-Article 5

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- Definition

Number of shares that have been repurchased during the period and are being held in treasury.

+ References

+ Details

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- Definition

Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

+ References

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Employee Stock Plans - Additional Information (Detail) (USD $)	12 Months Ended
	Apr. 30, 2014	Apr. 30, 2013	Apr. 30, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value of options outstanding	$ 5,100,000
Aggregate intrinsic value of options exercisable	4,400,000
Common stock repurchased, value	2,249,000	2,838,000	4,215,000
Cash proceeds from exercise of stock options	8,800,000	2,100,000	2,900,000
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares repurchased during the period	113,000	197,000	190,000
Common stock repurchased, value	2,249,000	2,838,000	4,215,000
Stock issued for stock options exercised	654,458	237,856	228,835
Time Based Restricted Stock \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Time Based Restricted Stock \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Market Based Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Total unrecognized compensation cost related to non-vested awards	2,100,000
Shares outstanding	300,000
Performance Based Restricted Stock Unit
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Total unrecognized compensation cost related to non-vested awards	4,300,000
Shares outstanding	200,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility			47.07%
Risk-free interest rate			1.47%
Expected option life (in years)			5 years
Expected dividend yield			0.00%
Stock option grants	0	0	48,000
Total unrecognized compensation cost related to non-vested awards	200,000
Stock issued for stock options exercised	655,000	238,000	235,000
Stock Options \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Expiration period	7 years
Stock Options \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Expiration period	10 years
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost related to non-vested awards	22,200,000
Expected cost recognized over weighted-average period	2 years 3 months 18 days
Shares repurchased during the period	112,792	197,456
Common stock repurchased, value	2,200,000	2,800,000
Stock Incentive Plan 2008
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock incentive plan, maximum number of shares issuable	5,700,000
Issuance of full-value stock awards limitation, required ratio to stock options	1.91
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized payroll deductions	15.00%
Authorized payroll deductions, value	$ 25,000
Fair market price of common stock	85.00%
Employees stock purchased			76,909
Employees stock purchased, per share value			$ 18.69
Shares reserved for issuance	1,500,000
Amended shares reserved for issuance	3,000,000
Shares available for future issuance	1,600,000