Number Of Employee Groups

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Number Of Performance Periods

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- Definition

Number Of Stock Based Compensation Plans

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Performance Period

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- Definition

Period To Achieve Cultural Goals

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Number of Plans

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- Definition

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Total of the carrying values as of the balance sheet date of obligations incurred through that date and payable for obligations related to services received from employees, such as accrued salaries and bonuses, payroll taxes and fringe benefits. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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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.

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- Definition

Unrecognized cost of unvested options awarded to employees as compensation.

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- Definition

The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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Amount of cash inflow from exercise of stock options granted under share-based compensation arrangement.

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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.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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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).

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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.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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Stock-Based Compensation (Narrative) (Details) $ in Thousands	12 Months Ended
	Apr. 30, 2018 USD ($) plan group performance_period award shares	Apr. 30, 2017 USD ($)	Apr. 30, 2016 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of employee groups \| group	1
Number of stock-based compensation plans \| award	2
Stock-based compensation expense, before income taxes	$ 3,097	$ 3,469	$ 3,609
Number of stock incentive plans \| plan	3
Shares available for awards \| shares	841,504
Contractual terms, years	2 years 1 month 6 days
Vesting period, years	3 years
Total fair value of options vested	$ 300	600	700
Cash received from options exercised	1,300	2,400	8,100
Tax benefit realized from the tax deduction from option exercises	0	1,000	4,300
Accrued compensation and related expenses	$ 48,682	36,162
Non Employee Directors [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual terms, years	4 years
Non Employee Directors [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual terms, years	10 years
Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual terms, years	10 years
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period, years	3 years
Stock Options [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual terms, years	10 years
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period, years	3 years
Total unrecognized compensation expense related to unvested stock options granted	$ 4,900
Expected to be recognized over a weighted average period	1 year 7 months 6 days
Number of performance periods \| performance_period	3
Performance period	1 year
Period to achieve cultural goals	3 years
Employee And Non Employee Director Service Based Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period, years	2 years
Performance-Based Restricted Stock Tracking Units (RSTUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares approved for grants \| shares	4,496
Service-Based Restricted Stock Tracking Units (RSTUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares approved for grants \| shares	2,519
Restricted Stock Tracking Units (RSTUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense, before income taxes	$ 400	800	$ 800
Vesting period, years	3 years
Accrued compensation and related expenses	$ 1,000	$ 1,500