Potential number of performance based shares to be granted

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- Definition

Restricted stock grant fair value.

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Stockholders Equity Note [Line Items]

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- Definition

Aggregate number of common shares reserved for future issuance.

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- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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- Definition

Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation.

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- Definition

The noncash expense that represents the cost of restricted stock or unit distributed to employees as compensation.

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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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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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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).

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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.

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- Definition

Number of shares issued during the period as a result of the conversion of convertible securities.

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- Definition

Amount of stock repurchase plan authorized.

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No definition available.

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Expiration date for the purchase of an entity's own shares under a stock repurchase plan, in the CCYY-MM-DD format.

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No definition available.

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Amount remaining of a stock repurchase plan authorized.

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- Definition

Number of shares that have been repurchased and retired during the period.

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Equity impact of the value of stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital).

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Equity - Additional Information (Detail) - USD ($)				12 Months Ended			60 Months Ended
Equity - Additional Information (Detail) - USD ($)	Apr. 01, 2018	Oct. 27, 2017	Sep. 30, 2017	Aug. 31, 2018	Aug. 31, 2017	Aug. 31, 2016	Aug. 31, 2018	Jan. 05, 2018
Stockholders Equity Note [Line Items]
Shares available for grant				1,050,675	233,271	476,770	1,050,675
Performance based share based compensation				317,036	269,705	447,895
Share based compensation, non vested shares				467,710			467,710
Additional shares available for grant				467,710
Unamortized compensation cost of restricted stock grants				$ 15,500,000			$ 15,500,000
2018 Senior Notes
Stockholders Equity Note [Line Items]
Conversion of 2018 Convertible Senior Notes, shares	3,400,000
Debt instrument, maturity date				Apr. 01, 2018
2017 Amended and Restated Stock Incentive Plan
Stockholders Equity Note [Line Items]
Number of shares reserved for future issuance								1,100,000
Maximum aggregate number of common shares authorized for issuance								5,425,000
Selling, Administrative and Cost of Revenue
Stockholders Equity Note [Line Items]
Restricted stock compensation expense				$ 17,200,000	$ 20,200,000	$ 22,500,000
Share Repurchase Program - 2014
Stockholders Equity Note [Line Items]
Repurchase of common stock, shares				0	0		3,206,226
Stock repurchase program total cost of repurchased shares							$ 137,000,000
Remaining authorized repurchase amount				$ 88,000,000			88,000,000
Repurchase program expiration date		Mar. 31, 2019	Jan. 01, 2018	Jan. 01, 2018
Maximum \| Share Repurchase Program - 2013
Stockholders Equity Note [Line Items]
Amount authorized for repurchase				$ 225,000,000			$ 225,000,000
Unvested Restricted Stock Grants
Stockholders Equity Note [Line Items]
Share based compensation, non vested shares				788,744	837,654		788,744
Fair value of awards granted				$ 15,200,000	$ 11,300,000	$ 12,500,000
Restricted Stock \| Minimum
Stockholders Equity Note [Line Items]
Vesting period of compensation expense				1 year
Restricted Stock \| Maximum
Stockholders Equity Note [Line Items]
Vesting period of compensation expense				3 years