Net (Loss) Income Per Share - Schedule of Basic and Diluted Net (Loss) Income Per Share (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended	9 Months Ended
May 31, 2020	May 31, 2019	May 31, 2020	May 31, 2019
Earnings Per Share [Abstract]
(Loss) income from continuing operations	$ (4,648)	$ 16,432	$ (6,738)	$ 46,557
Net income attributable to noncontrolling interests	(278)	(750)	(1,329)	(1,585)
(Loss) income from continuing operations attributable to SSI shareholders	(4,926)	15,682	(8,067)	44,972
(Loss) income from discontinued operations, net of tax	(69)	8	(40)	(202)
Net (loss) income attributable to SSI shareholders	$ (4,995)	$ 15,690	$ (8,107)	$ 44,770
Computation of shares:
Weighted average common shares outstanding, basic	27,724	27,510	27,653	27,548
Incremental common shares attributable to dilutive performance share awards, restricted stock units and deferred stock units		564		636
Weighted average common shares outstanding, diluted	27,724	28,074	27,653	28,184

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Amount after tax of income (loss) from continuing operations attributable to the parent.

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Amount after tax of income (loss) from continuing operations including portion attributable to the noncontrolling interest.

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Amount after tax of income (loss) from a discontinued operation including the portion attributable to the noncontrolling interest. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Amount of Net Income (Loss) attributable to noncontrolling interest.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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