Net Income (Loss) Per Share (Details) (USD $) In Thousands, except Share data	3 Months Ended								12 Months Ended
	Aug. 31, 2011	May 31, 2011	Feb. 28, 2011	Nov. 30, 2010	Aug. 31, 2010	May 31, 2010	Feb. 28, 2010	Nov. 30, 2009	Aug. 31, 2011	Aug. 31, 2010	Aug. 31, 2009
Earnings Per Share Basic And Diluted By Common Class [Line Items]
Income (loss) from continuing operations									$ 123,637	$ 84,508	$ (27,149)
Net Income attributable to noncontrolling interest									(5,181)	(3,926)	(866)
Income (loss) from continuing operations attributable to SSI									118,456	80,582	(28,015)
Loss from discontinued operations, net of tax	(417)	282	11	23	1,191	23	(72)	(14,974)	(101)	(13,832)	(4,214)
Net income (loss) attributable to SSI	$ 36,708	$ 33,028	$ 30,825	$ 17,794	$ 17,407	$ 40,453	$ 17,459	$ (8,569)	$ 118,355	$ 66,750	$ (32,229)
Computation of shares:
Weighted average common shares outstanding, basic									27,649,000	27,832,000	28,159,000
Incremental common shares attributable to dilutive stock options, performance share awards, DSUs and RSUs									310,000	315,000
Weighted average common shares outstanding, diluted									27,959,000	28,147,000	28,159,000
Antidilutive securities excluded from computation of earnings per share									39,820	50,702	828,869