Changes in Equity and Comprehensive Income (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Nov. 30, 2011		Nov. 30, 2010
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period	$ 1,101,236		$ 979,632
Net income	7,745		18,917
Net income	7,952	[1]
Components of other comprehensive income (loss), net of tax:
Foreign currency translation adjustment (net of tax of $(468) and $371)	(6,815)	[2]	660
Pension obligations, net (net of tax of $39 and $54)	67		86
Change in net unrealized gain on cash flow hedges (net of tax of $66)			117
Comprehensive income	1,204		19,780
Distributions to noncontrolling interests	(1,477)		(631)
Share repurchases	(3,117)
Restricted stock withheld for taxes	(840)		(1,873)
Stock options exercised			16
Share-based compensation expense	5,210		3,568
Excess tax benefit (deficiency) from stock options exercised and restricted stock units vested	413		(383)
Cash dividends ($0.017 per share)	(463)		(467)
End of period	1,102,166		999,642
Other Disclosures [Abstract]
Foreign currency translation adjustment, tax	(468)		371
Pension obligations, tax	39		54
Change in net unrealized gain on cash flow hedges, tax	0		66
Cash dividends (dollars per share)	$ 0.017		$ 0.017
Net Income (Loss) Attributable to Redeemable Noncontrolling Interest	(207)
Foreign Currency Translation Adjustments Relating To Redeemable Noncontrolling Interests	(886)
SSI shareholders' equity [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period	1,094,712		975,326
Net income			17,794
Net income	7,018	[1]
Components of other comprehensive income (loss), net of tax:
Foreign currency translation adjustment (net of tax of $(468) and $371)	(6,815)	[2]	660
Pension obligations, net (net of tax of $39 and $54)	67		86
Change in net unrealized gain on cash flow hedges (net of tax of $66)			117
Comprehensive income	270		18,657
Distributions to noncontrolling interests
Share repurchases	(3,117)
Restricted stock withheld for taxes	(840)		(1,873)
Stock options exercised			16
Share-based compensation expense	5,210		3,568
Excess tax benefit (deficiency) from stock options exercised and restricted stock units vested	413		(383)
Cash dividends ($0.017 per share)	(463)		(467)
End of period	1,096,185		994,844
Noncontrolling Interest [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning of period	6,524		4,306
Net income			1,123
Net income	934	[1]
Components of other comprehensive income (loss), net of tax:
Foreign currency translation adjustment (net of tax of $(468) and $371)
Pension obligations, net (net of tax of $39 and $54)
Change in net unrealized gain on cash flow hedges (net of tax of $66)
Comprehensive income	934		1,123
Distributions to noncontrolling interests	(1,477)		(631)
Share repurchases
Restricted stock withheld for taxes
Stock options exercised
Share-based compensation expense
Excess tax benefit (deficiency) from stock options exercised and restricted stock units vested
Cash dividends ($0.017 per share)
End of period	$ 5,981		$ 4,798

[1] Net income attributable to noncontrolling interests at November 30, 2011 excludes a loss of $207 thousand allocable to the redeemable noncontrolling interest, which is reported in the mezzanine section of the Unaudited Condensed Consolidated Balance Sheets at November 30, 2011. See Note 7 - Redeemable Noncontrolling Interest.

[2] Foreign currency translation adjustments exclude $(886) thousand relating to redeemable noncontrolling interests for the three months ended November 30, 2011, which is reported in the mezzanine section of the Unaudited Condensed Consolidated Balance Sheets at November 30, 2011. See Note 7 - Redeemable Noncontrolling Interest.