Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Nov. 30, 2018	Nov. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 16,618	$ 19,221
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	(1,364)	(1,709)
Pension obligations, net	202	82
Total other comprehensive loss, net of tax	(1,162)	(1,627)
Comprehensive income	15,456	17,594
Less comprehensive income attributable to noncontrolling interests	(430)	(857)
Comprehensive income attributable to SSI	$ 15,026	$ 16,737