Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2019	Aug. 31, 2018	Aug. 31, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 58,322	$ 159,789	$ 46,978
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	(1,560)	(2,301)	2,711
Pension obligations, net	34	357	2,111
Total other comprehensive (loss) income, net of tax	(1,526)	(1,944)	4,822
Comprehensive income	56,796	157,845	51,800
Less comprehensive income attributable to noncontrolling interests	(1,977)	(3,338)	(2,467)
Comprehensive income attributable to SSI shareholders	$ 54,819	$ 154,507	$ 49,333