Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	May 31, 2023	May 31, 2022	May 31, 2023	May 31, 2022
Income Statement [Abstract]
Revenues	$ 809,610	$ 1,010,087	$ 2,164,293	$ 2,591,403
Operating expense:
Cost of goods sold	713,685	834,375	1,946,633	2,188,158
Selling, general and administrative	68,527	77,672	196,712	194,020
(Income) from joint ventures	(285)	(762)	(1,386)	(1,589)
Asset impairment charges		932		932
Restructuring charges and other exit-related activities	169	26	2,589	52
Operating income	27,514	97,844	19,745	209,830
Interest expense	(5,146)	(2,223)	(13,378)	(5,496)
Other loss, net	(1,306)	(34)	(5,289)	(136)
Income from continuing operations before income taxes	21,062	95,587	1,078	204,198
Income tax expense	(7,221)	(20,037)	(676)	(43,207)
Income from continuing operations	13,841	75,550	402	160,991
Loss from discontinued operations, net of tax	(233)	(46)	(78)	(46)
Net income	13,608	75,504	324	160,945
Net income attributable to noncontrolling interests	(148)	(870)	(299)	(2,497)
Net income attributable to SSI shareholders	$ 13,460	$ 74,634	$ 25	$ 158,448
Net income per share attributable to SSI shareholders Basic:
Income per share from continuing operations	$ 0.49	$ 2.65		$ 5.63
Net income per share	0.48	2.65		5.63
Net income per share attributable to SSI shareholders Diluted:
Income per share from continuing operations	0.48	2.52		5.33
Net income per share	$ 0.47	$ 2.52		$ 5.33
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Basic	28,114	28,143	27,980	28,161
Diluted	28,659	29,625	28,646	29,741