Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Aug. 31, 2021	Aug. 31, 2020	Aug. 31, 2019
Income Statement [Abstract]
Revenues	$ 2,758,551	$ 1,712,343	$ 2,132,781
Operating expense:
Cost of goods sold	2,305,357	1,503,725	1,858,535
Selling, general and administrative	242,463	187,876	191,405
(Income) from joint ventures	(4,006)	(834)	(1,452)
Asset impairment charges, net		5,729	63
Restructuring charges and other exit-related activities	1,008	8,993	365
Operating income	213,729	6,854	83,865
Interest expense	(5,285)	(8,669)	(8,266)
Other (expense) income, net	(455)	(124)	641
Income (loss) from continuing operations before income taxes	207,989	(1,939)	76,240
Income tax expense	37,935	166	17,670
Income (loss) from continuing operations	170,054	(2,105)	58,570
Loss from discontinued operations, net of tax	(79)	(95)	(248)
Net income (loss)	169,975	(2,200)	58,322
Net income attributable to noncontrolling interests	(4,863)	(1,945)	(1,977)
Net income (loss) attributable to SSI shareholders	$ 165,112	$ (4,145)	$ 56,345
Net (loss) income per share attributable to SSI shareholders Basic:
Income (loss) per share from continuing operations	$ 5.90	$ (0.15)	$ 2.06
Net income (loss) per share	5.90	(0.15)	2.05
Net (loss) income per share attributable to SSI shareholders Diluted:
Income (loss) per share from continuing operations	5.66	(0.15)	2.01
Net income (loss) per share	$ 5.66	$ (0.15)	$ 2.00
Weighted average number of common shares:
Basic	27,982	27,672	27,527
Diluted	29,193	27,672	28,222