Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	May 31, 2020	May 31, 2019	May 31, 2020	May 31, 2019
Income Statement [Abstract]
Revenues	$ 402,683	$ 547,396	$ 1,247,749	$ 1,584,981
Operating expense:
Cost of goods sold	356,217	474,598	1,101,497	1,379,418
Selling, general and administrative	45,544	48,575	138,744	139,483
(Income) from joint ventures	(309)	(311)	(698)	(980)
Asset impairment charges	2,227		4,321	63
Restructuring charges and other exit-related activities	2,710	75	7,810	813
Operating (loss) income	(3,706)	24,459	(3,925)	66,184
Interest expense	(2,656)	(2,294)	(5,399)	(6,267)
Other (expense) income, net	(90)	29	18	373
(Loss) income from continuing operations before income taxes	(6,452)	22,194	(9,306)	60,290
Income tax benefit (expense)	1,804	(5,762)	2,568	(13,733)
(Loss) income from continuing operations	(4,648)	16,432	(6,738)	46,557
(Loss) income from discontinued operations, net of tax	(69)	8	(40)	(202)
Net (loss) income	(4,717)	16,440	(6,778)	46,355
Net income attributable to noncontrolling interests	(278)	(750)	(1,329)	(1,585)
Net (loss) income attributable to SSI shareholders	$ (4,995)	$ 15,690	$ (8,107)	$ 44,770
Net (loss) income per share attributable to SSI shareholders Basic:
(Loss) income per share from continuing operations	$ (0.18)	$ 0.57	$ (0.29)	$ 1.63
Net (loss) income per share	(0.18)	0.57	(0.29)	1.63
Net (loss) income per share attributable to SSI shareholders Diluted:
(Loss) income per share from continuing operations	(0.18)	0.56	(0.29)	1.60
Net (loss) income per share	$ (0.18)	$ 0.56	$ (0.29)	$ 1.59
Weighted average number of common shares:
Basic	27,724	27,510	27,653	27,548
Diluted	27,724	28,074	27,653	28,184