Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Feb. 28, 2019	Feb. 28, 2018	Feb. 28, 2019	Feb. 28, 2018
Income Statement [Abstract]
Revenues		$ 473,565	$ 559,443	$ 1,037,585	$ 1,042,722
Operating expense:
Cost of goods sold		414,688	472,462	904,820	878,713
Selling, general and administrative		39,489	53,638	90,908	104,681
(Income) from joint ventures		(184)	(106)	(669)	(556)
Asset impairment charges (recoveries), net		0	0	63	(88)
Restructuring charges and other exit-related activities		536	91	738	191
Operating income		19,036	33,358	41,725	59,781
Interest expense		(2,067)	(2,281)	(3,973)	(4,340)
Other income, net		321	101	344	950
Income from continuing operations before income taxes		17,290	31,178	38,096	56,391
Income tax (expense) benefit		(3,855)	10,577	(7,971)	4,620
Income from continuing operations		13,435	41,755	30,125	61,011
Income (loss) from discontinued operations, net of tax		(138)	164	(210)	129
Net income		13,297	41,919	29,915	61,140
Net income attributable to noncontrolling interests		(405)	(903)	(835)	(1,760)
Net income attributable to SSI		$ 12,892	$ 41,016	$ 29,080	$ 59,380
Net income per share attributable to SSI Basic:
Income per share from continuing operations attributable to SSI (in dollars per share)		$ 0.47	$ 1.47	$ 1.06	$ 2.14
Loss per share from discontinued operations attributable to SSI (in dollars per share)		0	0.01	(0.01)	0
Net income per share attributable to SSI (in dollars per share)		0.47	1.48	1.05	2.14
Net income per share attributable to SSI Diluted:
Income per share from continuing operations attributable to SSI (in dollars per share)		0.46	1.42	1.04	2.06
Loss per share from discontinued operations attributable to SSI (in dollars per share)		0	0.01	(0.01)	0
Net income per share attributable to SSI (in dollars per share)	[1]	$ 0.46	$ 1.42	$ 1.03	$ 2.07
Weighted average number of common shares:
Basic (shares)		27,630	27,797	27,568	27,745
Diluted (Shares)		28,114	28,805	28,239	28,737
Dividends declared per common share (in dollars per share)		$ 0.1875	$ 0.1875	$ 0.3750	$ 0.3750

[1] May not foot due to rounding.