Quarterly Financial Highlights (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Aug. 31, 2012		May 31, 2012		Feb. 29, 2012		Nov. 30, 2011		Aug. 31, 2011		May 31, 2011		Feb. 28, 2011		Nov. 30, 2010		Aug. 31, 2012		Aug. 31, 2011		Aug. 31, 2010
Net sales	$ 524,446		$ 569,107		$ 495,911		$ 517,289		$ 578,087		$ 611,142		$ 508,343		$ 495,383		$ 2,106,753		$ 2,192,955		$ 1,590,443
Gross profit	66,783		76,589		64,549		69,496		71,045		78,888		66,612		69,001		277,417		285,546		232,868
Net income	11,548		17,248		9,290		13,963		6,106		18,924		7,279		9,376		52,049		41,685		44,111
Noncontrolling interests	(312)		(252)		(217)		(381)		(248)		(170)		(138)		(133)		(1,162)		(689)		(221)
Net income attributable to A. Schulman, Inc.	11,236		16,996		9,073		13,582		5,858		18,754		7,141		9,243		50,887		40,996		43,890
Earnings per share of common stock attributable to A. Schulman, Inc. — Basic:	$ 0.38		$ 0.58		$ 0.31		$ 0.46		$ 0.19		$ 0.61		$ 0.23		$ 0.29		$ 1.73		$ 1.32		$ 1.58
Earnings per share of common stock attributable to A. Schulman, Inc. — Diluted:	$ 0.38		$ 0.57		$ 0.31		$ 0.46		$ 0.19	[1]	$ 0.60	[1]	$ 0.23	[1]	$ 0.29	[1]	$ 1.72		$ 1.32	[1]	$ 1.57
Asset write-downs	613	[2]	1,917	[2]	0	[2]	0	[2]	6,225	[3]	125	[3]	1,800	[3]	0	[3]	2,530	[2]	8,150	[3]
Costs related to acquisitions	359	[4]	147	[4]	615	[4]	190	[4]	552	[5]	(356)	[5]	314	[5]	881	[5]	1,311	[4]	1,391	[5]
Restructuring related costs	1,767	[6]	1,556	[6]	1,068	[6]	2,280	[6]	2,288	[7]	1,748	[7]	2,769	[7]	438	[7]	6,671	[6]	7,243	[7]
Inventory step-up	0	[8]	53	[8]	398	[8]	0	[8]	112		0		106		78		451	[8]	296
Tax charges (benefits)	100	[9]	(260)	[9]	40	[9]	(747)	[9]	0		0		0		(65)		(867)	[9]	(65)
Total	$ 2,839		$ 3,413		$ 2,121		$ 1,723		$ 9,177		$ 1,517		$ 4,989		$ 1,332		$ 10,096		$ 17,015

[1] The sum of the four quarters does not equal the earnings per share amount calculated for the year due to rounding.

[2] Asset write-downs include charges primarily related to the write-down of the facility in Verolanuova, Italy during the third quarter of fiscal 2012 and the facility in Nashville, Tennessee during the fourth quarter of fiscal 2012. Refer to Note 16 for further discussion.

[3] Asset write-downs primarily relates to the closure of the Company's Nashville, Tennessee facility in the fourth quarter of fiscal 2011 and the closure of the Polybatch Color Center in Sharon Center, Ohio primarily in the second quarter of fiscal 2011. Refer to Note 16 for further discussion.

[4] Costs related to acquisitions include professional, legal and other expenses associated with the acquisitions of Elian, ECM and other potential acquisitions.

[5] Costs related to acquisitions include professional, legal and other expenses associated with the acquisitions of ICO, Mash, Surplast and other potential acquisitions.

[6] Restructuring includes charges related to the EMEA operations and back-office plan, the Masterbatch reorganization plan, the Americas engineered plastics plan, and the Italy plan. Refer to Note 15 for further discussion.

[7] Restructuring includes charges related to the Australia and Italy plans, the Americas engineered plastics plan, the ICO merger plan and the North America masterbatch fiscal 2010 plan. Refer to Note 15 for further discussion.

[8] Inventory step-up relates to the Elian SAS acquisition.

[9] Tax charges (benefits) include the effect of the adjustment to the Italian valuation allowance in fiscal 2012.