Business Acquisitions (Details) (USD $)	3 Months Ended								12 Months Ended				7 Months Ended	12 Months Ended			4 Months Ended	12 Months Ended					7 Months Ended		7 Months Ended		7 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	Mar. 01, 2010 McCann Color Inc. [Member]	Aug. 31, 2012 Elian S.A.S. [Member]	Aug. 31, 2012 Elian S.A.S. [Member]	Aug. 31, 2011 Elian S.A.S. [Member]	Jan. 31, 2012 Elian S.A.S. [Member]	Aug. 31, 2010 ICO Inc. [Member]	Aug. 31, 2010 ICO Inc. [Member]	Apr. 30, 2010 ICO Inc. [Member]	Nov. 03, 2010 Mash Industria e Comercio de Compostos Plasticos L.T.D.A. [Member]	Jun. 30, 2011 Surplast S.A. [Member]	Sep. 04, 2012 E.C.M. Plastics Inc. [Member]	Aug. 31, 2012 Customer Related Intangibles [Member] Elian S.A.S. [Member]	Jan. 31, 2012 Customer Related Intangibles [Member] Elian S.A.S. [Member]	Aug. 31, 2012 Developed Technology [Member] Elian S.A.S. [Member]	Jan. 31, 2012 Developed Technology [Member] Elian S.A.S. [Member]	Aug. 31, 2012 Trademarks and Tradenames [Member] Elian S.A.S. [Member]	Jan. 31, 2012 Trademarks and Tradenames [Member] Elian S.A.S. [Member]	Aug. 31, 2012 Maximum [Member] Customer Related Intangibles [Member]	Aug. 31, 2012 Maximum [Member] Developed Technology [Member]	Aug. 31, 2012 Maximum [Member] Trademarks and Tradenames [Member]
Business Acquisitions
Purchase consideration												$ 8,800,000				$ 66,500,000			$ 237,700,000	$ 15,200,000	$ 1,100,000	$ 36,500,000
Repayment of debt of acquired entity included in purchase consideration																4,300,000
Cash and cash equivalents																1,624,000
Accounts receivable																6,900,000
Inventories																3,427,000
Prepaid expenses and other current assets																434,000
Property, plant and equipment																5,111,000
Intangible assets																27,779,000								18,300,000		8,600,000		900,000
Other long-term assets																20,000
Total assets acquired																45,292,000
Accounts payable																4,907,000
Other accrued liabilities																3,106,000
Deferred income taxes																10,598,000
Pension plans																711,000
Other long-term liabilities																143,000
Total liabilities assumed																19,465,000
Net identifiable assets acquired																25,827,000
Goodwill																40,718,000
Net assets acquired																66,545,000
Finite-lived intangible asset, useful life																							9 years		10 years		5 years		19 years	15 years	20 years
Gross contractual amount of acquired receivables																7,300,000
Net sales	524,446,000	569,107,000	495,911,000	517,289,000	578,087,000	611,142,000	508,343,000	495,383,000	2,106,753,000	2,192,955,000	1,590,443,000		20,306,000				134,166,000
Income before taxes									65,968,000	57,467,000	39,931,000		640,000				(2,030,000)
Net income attributable to A. Schulman, Inc.	11,236,000	16,996,000	9,073,000	13,582,000	5,858,000	18,754,000	7,141,000	9,243,000	50,887,000	40,996,000	43,890,000		402,000				(1,163,000)
Depreciation and amortization before taxes									38,784,000	40,274,000	27,449,000		2,300,000				9,600,000
Inventory step up adjustments before taxes									677,000	607,000	3,942,000		700,000				3,900,000
Additional costs from fixed and intangible assets from business combination																	3,400,000
Net sales														2,122,525,000	2,232,715,000			1,828,339,000
Net income attributable to A. Schulman, Inc.														$ 52,423,000	$ 43,376,000			$ 45,948,000
Net income per share of common stock attributable to A. Schulman, Inc. - diluted														$ 1.77	$ 1.39			$ 1.47