Business Acquisitions (Details) (USD $)	3 Months Ended								12 Months Ended				7 Months Ended	12 Months Ended						7 Months Ended		7 Months Ended		7 Months Ended		12 Months Ended
	Aug. 31, 2013	May 31, 2013	Feb. 28, 2013	Nov. 30, 2012	Aug. 31, 2012	May 31, 2012	Feb. 29, 2012	Nov. 30, 2011	Aug. 31, 2013	Aug. 31, 2012	Aug. 31, 2011	Sep. 02, 2013 ThePerriteGroup [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]	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 Intangible Assets [Member] Elian S.A.S. [Member]	Jan. 31, 2012 Customer-Related Intangible Assets [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, 2013 Maximum [Member] Customer-Related Intangible Assets [Member]	Aug. 31, 2013 Maximum [Member] Developed Technology [Member]	Aug. 31, 2013 Maximum [Member] Trademarks and Tradenames [Member]
Business Acquisitions
Purchase consideration												$ 51,300,000				$ 66,545,000	$ 15,200,000	$ 1,100,000	$ 36,800,000
Repayment of debt of acquired entity included in purchase consideration																4,300,000
Cash and cash equivalents																1,624,000
Accounts receivable																6,897,000
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	139,526,000				128,353,000				139,526,000	128,353,000	91,753,000					40,718,000
Finite-lived intangible asset, useful life																				9 years		10 years		5 years		20 years	15 years	20 years
Gross contractual amount of acquired receivables																7,300,000
Net sales	537,288,000	548,589,000	515,440,000	532,085,000	517,684,000	563,071,000	490,241,000	510,276,000	2,133,402,000	2,081,272,000	2,159,053,000		20,306,000
Income before taxes									53,732,000	66,827,000	66,139,000		640,000
Net income attributable to A. Schulman, Inc.	(2,682,000)	5,217,000	11,785,000	11,779,000	11,236,000	16,996,000	9,073,000	13,582,000	26,099,000	50,887,000	40,996,000		402,000
Inventory step up adjustments before taxes									138,000	677,000	607,000		700,000
Additional costs from fixed and intangible assets from business combination													2,300,000
Net sales														2,097,043,000	2,198,814,000
Net income attributable to A. Schulman, Inc.														$ 52,423,000	$ 43,376,000
Net income per share of common stock attributable to A. Schulman, Inc. - diluted														$ 1.77	$ 1.39