Quarterly Results of Operations (Unaudited) (Details) (USD $)	3 Months Ended								9 Months Ended	12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Sep. 30, 2010	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Schedule of Selected Quarterly Financial Information [Line Items]
Net sales	$ 438,611,000	$ 415,057,000	$ 329,522,000	$ 331,345,000	$ 293,128,000	$ 297,222,000	$ 303,099,000	$ 303,197,000		$ 1,514,535,000	[1]	$ 1,196,646,000	[1]	$ 871,669,000	[1]
Gross profit	102,201,000	16,742,000	73,506,000	82,038,000	70,595,000	74,281,000	67,990,000	71,822,000		274,487,000		284,688,000		165,783,000
Amounts attributable to OM Group, Inc. common shareholders:
Income (loss) from continuing operations, net of tax	50,848,000	(68,488,000)	24,709,000	30,892,000	23,680,000	23,198,000	13,307,000	22,463,000		37,961,000		82,648,000		(19,353,000)
Income (loss) from discontinued operations, net of tax	36,000	234,000	(89,000)	(240,000)	104,000	1,003,000	(518,000)	137,000		(59,000)		726,000		1,496,000
Net income (loss) attributable to OM Group, Inc. common stockholders	50,884,000	(68,254,000)	24,620,000	30,652,000	23,784,000	24,201,000	12,789,000	22,600,000		37,902,000		83,374,000		(17,857,000)
Net Income (loss) per common share - basic
Income (loss) from continuing operations attributable to OM Group, Inc. common stockholders (per share)	$ 1.60	$ (2.18)	$ 0.81	$ 1.01	$ 0.78	$ 0.76	$ 0.44	$ 0.74		$ 1.22		$ 2.72		$ (0.64)
Income from discontinued operations attributable to OM Group, Inc. common stockholders (per share)	$ 0.00	$ 0.01	$ 0.00	$ (0.01)	$ 0.00	$ 0.03	$ (0.02)	$ 0.01		$ 0.00		$ 0.02		$ 0.05
Net income (loss) attributable to OM Group, Inc. common stockholders (per share)	$ 1.60	$ (2.17)	$ 0.81	$ 1.00	$ 0.78	$ 0.79	$ 0.42	$ 0.75		$ 1.22		$ 2.74		$ (0.59)
Net income (loss) per common share - assuming dilution
Income (loss) from continuing operations attributable to OM Group, Inc. common stockholders (per share)	$ 1.59	$ (2.18)	$ 0.80	$ 1.01	$ 0.77	$ 0.76	$ 0.43	$ 0.74		$ 1.21		$ 2.70		$ (0.64)
Income from discontinued operations attributable to OM Group, Inc. common stockholders (per share)	$ 0.00	$ 0.01	$ 0.00	$ (0.01)	$ 0.01	$ 0.03	$ (0.01)	$ 0.00		$ 0.00		$ 0.03		$ 0.05
Net income (loss) attributable to OM Group, Inc. common stockholders (per share)	$ 1.59	$ (2.17)	$ 0.80	$ 1.00	$ 0.78	$ 0.79	$ 0.42	$ 0.74		$ 1.21		$ 2.73		$ (0.59)
Gain on sale of land		9,693,000								9,693,000		0		0
Discrete tax benefit (expense)					1,500,000	300,000	(5,200,000)	2,800,000		7,400,000		(5,400,000)		(10,200,000)
Restructuring charges	17,900,000	104,700,000	4,000,000							500,000		2,100,000		12,700,000
Income tax (expense) benefit	2,100,000								(31,800,000)	17,796,000		(29,656,000)		(20,899,000)
Effective income tax rate									37.10%			27.60%
GTL Joint Venture [Member]
Net income (loss) per common share - assuming dilution
Discrete tax benefit (expense)		$ 3,400,000

[1] Net sales attributed to the geographic area are based on the location of the manufacturing facility, except for Japan, which is a sales office.