Unaudited Condensed Statements of Consolidated Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Income Statement [Abstract]
Net sales	$ 466,179	$ 331,345
Cost of goods sold	353,343	249,307
Gross profit	112,836	82,038
Selling, general and administrative expenses	78,400	44,278
Operating profit	34,436	37,760
Other income (expense):
Interest expense	(12,212)	(1,422)
Interest income	152	220
Foreign exchange gain (loss)	(5,021)	475
Other, net	(291)	(5)
Non operating income (expense), total	(17,372)	(732)
Income from continuing operations before income tax expense	17,064	37,028
Income tax expense	(5,080)	(5,746)
Income from continuing operations, net of tax	11,984	31,282
Loss from discontinued operations, net of tax	(136)	(240)
Consolidated net income	11,848	31,042
Net (income) loss attributable to the noncontrolling interests	101	(390)
Net income attributable to OM Group, Inc. common stockholders	11,949	30,652
Earnings per common share - basic:
Income from continuing operations attributable to OM Group, Inc. common stockholders (in dollars per share)	$ 0.38	$ 1.01
Loss from discontinued operations attributable to OM Group, Inc. common stockholders (per share)	$ (0.01)	$ (0.01)
Net income (loss) attributable to OM Group, Inc. common stockholders (in dollars per share)	$ 0.37	$ 1.00
Earnings per common share - assuming dilution:
Income from continuing operations attributable to OM Group, Inc. common stockholders (in dollars per share)	$ 0.38	$ 1.01
Loss from discontinued operations attributable to OM Group, Inc. common stockholders (per share)	$ (0.01)	$ (0.01)
Net income (loss) attributable to OM Group, Inc. common stockholders (in dollars per share)	$ 0.37	$ 1.00
Weighted average shares outstanding
Basic (in shares)	31,874	30,526
Assuming dilution (in shares)	32,032	30,695
Amounts attributable to OM Group, Inc. common shareholders:
Income from continuing operations, net of tax	12,085	30,892
Loss from discontinued operations, net of tax	(136)	(240)
Net income attributable to OM Group, Inc. common stockholders	$ 11,949	$ 30,652