Unaudited Condensed Statements of Consolidated Total Equity (USD $) In Thousands	Total	Stock Options and Restricted Stock Awards [Member]	Non-Employee Directors [Member]	Noncontrolling Interests [Member]	OM Group Inc. Stockholders' Equity [Member]	Common Stock [Member]	Capital in Excess of Par Value [Member]	Capital in Excess of Par Value [Member] Stock Options and Restricted Stock Awards [Member]	Capital in Excess of Par Value [Member] Non-Employee Directors [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning balance at Dec. 31, 2010				$ 39,834		$ 307	$ 578,948			$ 667,882	$ (7,234)	$ (3,119)
Beginning balance, shares at Dec. 31, 2010						30,523
Shares issued under share-based compensation plans, shares						21
Shares issued under share-based compensation plans						0
Stock option exercises							157
Share-based compensation		3,368	155					3,368	155
Net income (loss) attributable to OM Group, Inc.	55,272									55,272
Reacquired shares											(193)
Foreign currency translation	11,295											11,295
Reclassification of hedging activities into earnings, net of tax												(373)
Unrealized gain on cash flow hedges, net of tax												496
Pension	(200)											(200)
Net income (loss) attributable to the noncontrolling interest	1,482			1,482
Foreign currency translation				4
Ending balance at Jun. 30, 2011	1,348,481			41,320	1,307,161	307	582,628			723,154	(7,427)	8,499
Ending balance, shares at Jun. 30, 2011						30,544
Beginning balance at Mar. 31, 2011
Share-based compensation		1,363	80
Net income (loss) attributable to OM Group, Inc.	24,620
Foreign currency translation	6,331
Pension	(100)
Net income (loss) attributable to the noncontrolling interest	1,092
Ending balance at Jun. 30, 2011	1,348,481				1,307,161
Beginning balance at Dec. 31, 2011	1,275,294			44,501		320	625,515			705,784	(7,427)	(93,399)
Beginning balance, shares at Dec. 31, 2011						31,865
Shares issued under share-based compensation plans, shares						27
Shares issued under share-based compensation plans						1
Stock option exercises							0
Share-based compensation		3,558	263					3,558	263
Net income (loss) attributable to OM Group, Inc.	(10,390)									(10,390)
Reacquired shares											(254)
Foreign currency translation	(14,846)											(14,846)
Reclassification of hedging activities into earnings, net of tax												(1,780)
Unrealized gain on cash flow hedges, net of tax												2,918
Pension	(404)											(404)
Net income (loss) attributable to the noncontrolling interest	(345)			(345)
Foreign currency translation				(2)
Ending balance at Jun. 30, 2012	1,254,821			44,154	1,210,667	321	629,336			695,394	(7,681)	(106,703)
Ending balance, shares at Jun. 30, 2012						31,892
Beginning balance at Mar. 31, 2012
Share-based compensation		1,282	132
Net income (loss) attributable to OM Group, Inc.	(22,339)									(22,339)
Foreign currency translation	(44,208)
Pension	(202)
Net income (loss) attributable to the noncontrolling interest	(244)
Ending balance at Jun. 30, 2012	$ 1,254,821				$ 1,210,667					$ 695,394