Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance at January 1, 2013	$ (88,005)
Other comprehensive income (loss) before reclassifications	(29,827)
Amounts reclassified from accumulated other comprehensive (income) loss	4,585
Net change in accumulated other comprehensive income (loss)	(25,242)	32,447
Ending balance at March 31, 2013	(113,247)
Foreign exchange gain (loss)	(2,344)	(5,021)
Loss on divestiture of Advanced Materials business	(111,546)	0
Income from continuing operations, net of tax	(111,389)	11,984
Tax (expense) or benefit	2,581	5,080
Net income attributable to OM Group, Inc. common stockholders	(109,713)	11,949
Foreign Currency Translation Loss
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance at January 1, 2013	(21,299)
Other comprehensive income (loss) before reclassifications	(29,950)
Amounts reclassified from accumulated other comprehensive (income) loss	4,585
Net change in accumulated other comprehensive income (loss)	(25,365)
Ending balance at March 31, 2013	(46,664)
Unrealized Gains and Losses on Cash Flow Hedging Derivatives
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance at January 1, 2013	(84)
Other comprehensive income (loss) before reclassifications	20
Amounts reclassified from accumulated other comprehensive (income) loss	0
Net change in accumulated other comprehensive income (loss)	20
Ending balance at March 31, 2013	(64)
Pension and Post-Retirement Obligation
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance at January 1, 2013	(66,622)
Other comprehensive income (loss) before reclassifications	103
Amounts reclassified from accumulated other comprehensive (income) loss	0
Net change in accumulated other comprehensive income (loss)	103
Ending balance at March 31, 2013	(66,519)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Loss on Divestiture [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Loss on divestiture of Advanced Materials business	(4,450)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Foreign Currency Translation Loss
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Foreign exchange gain (loss)	(135)
Income from continuing operations, net of tax	(4,585)
Tax (expense) or benefit	0
Net income attributable to OM Group, Inc. common stockholders	$ (4,585)