Om 10-K 2 Mar 15 2014 FY Annual report Financial data

Document_And_Entity_Informatio

Document And Entity Information (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Feb. 27, 2015	Jun. 30, 2014
Document And Entity Information [Abstract]
Entity Registrant Name	OM GROUP INC
Entity Central Index Key	899723
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding		30,240,512
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$1,010.60

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Current assets
Cash and cash equivalents	$91.70	$118.40
Accounts receivable, less allowance of $2.5 in 2014 and $3.9 in 2013	134.5	150.7
Inventories	228.4	240.9
Other current assets	21.5	32.3
Total current assets	476.1	542.3
Property, plant and equipment, net	308.3	345.6
Goodwill	252.6	432.7
Intangible assets, net	324.8	403
Other non-current assets	57.7	59.5
Total assets	1,419.50	1,783.10
Current liabilities
Revolving credit facility	12.5	0
Accounts payable	74.7	93.6
Accrued income taxes	5.6	4.2
Accrued employee costs	34.9	36.2
Purchase price of VAC payable to seller	46.2	52.5
Other current liabilities	51.8	59.2
Total current liabilities	225.7	245.7
Deferred income taxes	74.8	102.5
Pension liabilities	244.4	220.5
Purchase price of VAC payable to seller	0	11.3
Other non-current liabilities	37.7	43.3
Stockholders’ equity:
Preferred stock, $.01 par value: Authorized 2,000,000 shares, no shares issued or outstanding	0	0
Common stock, $.01 par value: Authorized 90,000,000 shares; 32,408,222 shares issued in 2014 and 32,304,490 shares issued in 2013	0.3	0.3
Capital in excess of par value	647.3	639.8
Retained earnings	405.3	587.2
Treasury stock (2,136,116 shares in 2014 and 825,956 shares in 2013, at cost)	-58.2	-22.3
Accumulated other comprehensive loss	-157.8	-45.2
Total stockholders' equity	836.9	1,159.80
Total liabilities and stockholders' equity	$1,419.50	$1,783.10

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, except Share data, unless otherwise specified
Assets, Current [Abstract]
Allowance for doubtful accounts receivable	$2.50	$3.90
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Preferred Stock, par value (per share)	$0.01	$0.01
Preferred Stock, shares authorized (in shares)	2,000,000	2,000,000
Preferred Stock, shares issued (in shares)	0	0
Preferred Stock, shares outstanding (in shares)	0	0
Common Stock, par value (per share)	$0.01	$0.01
Common Stock, shares authorized (in shares)	90,000,000	90,000,000
Common Stock, shares issued (in shares)	32,408,222	32,304,490
Treasury Shares (in shares)	2,136,116	825,956

Statements_of_Consolidated_Ope

Statements of Consolidated Operations (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Income Statement [Abstract]
Net sales	$1,067.50	[1],[2]	$1,157.50	[1],[2]	$1,544.40	[1],[2]
Cost of goods sold	829.3		899.1		1,300.80
Gross profit	238.2		258.4		243.6
Selling, general and administrative expenses	207.9		217.3		251.2
Goodwill and intangible asset impairment	195.4		0		0
Gain on sale of property	0		0		-2.9
Operating profit (loss)	-165.1		41.1		-4.7
Other income (expense):
Interest expense	-2.6		-12.3		-49.7
Foreign exchange gain (loss)	-6.5		8		-0.8
Gain (loss) on divestiture of Advance Materials business	1.7		-111.6		0
Other, net	-0.3		12		6.6
Non operating income (expense), total	-7.7		-103.9		-43.9
Loss from continuing operations before income tax expense	-172.8		-62.8		-48.6
Income tax expense (benefit)	-0.5		10.7		-3.2
Loss from continuing operations, net of tax	-172.3		-73.5		-45.4
Loss from discontinued operations, net of tax	-0.3		-12.3		-0.4
Consolidated net loss	-172.6		-85.8		-45.8
Net loss attributable to noncontrolling interests	0		1.8		7.1
Loss attributable to OM Group, Inc. common stockholders	-172.6		-84		-38.7
Earnings per common share — basic:
Loss from continuing operations attributable to OM Group, Inc. common stockholders (in dollars per share)	($5.54)		($2.27)		($1.21)
Loss from discontinued operations attributable to OM Group, Inc. common stockholders (in dollars per share)	($0.01)		($0.39)		($0.01)
Net loss attributable to OM Group, Inc. common stockholders (in dollars per share)	($5.55)		($2.66)		($1.22)
Earnings per common share — assuming dilution:
Loss from continuing operations attributable to OM Group, Inc. common stockholders (in dollars per share)	($5.54)		($2.27)		($1.21)
Loss from discontinued operations attributable to OM Group, Inc. common stockholders (in dollars per share)	($0.01)		($0.39)		($0.01)
Loss attributable to OM Group, Inc. common stockholders (in dollars per share)	($5.55)		($2.66)		($1.22)
Weighted average shares outstanding
Basic (in shares)	31.1		31.6		31.9
Assuming dilution (in shares)	31.1		31.6		31.9
Dividends declared per common share (in dollars per share)	$0.30		$0		$0
Amounts attributable to OM Group, Inc. common stockholders:
Loss from continuing operations, net of tax	-172.3		-71.7		-38.3
Loss from discontinued operations, net of tax	-0.3		-12.3		-0.4
Loss attributable to OM Group, Inc. common stockholders	($172.60)		($84)		($38.70)
[1]	Net sales attributed to the geographic area are based on the location of the manufacturing facility, except for Japan, which was a sales office and included in the divestiture of the Advance Materials business.
[2]	All results and balances related to the UPC business are excluded for all periods presented.

Statements_of_Consolidated_Com

Statements of Consolidated Comprehensive Loss (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Consolidated net loss	($172.60)	($85.80)	($45.80)
Foreign currency translation adjustments	-81.7	25	20.7
Reclassification of hedging activities into earnings, net of tax	0.2	0.2	-1.9
Unrealized (loss) gain on cash flow hedges, net of tax	0	-0.3	5.9
Pension and post-retirement obligation, net of tax	-31.1	17.9	-19.3
Net change in accumulated other comprehensive income (loss)	-112.6	42.8	5.4
Comprehensive loss	-285.2	-43	-40.4
Comprehensive loss attributable to noncontrolling interests	0	1.8	7.1
Comprehensive loss attributable to OM Group, Inc.	($285.20)	($41.20)	($33.30)

Statements_of_Consolidated_Cas

Statements of Consolidated Cash Flows (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating activities
Consolidated net loss	($172.60)	($85.80)	($45.80)
Adjustments to reconcile consolidated net loss to net cash provided by operating activities:
Loss from discontinued operations	0.3	12.3	0.4
Depreciation and amortization	67.5	73.9	84.3
Goodwill and intangible asset impairment charges	195.4	0	0
Share-based compensation expense	7.6	6.2	5.8
Foreign exchange loss (gain)	6.5	-8	0.8
Deferred income tax benefit	-17.2	-7.3	-30.2
VAC lower of cost or market (LCM) charges	0	0	78.4
(Gain) loss on divestiture of Advanced Materials business	-1.7	111.6	0
Adjustment to contingent consideration	0	-13	0
Other non-cash items	9	5.5	0.1
Changes in operating assets and liabilities, excluding the effect of business acquisitions:
Accounts receivable	11.5	-22.3	39.4
Inventories (includes $18.4 million of step-up amortization in 2012)	3.8	25	75.7
Accounts payable	-15.5	12.5	-43
Refundable, prepaid and accrued income taxes	1.8	-21.1	41.2
Other, net	-11	-26.6	2.4
Net cash provided by operating activities	85.4	62.9	209.5
Investing activities
Expenditures for property, plant and equipment	-34.5	-53.1	-67.6
Cash (paid) for acquisitions or received from purchase adjustments	-24.6	0	6
Other, net	1	-5	5.1
Net cash provided by (used for) investing activities	-58.1	333.9	-56.5
Financing activities
Dividends paid	-9.3	0	0
Payments on long-term debt	0	-466.5	-213.5
Proceeds from revolving line of credit	14.5	0	0
Payments on revolving line of credit	-2	0	0
Payments related to VAC purchase price payable	-16.2	-23	0
Debt issuance costs	-0.1	-2.3	0
Payment related to surrendered shares	-0.7	-0.6	-0.3
Share repurchases	-35.2	-14.1	0
Proceeds from exercise of stock options	0.5	2.8	0
Net cash used for financing activities	-48.5	-503.7	-213.8
Effect of exchange rate changes on cash	-4.7	0.6	1.4
Cash and cash equivalents
Decrease from continuing operations	-25.9	-106.3	-59.4
Discontinued operations — net cash provided by (used) for operating activities	-0.8	-0.5	-1
Discontinued operations — net cash used for investing activities	0	-2.4	-4.1
Balance at the beginning of the year	118.4	227.6	292.1
Balance at the end of the year	91.7	118.4	227.6
Advanced Materials [Member]
Investing activities
Proceeds from divestiture of businesses	0	328.7	0
UPC Business [Member]
Investing activities
Proceeds from divestiture of businesses	$0	$63.30	$0

Statements_of_Consolidated_Cas1

Statements of Consolidated Cash Flows (Parenthetical) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2012
Payments of Dividends	$0
VAC [Member]
Amount of Inventory Step-Up Amortization	$18.40

Statements_of_Consolidated_Tot

Statements of Consolidated Total Stockholders' Equity (USD $)	Total	Share Based Compensation Expense Employees [Member]	Director [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]	Capital in Excess of Par Value [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
In Millions, except Share data in Thousands, unless otherwise specified								Share Based Compensation Expense Employees [Member]	Director [Member]
Beginning balance at Dec. 31, 2011				$44.50		$0.30	$625.50			$709.90	($7.40)	($93.40)
Beginning balance, shares at Dec. 31, 2011						31,865
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares repurchased						-9
Shares issued under share-based compensation plans						50
Shares issued (rounds to less than $0.1)						0
Shares issued under share-based compensation plans							0
Share-based compensation expense		-5.2	-0.5					5	0.5
Loss attributable to OM Group, Inc. common stockholders	-38.7									-38.7
Common stock cash dividends										0
Reacquired shares											-0.3
Foreign currency translation	20.7											20.7
Reclassification of hedging into earnings, net of tax												-1.9
Unrealized (loss) gain on cash flow hedges, net of tax	5.9											5.9
Pension and post-retirement obligation, net of tax	-19.3											-19.3
Loss attributable to the noncontrolling interest	7.1			-7.1
Sale of noncontrolling interest				0
Ending balance at Dec. 31, 2012	1,244.30			37.4	1,206.90	0.3	631.1			671.2	-7.7	-88
Ending balance, shares at Dec. 31, 2012						31,906
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares repurchased						-609
Shares issued under share-based compensation plans						182
Shares issued (rounds to less than $0.1)						0
Shares issued under share-based compensation plans							2.8
Share-based compensation expense		-5.7	-0.5					5.4	0.5
Loss attributable to OM Group, Inc. common stockholders	-84									-84
Common stock cash dividends										0
Reacquired shares											-14.6
Foreign currency translation	25											25
Reclassification of hedging into earnings, net of tax												0.2
Unrealized (loss) gain on cash flow hedges, net of tax	-0.3											-0.3
Pension and post-retirement obligation, net of tax	17.9											17.9
Loss attributable to the noncontrolling interest	1.8			0
Sale of noncontrolling interest				-37.4
Ending balance at Dec. 31, 2013	1,159.80			0	1,159.80	0.3	639.8			587.2	-22.3	-45.2
Ending balance, shares at Dec. 31, 2013						31,479
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares repurchased						-1,310
Shares issued under share-based compensation plans						103
Shares issued (rounds to less than $0.1)						0
Shares issued under share-based compensation plans							0.5
Share-based compensation expense		-7.1	-0.5					6.5	0.5
Loss attributable to OM Group, Inc. common stockholders	-172.6									-172.6
Common stock cash dividends										-9.3
Reacquired shares											-35.9
Foreign currency translation	-81.7											-81.7
Reclassification of hedging into earnings, net of tax												0.2
Unrealized (loss) gain on cash flow hedges, net of tax	0											0
Pension and post-retirement obligation, net of tax	-31.1											-31.1
Loss attributable to the noncontrolling interest	0			0
Sale of noncontrolling interest				0
Ending balance at Dec. 31, 2014	$836.90			$0	$836.90	$0.30	$647.30			$405.30	($58.20)	($157.80)
Ending balance, shares at Dec. 31, 2014						30,272

Significant_Accounting_Policie

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies
	Principles of Consolidation — OM Group, Inc. (the “Company”, “we”, “our”, “us”) is a technology-driven industrial company serving attractive global markets, including automotive systems, electronic devices, aerospace and defense, industrial and medical. We use innovative technologies to address customers' complex applications and demanding requirements. Our strategy is to grow organically through product and application innovation and new market and customer development, to grow strategically through complementary acquisitions to build-out our growth platforms, and to maximize total stockholder returns through a combination of business growth, financial discipline, optimal deployment of capital and continued operational excellence. Our objective is to deliver sustainable, profitable growth and create long-term stockholder value. The consolidated financial statements include the accounts of OM Group and its consolidated subsidiaries. We were formed in 1991 as a Delaware Corporation. Intercompany accounts and transactions have been eliminated in consolidation.
	Certain financial data may have been rounded. As a result of such rounding, the totals of data presented in this document may vary slightly from the actual arithmetical totals of such data.
	On November 24, 2014, we completed the acquisition of Ener-Tek International, Inc., which operates under the brand name Yardney Technical Products ("Yardney"), and now operates as a part of our Battery Technologies business. Based in East Greenwich, Rhode Island, Yardney is a designer, developer and manufacturer of high-performance lithium-ion and silver-zinc cells and batteries for niche applications in the defense and aerospace markets. We funded the $24.6 million acquisition price through existing cash balances.
	On May 31, 2013, we completed the sale of our Ultra Pure Chemicals business. The results of our Ultra Pure Chemicals business are reported as discontinued operations in the accompanying unaudited condensed consolidated financial statements and Notes to Consolidated Financial Statements for all periods presented. See note 5 - Acquisitions and Divestitures.
	On March 29, 2013, we completed the divestiture of our cobalt-based business. The transaction comprised the sale of the downstream portion of the business, (including its cobalt refinery assets in Kokkola, Finland) and the transfer of our 55% equity interests in the DRC-based joint venture known as GTL to the joint venture partners, subject to a security interest in our favor with respect to the joint venture's performance related to certain supply agreements. Until March 29, 2013, we consolidated the GTL joint venture because we had a controlling interest. Non-controlling interest was recorded for the remaining 45% interest. See note 5 - Acquisitions and Divestitures.
	The financial position, results of operations and cash flows of acquisitions are included in the Consolidated Financial Statements from the dates of acquisition.
	Unless otherwise indicated, all disclosures and amounts in the Notes to Consolidated Financial Statements relate to the Company's continuing operations.
	Use of Estimates - The preparation of financial statements, in conformity with US generally accepted accounting policies ("US GAAP"), requires management to make estimates and assumptions in certain circumstances that affect the amounts reported in the accompanying consolidated financial statements and notes. Actual results could differ from these estimates.
	Cash Equivalents - All highly-liquid investments, with a maturity of three months or less when purchased, are considered to be cash equivalents.
	Allowance for Doubtful Accounts - We have recorded an allowance for doubtful accounts to record accounts receivable at their estimated net realizable value. The allowance is based upon an analysis of historical bad debts, a review of the aging of accounts receivable and the current creditworthiness of customers. Accounts are written off against the allowance when it becomes probable that collections will not occur. Trade credit is generally extended on a short-term basis and accounts receivable generally do not bear interest.
	Inventories - Magnetic Technologies' inventories are valued using the average cost method. Cost of sales under the average cost method represents the weighted average cost of the items sold. We believe the average cost method provides for a better matching of inventory costs with related sales based on Magnetic Technologies' manufacturing process. Our remaining inventory is valued using First in, First out (FIFO). Inventory costs include raw materials, labor and manufacturing overhead. Inventory accounted for under the percentage-of-completion method is included in work-in-process inventory and represents accumulated contract costs less the portion of such costs allocated to delivered units. The costs attributed to units delivered are based on the estimated average cost of all units expected to be produced on a contract-by-contract basis.
	Changes in the price of rare earth and other materials can have a significant impact on inventory valuation. We evaluate the need for a lower of cost or market (“LCM”) adjustment to inventories based on the selling prices of our finished products generally at the end of the period. To the extent raw material prices increase subsequent to the balance sheet date, we consider these price movements in our LCM evaluation. Declines in the selling prices of our finished goods, which can result from decreases in the market price of raw materials or other factors, can result in our inventory carrying value being written down to a lower market value.
	Property, Plant and Equipment - Property, plant and equipment is recorded at historical cost less accumulated depreciation. Depreciation of plant and equipment, including assets recorded under capital leases, is provided by the straight-line method over the useful lives of 5 to 25 years for land improvements, 5 to 40 years for buildings and improvements, 5 to 15 years for machinery and equipment (with the majority in the range of 5 to 10 years), 5 to 10 years for furniture and fixtures and 3 to 5 years for vehicles and computers and related equipment. Leasehold improvements are depreciated over the shorter of the estimated useful life or the term of the lease.
	Long-lived Assets other than Goodwill - Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate the carrying amount may not be recoverable. Events or circumstances that would result in an impairment review primarily include operating losses, a significant change in the use of an asset, or the planned disposal or sale of the asset. The asset would be considered impaired when the future net undiscounted cash flows generated by the asset are less than its carrying value. An impairment loss would be recognized based on the amount by which the carrying value of the asset exceeds its estimated fair value.
	Goodwill and Intangible Assets - We evaluate the carrying value of goodwill and indefinite-lived intangible assets for impairment annually as of October 1 and between annual evaluations if changes in circumstances or the occurrence of certain events indicate potential impairment. If the carrying value of goodwill or an indefinite-lived intangible asset exceeds its fair value, an impairment loss is recognized.
	Intangible assets consist of (i) definite-lived assets subject to amortization and (ii) indefinite-lived intangible assets not subject to amortization. Definite-lived intangible assets consist principally of customer relationships, developed technology, know-how, capitalized software and license agreements and are being amortized using the straight-line or other appropriate method, if applicable. Indefinite-lived intangible assets consist of tradenames.
	Retained Liabilities of Businesses Sold - Retained liabilities of businesses sold include obligations related to our former Precious Metals Group (“PMG”), which was sold in 2003. Under terms of the sale agreement, we will reimburse the buyer of this business for certain items that become due and payable by the buyer subsequent to the sale date. Such items are principally comprised of taxes payable related to periods during which we owned PMG. The liability was $11.3 million and $12.3 million as of December 31, 2014 and 2013, respectively. Corresponding receivables related to the indemnification of the liabilities of $8.2 million and $9.1 million at December 31, 2014 and 2013, respectively, were recorded in Other non-current assets.
	Revenue Recognition — Except for revenue recognized under the percentage of completion method of accounting in Battery Technologies (see discussion below), we recognize revenue when persuasive evidence of an arrangement exists, unaffiliated customers take title and assume risk of loss, the sales price is fixed or determinable and collection of the related receivable is reasonably assured. Revenue recognition generally occurs upon shipment of product or usage of inventory consigned to customers. All amounts in a sales transaction billed to a customer related to shipping and handling are reported as sales.
	The Battery Technologies segment uses the percentage of completion method to recognize most of its revenue. Most defense contracts use the units-of-delivery method while most space contracts use the cost-to-cost method as the basis to measure progress toward completing a contract. Under the units-of-delivery method, revenues are recognized based on the contract price of units delivered. Under the cost-to-cost method, revenue is recognized based on the ratio of cost incurred compared to management's estimate of total costs expected to be incurred under the contract. The percentage of completion method requires substantial judgment on the part of management due to the duration of the contracts as well as the technical nature of the products involved. Contract revenues and cost estimates are reviewed at least quarterly and adjustments are reflected in the accounting period such amounts are determined. Billings in excess of amounts earned are deferred. Anticipated losses on contracts are recorded in full in the period in which the loss becomes evident.
	Cost of Goods Sold — Cost of goods sold is comprised of raw material costs, direct production, maintenance and utility costs, depreciation, other overhead costs and shipping and handling costs.
	Research and Development — Research and development costs are charged to expense when incurred, are included in selling, general and administrative expenses and amounted to $26.0 million, $26.3 million and $32.2 million in 2014, 2013 and 2012, respectively. These amounts do not include development and application engineering costs incurred in conjunction with fulfilling customer orders and executing projects.
	Accounting for Operating Leases — Lease expense is recorded on a straight-line basis. The noncancellable lease term used to calculate the amount of the straight-line expense is generally determined to be the initial lease term, including any optional renewal terms that are reasonably assured. Certain leases include escalating rent provisions and lease incentives which are recognized as lease expense on a straight-line basis over the lease term. Lease payments that depend on an existing index or rate are included in our minimum lease payments that are recognized as lease expense on a straight-line basis over the minimum lease term.
	Income Taxes — Deferred income taxes are provided to recognize the effect of temporary differences between financial and tax reporting. Deferred income taxes are not provided for undistributed earnings of foreign consolidated subsidiaries, to the extent such earnings are determined to be reinvested for an indefinite period of time.
	Foreign Currency Translation — The functional currency for most of our operating subsidiaries outside of the United States is the applicable local currency. For those operations, assets and liabilities are translated into U.S. dollars at period-ending exchange rates and revenues and expenses are translated into U.S. dollars using average exchange rates. The resulting translation adjustments are recorded as a component of Accumulated other comprehensive income (loss) in stockholders’ equity. Accordingly, foreign currency exchange gains and losses related to assets, liabilities and transactions denominated in other currencies (principally the Euro) are included in the Statements of Consolidated Operations.
	Derivative Instruments — We enter into derivative instruments and hedging activities to manage, where possible and economically efficient, commodity price risk, foreign currency exchange rate risk and interest rate risk related to borrowings. It is our policy to execute such instruments with creditworthy banks and not enter into derivative instruments for speculative purposes. All derivatives are reflected at their fair value and recorded in other current assets and other current liabilities as of December 31, 2013. There were no outstanding derivatives as of December 31, 2014. The accounting for the fair value of a derivative depends upon whether it has been designated as a hedge and on the type of hedging relationship. To qualify for designation in a hedging relationship, specific criteria must be met and appropriate documentation prepared. Changes in the fair values of derivatives not designated in a hedging relationship are recognized in earnings.
	From time to time we employ derivative instruments in connection with purchases and sales of inventory in order to establish a fixed margin and mitigate the risk of price volatility. Some customers request fixed pricing and we may use a derivative to mitigate price risk. While this hedging may limit our ability to participate in gains from favorable commodity price fluctuations, it eliminates the risk of loss from adverse commodity price fluctuations.
	Periodically, we enter into certain derivative instruments designated as cash flow hedges. For these hedges, the effective portion of the gain or loss from the financial instrument is initially reported as a component of Accumulated other comprehensive income (loss) in stockholders’ equity and subsequently reclassified into earnings in the same line as the hedged item in the same period or periods during which the hedged item affects earnings.

Recently_Issued_Accounting_Gui

Recently Issued Accounting Guidance	12 Months Ended
	Dec. 31, 2014
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recently Issued Accounting Guidance	Recently Issued Accounting Guidance
	In May 2014, the FASB issued ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606)” (“ASU 2014-09”). The update amends the guidance for revenue recognition to replace numerous, industry-specific requirements and converges areas under this topic with those of the International Financial Reporting Standards. The amendments are effective for reporting periods beginning after December 15, 2016, and early adoption is prohibited. Entities can transition to the standard either retrospectively or as a cumulative-effect adjustment as of the date of adoption. We are currently assessing the impact the adoption of ASU 2014-09 may have on our results of operations or financial position.
	In July 2013, the FASB issued ASU 2013-11 Presentation of Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward exists. The update requires companies to offset a liability recorded for an unrecognized tax benefit against a related deferred tax asset of a net operating loss carryforward, a similar tax loss or a tax credit carryforward if such settlement is required or expected in the event the uncertain tax position is disallowed. The amendments are effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. We adopted this guidance as of March 31, 2014 and reclassified a portion of our uncertain tax position accrual to net against the related deferred tax assets. Such adoption did not have an effect on our results of operations or financial position.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2014
Inventory, Net [Abstract]
Inventories	Inventories
	Inventories consist of the following as of December 31,
		2014		2013
	Raw materials and supplies	$	73.6	$	83.3
	Work-in-process	118.1		122.2
	Finished goods	36.7		35.4
		$	228.4	$	240.9

Property_Plant_and_Equipment_n

Property, Plant and Equipment, net	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment, Net [Abstract]
Property, Plant and Equipment, net	Property, Plant and Equipment, net
	Property, plant and equipment, net consists of the following as of December 31,
		2014			2013
	Land and improvements	$	37.6		$	39.6
	Buildings and improvements	138			145.8
	Machinery and equipment	346.4			350.4
	Furniture and fixtures	8.2			7.6
	Property, plant and equipment, at cost	530.2			543.4
	Less accumulated depreciation	(221.9		)	(197.8		)
		$	308.3		$	345.6
	Total depreciation expense on property, plant and equipment was $42.5 million in 2014, $47.7 million in 2013 and $58.7 million in 2012.

Acquisitions_and_Divestitures

Acquisitions and Divestitures	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
Acquisitions and Divestitures	Acquisitions and Divestitures
	(a) Acquisitions
	Yardney
	On November 24, 2014. we completed the acquisition of Ener-Tek International, Inc., which operates under the brand name Yardney Technical Products ("Yardney"). Based in East Greenwich, Rhode Island, Yardney is a designer, developer and manufacturer of high-performance lithium-ion and silver-zinc cells and batteries for niche applications in the defense and aerospace markets. We funded the $24.6 million acquisition price through existing cash balances. The balance sheet as the acquisition date is based on preliminary estimated purchase accounting. The purchase price was allocated to $10.1 million of net assets, including $5.5 million of identifiable intangibles. The remaining $14.5 million was recorded as goodwill, which is not expected to be deductible for tax purposes.
	VAC
	Our Magnetic Technologies segment consists of VAC Holding GmbH ("VAC"), which we acquired in 2011. The total purchase price of $812.2 million included cash consideration of $686.2 million, withheld consideration of $86.3 million, and the issuance of Company shares valued at $39.7 million. The withheld consideration relates to potential indemnification claims made by OM Group and accepted by the seller, if any, within two years of the closing date of the acquisition with certain exceptions related to tax matters. In August 2013 we remitted a payment of $23.0 million to the seller of VAC. In December 2014, we remitted a payment of $16.2 million to the seller of VAC and charged certain tax assessments related to pre-acquisition tax years of $1.6 million against the outstanding withholding liability.
	We now expect matters relating to the withheld consideration to be resolved in 2015. Due to the length of time over which these payments are being made, these payments are classified as financing activities within the Statement of Consolidated Cash Flows. The 2013 payment was previously classified in investing activities, and we have now correctly classified this payment in financing activities.
	We are engaged in arbitration with the seller regarding the remainder of the withheld consideration which covers unresolved claims.
	(b) Divestitures
	Advanced Materials
	On March 29, 2013, we completed the divestiture of our cobalt-based business. The transaction comprised the sale of the downstream portion of the business (including our cobalt refinery assets in Kokkola, Finland), and the transfer of equity interests in the DRC-based joint venture, known as GTL, to the joint venture partners, subject to a security interest in our favor with respect to the joint venture's performance related to certain supply arrangements.
	In connection with this transaction we received cash proceeds of $328.7 million. At closing, net proceeds of $302.1 million were received, and we received additional proceeds of $26.6 million as an adjustment to the purchase price based on a post-closing analysis of the closing balance sheet in July 2013. Including the adjustment to the purchase price, a loss of $111.6 million was recorded on the divestiture in 2013, which included a $10.3 million write-off of deferred financing fees related to the required debt pre-payment, a reserve for a note receivable from joint venture partner of $16.0 million and transaction expenses of $9.0 million.
	The sale agreement for the downstream portion of the business also provides for potential future additional cash consideration of up to $110.0 million based on the business achieving certain revenue targets over a period of three years. Using our projected trends of cobalt prices and volumes, it is not probable that the business will meet the revenue targets, and no value was assigned to the potential future cash consideration while calculating the loss on the divestiture or at December 31, 2013 and 2014.
	Following the sale, to assist in the transition of the downstream business, we entered into two agreements with the buyer pursuant to which: (1) We act as intermediary in a supply agreement between GTL and the buyer, in back-to-back arrangements for a period of at least two years. We met the cobalt feed supply target under that agreement in October 2014 and the supply agreement will terminate in March 2015. (2) We also served as the U.S. distributor for refined cobalt products in primarily back-to-back arrangements until December 31, 2013.
	Ultra Pure Chemicals
	On May 31, 2013, we completed the sale of our Ultra Pure Chemicals (UPC) business. In connection with this transaction we received cash proceeds of $63.3 million, which included an estimated $3.0 million for excess working capital. A loss of $9.8 million, net of tax, was recorded on the divestiture, which included a gain of $1.5 million on the sale of net assets offset by the realization of a loss in accumulated other comprehensive income of $8.8 million, a $1.5 million write-off of deferred financing fees related to the required debt pre-payment and transaction expenses of $1.0 million. In the second quarter 2014, we settled the outstanding working capital items and recorded an additional loss of $0.2 million.
	The results of our UPC business are reported in discontinued operations in the accompanying consolidated financial statements and notes to the consolidated financial statements for all periods prior to the UPC sale.  As required, annual interest expense of $1.0 million and $2.5 million for the periods ending December 31, 2013 and 2012, respectively, related to the debt repaid with the proceeds from the sale of the business was allocated to discontinued operations for all periods prior to the UPC sale. A summary of our discontinued operations activity is as follows:
		Twelve Months Ended December 31
	(In millions except per share data)		2014			2013			2012
	Net Sales		$	—		$	38.3		$	93.4
	Loss from operations of divested business (net of tax)		$	(0.1	)	$	(2.5	)	$	(0.4	)
	Loss on disposal of business (net of tax)		(0.2		)	(9.8		)	—
	Loss from discontinued operations (net of tax)		$	(0.3	)	$	(12.3	)	$	(0.4	)
	Loss per share from discontinued operations (net of tax)
	Basic and diluted		$	(0.01	)	$	(0.39	)	$	(0.01	)

Goodwill_and_Other_Intangible_

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets
	Goodwill is tested for our reporting units on an annual basis, or more frequently as impairment indicators arise. We have the option to perform a qualitative evaluation about the likelihood of goodwill and indefinite lived intangible impairment to determine whether we should quantitatively calculate the fair value of each of our reporting units. If, after considering all events and circumstances that support a qualitative evaluation, we determine that it is not more-likely-than-not that the fair value of our reporting units is less than the respective carrying value, then performing the two-step quantitative approach would be considered unnecessary. Conversely, if applying the qualitative evaluation indicates that it is more-likely-than-not that the fair value is less than the carrying value, then we would proceed with the first step of the two-step quantitative approach and continue with the quantitative analysis to determine if in fact the reporting unit or units' carrying value exceeds its fair value.
	We estimate the fair value of a reporting unit (including goodwill) and compare that amount to the carrying value of that reporting unit. If the estimated fair value of the reporting unit is less than its carrying value, a second step would be undertaken to determine the implied fair value of goodwill of the reporting unit, which is then compared with the carrying value of the goodwill of the reporting unit. This second step would include valuing all of the tangible and intangible assets and liabilities of the reporting unit as if they had been acquired in a business combination on the testing date. We have developed a model to estimate the fair value of the reporting units utilizing a discounted cash flow valuation technique (“DCF model”). We selected the DCF model as we believe it is comparable to what would be used by market participants to estimate fair value of our reporting units. The DCF model incorporates our estimates of future cash flows; future growth rates; terminal value amounts; allocations of certain assets, liabilities and cash flows among reporting units; and the applicable weighted-average cost of capital (the “WACC”) used to discount those estimated cash flows. These estimates require significant judgment and are consistent with our forecast and long-range plans and are considered level 3 inputs under the fair value hierarchy.
	We conduct our annual goodwill impairment test as of October 1. The results of testing as of October 1, 2014 for all reporting units except Magnetic Technologies confirmed that the estimated fair value of each of the reporting units substantially exceeded its carrying value and no impairment loss was required to be recognized. During a strategic evaluation by the management team, led by the new business leader, of the business and of various opportunities to optimize performance, we noted indicators of potential impairment in the Magnetic Technologies business, including deteriorating European macroeconomic conditions and increasing competition. The resulting test confirmed that the carrying value of the Magnetic Technologies business exceeded its fair value for goodwill. In the fourth quarter of 2014, we performed the second step as discussed above and a non-cash goodwill impairment charge of $168.7 million was recognized.
	The results of testing as of October 1, 2013 and 2012 for all reporting units except Magnetic Technologies in 2012 confirmed that the estimated fair value of each of the reporting units substantially exceeded its carrying value and no impairment loss was required to be recognized. The October 1, 2012 estimated fair value of the Magnetic Technologies reporting unit exceeded its carrying value by 4%.
	We believe the assumptions used in our impairment testing were consistent with the risk inherent in the business models of the reporting unit at the time the impairment test was performed. Although we believe the forecasts, assumptions, judgments and estimates used are reasonable and appropriate, different forecasts, assumptions, judgments and estimates could materially affect the goodwill test and, potentially, our results of operations and financial position. The change in the carrying amount of goodwill is as follows:
		Magnetic Technologies			Advanced			Specialty			Battery			Continuing Operations			Discontinued Operations			Consolidated
					Materials			Chemicals			Technologies
	Balance at January 1, 2013	$	205.2		$	103.3		$	154.4		$	65.4		$	528.4		$	15		$	543.4
	Divestitures and adjustments	—			(103.3		)	—			—			(103.3		)	(15.0		)	(118.3		)
	Foreign currency translation adjustments	9.3			—			(1.3		)	(0.3		)	7.7			—			7.7
	Balance at December 31, 2013	214.5			—			153.1			65.1			432.7			—			432.7
	Impairment	(168.7		)	—			—			—			(168.7		)	—			(168.7		)
	Acquisition	—			—			—			14.5			14.5			—			14.5
	Foreign currency translation adjustments	(19.3		)	—			(6.3		)	(0.3		)	(25.9		)	—			(25.9		)
	Balance at December 31, 2014	$	26.5		$	—		$	146.8		$	79.3		$	252.6		$	—		$	252.6
	Intangible assets consist of (i) definite-lived assets subject to amortization and (ii) indefinite-lived intangible assets not subject to amortization. All intangible assets subject to amortization are amortized on a straight-line basis over the estimated useful lives or other appropriate methods if applicable. During a strategic evaluation by the management team we noted indicators of potential impairment at the Magnetic Technologies business as discussed above. In the fourth quarter of 2014, we performed the DCF calculation based on relief of royalty method and determined that the fair value for the Magnetic Technologies tradename was less than the carrying value and a non-cash impairment charge of $26.7 million was recognized.
	A summary of intangible assets follows:
		2014												2013
		Carrying Value			Accumulated			Impairment			Net			Carrying Value			Accumulated			Net
					Amortization (a)												Amortization (a)
	Tradenames	$	114.1		$	(9.6	)	$	(26.7	)	$	77.8		$	117		$	(2.9	)	$	114.1
	Customer relationships	218.2			(90.1		)	—			128.1			234.5			(82.4		)	152.1
	Developed technology	135.5			(36.1		)	—			99.4			136.5			(19.9		)	116.6
	Know-how	20.1			(4.6		)	—			15.5			18.6			(3.6		)	15
	Capitalized software	22.3			(18.6		)	—			3.7			22			(17.4		)	4.6
	Other intangibles	2.9			(2.6		)	—			0.3			4.2			(3.6		)	0.6
	Total	$	513.1		$	(161.6	)	$	(26.7	)	$	324.8		$	532.8		$	(129.8	)	$	403
	(a) - Actual amounts of amortization expense may differ from the estimated amounts due to changes in foreign currency exchange rates, impairment of intangible assets, intangible assets additions, accelerated amortization of intangible assets, acquisitions and divestitures and other factors.
	The weighted average amortization period is 10 years for customer relationships, 12 years for developed technology, 16 years for know-how and 3 year for capitalized software. Indefinite-lived intangible assets are tested for impairment annually and between annual evaluations if changes in circumstances or the occurrence of certain events indicate potential impairment.
	Amortization expense related to intangible assets for the years ended December 31, 2014, 2013 and 2012 was $25.0 million, $26.1 million and $25.5 million, respectively. In 2013 we divested the UPC business which had intangible assets with a carrying value of $17.2 million.
	We estimate that the annual pre-tax amortization expense will be approximately $25.2 million for 2015, $24.9 million for 2016, $24.8 million for 2017, $20.7 million for 2018 and $21.1 million for 2019.
	The goodwill and intangible asset impairment led to an impairment review of the Magnetic Technologies long-lived assets other than goodwill and indefinite lived intangibles. The future net undiscounted cash flows generated by the assets were greater than the carrying value, indicating no impairment of long-lived assets.

Debt

Debt	12 Months Ended
	Dec. 31, 2014
Debt Instruments [Abstract]
Debt	Debt
	On September 4, 2013 we entered into a new five-year Senior Secured Revolving Credit Facility (“the Facility”), and terminated our previous credit facility dated August 2, 2011 that was scheduled to expire in August 2016. The Facility provides for $350 million of revolving borrowing capacity and includes an expansion option of up to an additional $150 million, subject to certain conditions. The borrowers under the agreement are the Company, Harko C.V. (“Harko”), a limited partnership organized under the laws of the Netherlands, and VAC Germany GmbH (“VAC”), a limited liability company under the laws of Germany. Harko and VAC are wholly-owned subsidiaries of the Company. The Facility matures on September 4, 2018.
	In the first six months of 2013 we repaid the Term A and Term B loans under the previous credit facility with the proceeds from the divestitures of the Advanced Materials and UPC businesses, as required, and cash on hand. Related to these required pre-payments, we included the write-off of $10.3 million and $1.5 million of deferred financing fees in the losses on divestitures of the Advanced Materials and UPC businesses, respectively.
	The obligations of the Company under the Facility are guaranteed by certain of the Company’s material U.S. subsidiaries. The obligations of Harko and VAC under the Facility are guaranteed by the Company and certain of the Company’s material subsidiaries, subject to certain exceptions including financial assistance limitations in certain foreign jurisdictions. In addition, the obligations of the Company under the Facility are secured by a first priority security interest in substantially all of the existing and future personal property of the Company and certain of the Company’s material U.S. subsidiaries, including 65% of the voting capital stock of certain of the Company’s direct foreign subsidiaries. The obligations of Harko and VAC under the Facility are secured by a first priority security interest in certain of the existing and future personal property of Harko, VAC and certain of the Company’s subsidiaries and a 100% pledge of the voting capital stock of certain of the Company’s subsidiaries, subject to certain exceptions, including financial assistance limitations in certain foreign jurisdictions.
	The interest rates applicable to loans under the Facility will be at our option and equal to either a base rate or a LIBOR rate, in each case plus an applicable margin percentage. The base rate will be the highest of (i) the federal funds rate plus 0.50%, (ii) the prime rate or (iii) the LIBOR rate with a maturity of one month plus 1.00%. The applicable margin percentage is based on the leverage ratio of the Company. The range of the applicable margin percentage is 1.125% to 2.000% in the case of LIBOR advances and 0.125% to 1.000% in the case of base rate advances.
	The Facility contains customary representations and warranties and certain covenants that limit the ability of the Company and its restricted subsidiaries to, among other things: (i) incur or guarantee additional indebtedness; (ii) redeem, repurchase or pay distributions on capital stock or redeem or repurchase subordinated debt; (iii) make investments; (iv) sell assets; (v) enter into agreements that restrict distributions or other payments from restricted subsidiaries to the Company; (vi) incur or suffer to exist liens securing indebtedness; (vii) consolidate, merge or transfer all or substantially all of their assets; and (viii) engage in transactions with affiliates. In addition, the Facility contains financial covenants that limit capital expenditures in any fiscal year and that measure (i) the ratio of the Company’s total funded indebtedness net of certain cash to the amount of the Company’s consolidated EBITDA and (ii) the ratio of the amount of the Company’s consolidated EBITDA to the Company’s cash interest expense, as defined in the agreement.
	As of December 31, 2014, we had $12.5 million outstanding under the Facility which was repaid with available cash in January 2015. We are in compliance with all Facility covenants.
	Interest paid on long-term debt was $0.0 million, $6.9 million and $38.4 million in 2014, 2013 and 2012, respectively. As required, interest expense of $1.0 million and $2.5 million has been allocated to discontinued operations for 2013 and 2012, respectively. No interest was capitalized in 2014, 2013 or 2012.

Derivative_Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 2014
Derivative Instruments and Hedges, Assets [Abstract]
Derivative Instruments	Derivative Instruments
	All derivatives are reflected on the balance sheet at fair value and recorded in other current assets and other current liabilities in the Consolidated Balance Sheets. The accounting for the fair value of a derivative depends upon whether it has been designated as a hedge and on the type of hedging relationship. Changes in the fair value of derivative instruments are recognized immediately in earnings, unless the derivative is designated as a hedge and qualifies for hedge accounting. Under hedge accounting, recognition of derivative gains and losses can be matched in the same period with that of the hedged exposure and thereby minimize earnings volatility.
	For a fair value hedge, the change in fair value of the hedging instrument and the change in fair value of the hedged item attributable to the risk being hedged are both recognized currently in earnings. For a cash flow hedge, the effective portion of the change in fair value of a hedging instrument is initially recognized in Accumulated other comprehensive income (loss) (“AOCI(L)”) in stockholders’ equity and subsequently reclassified to earnings when the hedged item affects income. Any ineffective portion of the change in fair value of a cash flow hedge is recognized immediately in earnings.
	Commodity Price Risk
	From time to time we employ derivative instruments in connection with certain purchases of certain commodities in order to establish a fixed margin and mitigate the risk of price volatility. This hedging limits our ability to participate in gains from favorable commodity price fluctuations and it limits the risk of loss from adverse commodity price fluctuations.
	Derivative instruments employed to manage commodity price risk include some contracts designated as cash flow hedges as well as some other contracts that are not designated as hedges for accounting purposes.
	In May 2013, we entered into nickel forward derivative contracts to establish a fixed margin and mitigate the risk of price volatility related to certain sales expected in 2013 and 2014 of nickel-containing finished products that were priced on a formula that included a fixed nickel price component. These forward derivative contracts were designated
	as cash flow hedges for accounting purposes and were settled during the second quarter 2014. In October 2012, we entered into nickel forward derivative contracts to establish a fixed margin and mitigate the risk of price volatility related to certain sales expected in 2013 of nickel-containing finished products that were priced based on a formula that included a fixed nickel price component and were settled in 2013. These forward derivative contracts have been designated as cash flow hedges for accounting purposes.
	Foreign Currency Exchange Rate Risk
	Our primary Finnish operating subsidiary was included in the divestiture of our cobalt-based business on March 29, 2013. The functional currency for this subsidiary was the U.S. dollar since a majority of its purchases and sales were denominated in U.S. dollars. While a majority of the subsidiary’s raw material purchases were in U.S. dollars, it had some Euro-denominated operating expenses. From time to time, we entered into foreign currency forward contracts to mitigate a portion of the earnings volatility in those Euro-denominated cash flows due to changes in the Euro/U.S. dollar exchange rate. As of December 31, 2014, 2013, and 2012 we had no Euro forward contracts outstanding. In 2012 we reclassified the previous cumulative loss from the 2011 contracts into earnings. We designated these foreign currency derivatives as cash flow hedges of the subsidiary's forecasted Euro-denominated expenses.
	Interest Rate Risk
	From time to time we utilized interest rate swap agreements to partially reduce risks related to variable rate financing agreements that are subject to changes in the market rate of interest.
	We had interest rate swaps with notional values that totaled $114.5 million at December 31, 2012 and AOCI(L) included a cumulative loss of $0.1 million related to these contracts. Following the full repayment of the Term B facility at the end of March 2013, we elected in April 2013 to terminate all the remaining interest swaps contracts. The AOCI at the time of the termination represented an immaterial cumulative loss related to these contracts which was reclassified to earnings in the second quarter 2013.
	There was no hedge ineffectiveness in 2014, 2013 or 2012 for hedges.
	There were no outstanding hedge contracts in the Consolidated Balance Sheet as of December 31, 2014.
	The following table summarizes the effect of derivative instruments as recorded in the Statement of Consolidated Operations:
	Derivatives in Cash Flow Hedging Relationships
		Amount of Gain (Loss) on Derivative Recognized in AOCI(L) (Effective Portion) for the Year Ended December 31,
		2014				2013				2012
	Euro forward contracts	$	—			$	—			$	6
	Commodity contracts	—				(0.3		)		—
	Interest rate swap agreements	—				—				(0.1		)
	Total	$	—			$	(0.3	)		$	5.9
		Location of Gain (Loss) Reclassified		Amount of Gain (Loss) Reclassified from
		from AOCI(L) into Income		AOCI(L) into Income (Effective Portion)
				for the Year Ended December 31,
		(Effective Portion)		2014				2013				2012
	Euro forward contracts	Cost of goods sold		$	—			$	—			$	2.3
	Commodity contracts	Cost of goods sold		(0.2		)		(0.2		)		—
	Interest rate swap agreements	Interest expense		—				—				(0.4		)
	Total			$	(0.2	)		$	(0.2	)		$	1.9

Fair_Value_Disclosures

Fair Value Disclosures	12 Months Ended
	Dec. 31, 2014
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Fair Value Disclosures	Fair Value Disclosures
	The following table shows the Company’s assets and liabilities accounted for at fair value on a recurring basis:
					Fair Value Measurements at Reporting Date Using
					Quoted Prices in	Significant Other	Significant
					Active Markets for	Observable Inputs	Unobservable Inputs
					Identical Assets
	Description	December 31, 2014			(Level 1)	(Level 2)	(Level 3)
	Liabilities:
	Contingent consideration payable	$	1.4		—	—	1.4
	The fair value of the derivative instruments have been determined based on the market equivalents at the balance sheet date, taking into account current commodity forward rates, therefore, they are classified within Level 2 of the valuation hierarchy. Our valuation techniques and Level 3 inputs used to estimate the fair value of the contingent consideration payable in connection with our acquisition of Rahu Catalytics Limited ("Rahu") are described below. There were no transfers into or out of Levels 1, 2 or 3 in 2014 or 2013.
	The following table summarizes changes in Level 3 liabilities measure at fair value on a recurring basis:
		Contingent Consideration
	Fair Value at December 31, 2013	$	1.4
	Accretion expense	0.2
	Foreign exchange	(0.2		)
	Fair Value at December 31, 2014	$	1.4
	We acquired Rahu on December 22, 2011. The purchase price included contingent consideration of up to an additional €20.0 million ($24.3 million at December 31, 2014) based on achieving certain volume targets over a fifteen year period ending on December 31, 2026. We estimated the fair value of the contingent consideration liability using probability-weighted expected future cash flows and applied a discount rate that appropriately captured a market participant's view of the risk associated with the liability. The liability for contingent consideration is included in Other non-current liabilities in the Consolidated Balance Sheet. The valuation of contingent consideration is classified utilizing Level 3 inputs consistent with reasonably available assumptions which would be made by other market participants. There are many factors that could impact the likelihood that we will pay the contingent consideration, and therefore, affect its value. Such factors include the overall economic conditions and our ability to drive sales volumes as planned. Subsequent to the date of acquisition the estimated fair value of the contingent consideration was reduced to €1.0 million ($1.4 million)after an evaluation of new information available in the fourth quarter of 2013. The change was reflected within Other income in the 2013 Consolidated Statement of Operations. A change in a market participant view of risks could also impact the value of the contingent consideration.
	We also hold financial instruments consisting of cash, accounts receivable, and accounts payable. The carrying amounts of cash, accounts receivable and accounts payable approximate fair value due to the short-term maturities of these instruments. Revolver debt had a carrying value of $12.5 million at December 31, 2014 and is the approximate fair value due to the the short-term nature of the instrument. There was no long-term debt outstanding as of December 31, 2014 or 2013. Derivative instruments are recorded at fair value as indicated above.
	We utilize a “relief from royalty” methodology in estimating fair values for indefinite-lived tradenames. The methodology estimates the fair value of each trade name by determining the present value of the royalty payments that are avoided as a result of owning the tradename and includes judgmental assumptions about sales growth that are consistent with the assumptions used to determine the fair value of reporting units in our goodwill testing. The fair value measurements were calculated using unobservable inputs, classified as Level 3, requiring significant management judgment due to the absence of quoted market prices or observable inputs for assets of a similar nature.
	Accounts receivable potentially subjects us to a concentration of credit risk. We maintain significant accounts receivable balances with several large customers. At December 31, 2014 and 2013 the accounts receivable balance from our largest customer represented 2% of the Company’s net accounts receivable, respectively. Generally, we do not obtain security from our customers in support of accounts receivable.
	Sales to the top three customers in the Battery Technologies segment represented approximately 49%, 48% and 52% of Battery Technologies’ net sales in 2014, 2013 and 2012, respectively. The loss of one or more of these customers could have a material adverse effect on Battery Technologies’ business, results of operations or financial position.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes
	Loss from continuing operations before income tax expense consists of the following:
			Year Ended December 31
			2014			2013			2012
	United States		$	(9.0	)	$	(13.6	)	$	(12.3	)
	Outside the United States		(163.8		)	(49.2		)	(36.3		)
			$	(172.8	)	$	(62.8	)	$	(48.6	)
	Income tax (benefit) expense is summarized as follows:
			Year Ended December 31
			2014			2013			2012
	Current tax provision (benefit):
	United States:
	Federal		$	1.4		$	0.6		$	(3.1	)
	State and local		0.2			—			—
	Outside the United States		15.1			17.4			30.1
	Total current		16.7			18			27
	Deferred tax provision (benefit):
	United States		(1.4		)	0.6			2.4
	Outside the United States		(15.8		)	(7.9		)	(32.6		)
	Total deferred		(17.2		)	(7.3		)	(30.2		)
			$	(0.5	)	$	10.7		$	(3.2	)
	A reconciliation of income taxes computed using the United States statutory rate to income taxes computed using our effective income tax rate is as follows:
			Year Ended December 31
			2014			2013			2012
	Loss from continuing operations before income tax expense		$	(172.8	)	$	(62.8	)	$	(48.6	)
	Income taxes at the United States statutory rate (35)%		(60.5		)	(21.9		)	(17.1		)
	Increase (decrease) in taxes resulting from:
	Effective tax rate differential on income outside of the United States		—			19.3			(3.3		)
	Repatriation of foreign earnings		2.3			(1.7		)	7.4
	Goodwill impairment		52.1			—			—
	Valuation allowance		6.7			13.2			3.7
	Uncertain tax positions		(1.1		)	0.1			(1.9		)
	Allowance on GTL prepaid tax asset		—			0.4			5.6
	Other, net		—			1.3			2.4
	Income tax expense (benefit)		$	(0.5	)	$	10.7		$	(3.2	)
	Effective income tax rate		(a)			(a)			6.5		%
	(a)	not meaningful
	The effective income tax rate for the year ended December 31, 2014 is impacted by the VAC intangible asset impairment charges of $195.4 million and other cost reduction charges (see Note 6 for further discussion on the intangible asset impairment charges). There is no tax benefit for the $168.7 million goodwill portion of the impairment charges due to its permanent nature.
	Excluding the impact of the VAC goodwill and intangible asset impairment charges of $195.4 million and other business improvement and cost reduction charges of $10.0 million, the effective tax rate for the year ended December 31, 2014 would have been 27.4%. This rate is lower than the U.S. statutory tax rate primarily due to income earned in tax jurisdictions with lower statutory rates than the U.S., and our financing structure, partially offset by losses and carry-forwards in certain jurisdictions (including the U.S. and Germany) with no corresponding tax benefit.
	The effective income tax rate for the year ended December 31, 2013 is impacted by the loss of $111.6 million related to the divestiture of the Advanced Materials business. There was no tax benefit on the loss on divestiture of the Advanced Materials business due to our legal entity and tax structure.
	Excluding the impact of loss on sale of advanced materials business of $111.6 million, the effective tax rate for the year ended December 31, 2013 would have been 22.1%. This rate is lower than the U.S. statutory tax rate primarily due to income earned in tax jurisdictions with lower statutory rates than the U.S., and our financing structure, partially offset by losses and carry-forwards in certain jurisdictions (including the U.S. and Germany) with no corresponding tax benefit.
	The effective income tax rate for the year ended December 31, 2012 was impacted by VAC purchase accounting related inventory charges of $55.9 million and GTL. During 2012, we recorded a tax expense of $10.4 million related to GTL. This includes a $5.6 million tax expense related to GTL prepaid tax asset impairment and $6.6 million related to other GTL permanent differences, of which our share was 55%, or $6.7 million.
	Excluding the impact of VAC purchase accounting related inventory charges and GTL discrete and permanent items, the effective tax rate for the year ended December 31, 2012 would have been 31.8%. This rate is lower than the U.S. statutory tax rate primarily due to income earned in tax jurisdictions with lower statutory rates than the U.S., and our internal financing structure, partially offset by losses and carry-forwards in certain jurisdictions (including the U.S. and Germany) with no corresponding tax benefit.
	During fourth quarter of 2012, the Company received a $37.9 million income tax refund which was included in the Refundable, prepaid and accrued income taxes in the Statement of Consolidated Cash Flows for December 31, 2012.
	We intend to repatriate only future earnings and therefore have not provided additional United States income taxes on approximately $402 million of undistributed earnings of consolidated foreign subsidiaries. Such earnings could become taxable upon the sale or liquidation of these foreign subsidiaries or upon dividend repatriation. Our intent is for such earnings to be permanently reinvested by the foreign subsidiaries. It is not practicable to estimate the amount of unrecognized withholding taxes and tax liability on such earnings.
	We file income tax returns in the U.S. federal jurisdiction, and various state and foreign jurisdictions. Our major tax jurisdictions include the U.S. and Germany. With few exceptions, we are no longer subject to U.S. federal, state and local, or non-U.S. income tax examinations by tax authorities for years before 2006. The Internal Revenue Service completed the examination of our 2010 U.S. federal income tax return, and Finnish tax authorities completed the examination of our Finnish tax returns for the years 2007-2011.  VAC's German tax returns have been audited through 2005. We are indemnified, subject to certain limitations, for any pre-acquisition income tax liabilities of VAC. German tax authorities are currently examining VAC's income tax returns for the years 2006-2011.
	Income tax payments were $18.8 million, $47.2 million and $33.9 million in 2014, 2013 and 2012, respectively.
	Significant components of our deferred income taxes are as follows:
			December 31
			2014			2013
	Employee benefit accruals		$	58.6		$	44.7
	Foreign operating loss carryforwards		6.5			8.3
	Foreign tax credit carryforwards		17.3			23.1
	State operating loss carryforwards		7.8			7.6
	Operating accruals		48.4			42.3
	Investment credit carryforwards		2.6			3.3
	Valuation allowance		(91.9		)	(83.6		)
	Deferred tax assets		49.3			45.7
	Depreciation		(31.2		)	(37.5		)
	Amortization		(88.5		)	(107.7		)
	Other		(0.2		)	(1.0		)
	Deferred tax liabilities		(119.9		)	(146.2		)
	Net deferred tax liabilities		$	(70.6	)	$	(100.5	)
	Deferred income taxes are recorded in the Consolidated Balance Sheets in the following accounts:
		December 31
		2014			2013
Other current assets		$	2.1		$	2.4
Other non-current assets		5.3			6.4
Other current liabilities		(3.2		)	(6.8		)
Deferred income taxes — non-current liabilities		(74.8		)	(102.5		)
		$	(70.6	)	$	(100.5	)
We have a U.S. net deferred tax asset of $1.4 million which is expected to be recovered based on temporary differences that will reverse in 2015-2016. At December 31, 2014 and 2013, we had U.S state net operating loss carryforwards representing a potential future tax benefit of $7.8 million and $7.7 million, respectively. These carryforwards expire at various dates from 2015 through 2034. We have recorded a full valuation allowance against the U.S state net operating loss carryforwards. We have foreign net operating loss carryforwards of $30.6 million, representing a potential future tax benefit of $6.5 million in various jurisdictions, some of which expire in 2018 through 2033, and some of which have no expiration. We have established a $1.8 million valuation allowance against the foreign net operating loss carryforwards as we believe that some of these assets will more likely than not be realized. We have foreign investment tax credit and allowance carryforwards of $2.6 million, of which $1.9 million expire in 2028, while the remaining $0.7 million have no expiration. We have recorded a $1.9 million valuation allowance against the foreign investment tax credit and allowance carryforwards as we believe that a portion of these assets will not be realized.
For the year ended December 31, 2014, our valuation allowance increased primarily due to the increase in foreign carryforwards.
A reconciliation of the beginning and ending amount of uncertain tax positions is as follows:
Balance at January 1, 2013		$	18
Additions for tax positions related to the current year		0.6
Reductions for tax positions of prior years		(3.4		)
Foreign currency translation		0.3
Balance at December 31, 2013		15.5
Additions for tax positions related to the current year		0.4
Addition of receivable for prior year tax position		(0.7		)
Reductions for tax positions of prior years		(0.6		)
Reductions for lapses of statute of limitations		(0.1		)
Foreign currency translation		(0.8		)
Balance at December 31, 2014		$	13.7
With the exception of those relating to the VAC acquisition, all uncertain tax positions would affect the effective tax rate if recognized. However, $6.1 million of the uncertain tax positions could be offset by tax credit carryforwards, which, if recognized, would be offset by an adjustment to the deferred tax assets. The decrease in uncertain tax positions in 2014 primarily results from effective settlements during 2014 in various tax jurisdictions. The decrease in uncertain tax positions in 2013 primarily results from the effective settlements during 2013 in various tax jurisdictions and the transfer of our equity interests in GTL as part of the divestiture of the Advanced Materials business. At December 31, 2014, the liability for uncertain tax positions includes $5.9 million for which it is reasonably possible that the uncertain tax position will decrease within the next twelve months. These uncertain tax positions primarily relate to acquired businesses and may decrease upon effective settlement.
We recognize interest accrued related to uncertain tax positions and penalties as a component of income tax expense. During 2014 and 2013 we recognized an immaterial benefit related to interest and penalties. At December 31, 2014 and 2013, we had $0.6 million and $0.8 million, respectively, accrued for interest and penalties.

Pension_and_Other_PostRetireme

Pension and Other Post-Retirement Benefit Plans	12 Months Ended
	Dec. 31, 2014
Pension and Other Postretirement Benefit Expense [Abstract]
Pension and Other Post-Retirement Benefit Plans	Pension and Other Post-Retirement Benefit Plans
	We have defined contribution plans covering substantially all eligible U.S. employees. Contributions are directed by the employee into various investment options. These defined contribution plans do not have any direct ownership of the Company’s common stock. Under these plans, we match participants’ contributions based on plan provisions. Certain plans provide for a discretionary Company contribution based on employee compensation. We maintain additional defined contribution plans in certain locations outside the United States. Aggregate defined contribution plan expenses were $3.3 million, $4.7 million and $4.9 million in 2014, 2013 and 2012, respectively.
	We have defined benefit pension obligations at VAC, substantially all of which are unfunded. VAC sponsors various defined benefits plans for its employees, including pension, early retirement benefits and anniversary benefits, mainly in Germany.
	The EaglePicher Technologies ("EPT") pension plans consist of four, non-contributory, defined benefit pension plans. The Technologies Salaried Plan is a defined benefit, cash balance plan that covers EaglePicher Technologies salaried employees hired prior to January 1, 2007. The Technologies Hourly Plan is a defined benefit plan that covers EaglePicher Technologies non-union hourly employees hired prior to January 1, 2007 and union hourly employees hired prior to May 3, 2008. We also hold the liabilities of two frozen defined benefit pension plans. Pension benefits are paid to plan participants directly from pension plan assets. In 2014 we offered lump-sum payments to terminated vested participants in the EPT pension plans. $29.6 million was paid out of plan assets to participants who elected the lump sum payment, and we recorded a $3.2 million pre-tax pension settlement expense.
	In addition to the pension liabilities for VAC and EPT, we have a non-contributory, defined benefit pension plan for certain retired employees in the United States related to a divested business. Pension benefits under this plan are paid to plan participants directly from pension plan assets.
	Certain other non-U.S. employees are covered under other defined benefit plans. These other non-U.S. plans are not material.
	We also have an obligation to our former chief executive officer in settlement of an unfunded supplemental executive retirement plan (“SERP”). Payments under the SERP are made directly from the Company.
	The following table sets forth the changes in the benefit obligation and the plan assets during the year and reconciles the funded status of the defined benefit plans with the amounts recognized in the Consolidated Balance Sheet at December 31:
		Pension Benefits
		U.S. Plans							Non-U.S. Plans
		2014				2013			2014			2013
	Change in benefit obligation
	Projected benefit obligation at beginning of year	$	(220.5	)		$	(245.0	)	$	(191.1	)	$	(181.4	)
	Service cost	(1.0		)		(1.2		)	(6.8		)	(5.1		)
	Interest cost	(9.2		)		(8.4		)	(6.1		)	(6.1		)
	Actuarial (loss) gain	(29.4		)		20.2			(25.8		)	(0.4		)
	Benefits paid	14.4				13.9			10.3			10.2
	Settlement	29.6				—			—			—
	Foreign currency exchange rate changes	—				—			25.3			(8.3		)
	Projected benefit obligation at end of year	(216.1		)		(220.5		)	(194.2		)	(191.1		)
	Change in plan assets
	Fair value of plan assets at beginning of year	177.4				180.5			4.2			4
	Actual return on plan assets	17.2				5.7			—			—
	Employer contributions	1.5				5.1			11.9			10.1
	Settlement	(29.6		)		—			—			—
	Foreign currency exchange rate changes	—				—			(0.7		)	0.3
	Benefits paid	(14.4		)		(13.9		)	(10.3		)	(10.2		)
	Fair value of plan assets at end of year	152.1				177.4			5.1			4.2
	Funded status — plan assets less than benefit obligations	(64.0		)		(43.1		)	(189.1		)	(186.9		)
	Recognized in accumulated other comprehensive income:
	Net actuarial loss (gain)	18.4				(16.9		)	18.4			(0.1		)
	Amounts not yet recognized as a component of net postretirement benefit cost	$	36.3			$	17.9		$	49.6		$	31.2
	Amounts recorded in the balance sheet:
	Accrued benefit liability — current	$	(0.6	)		$	(0.7	)	$	(8.1	)	$	(8.8	)
	Accrued benefit liability — long-term	(63.4		)		(42.4		)	(181.0		)	(178.1		)
	Accumulated other comprehensive loss	36.3				17.9			49.6			31.2
	Net amount recognized	$	(27.7	)		$	(25.2	)	$	(139.5	)	$	(155.7	)
	The accumulated benefit obligation of the U.S. plans was $215.6 million and $220.1 million as of December 31, 2014 and 2013, respectively. The accumulated benefit obligation of the non-U.S. plans was $182.7 million and $189.8 million as of December 31, 2014 and 2013, respectively.
	Set forth below is a detail of the net periodic pension and other post-retirement benefit expense for the defined benefit plans for the years ended December 31:
		Pension Benefits
		U.S. Plans
		2014				2013			2012
	Service cost	$	1			$	1.2		$	1.1
	Interest cost	9.2				8.4			9.3
	Amortization of unrecognized net loss	1.4				0.3			1.5
	Expected return on plan assets	(10.7		)		(9.4		)	(10.4		)
	Settlement charge	3.2				—			—
	Net periodic benefit cost	4.1				0.5			1.5
	Net loss (gain) arising during the year	22.1				(16.1		)	1.3
	Net gain recognized during the year	(3.6		)		(0.8		)	(3.4		)
	Total recognized in other comprehensive loss	18.5				(16.9		)	(2.1		)
	Total recognized in net periodic benefit cost and other comprehensive loss	$	22.6			$	(16.4	)	$	(0.6	)
	Set forth below is a detail of the net periodic pension and other post-retirement benefit expense for the defined benefit plans for the years ended December 31:
		Pension Benefits
		Non-U.S. Plans
		2014				2013			2012
	Service cost	$	6.8			$	5.1		$	4
	Interest cost	6.1				6.1			7.6
	Amortization of unrecognized net loss	1.6				1.8			0.8
	Net periodic benefit cost	14.5				13			12.4
	Net loss arising during the year	25.8				0.3			29.8
	Net gain recognized during the year	(1.6		)		(1.8		)	(0.8		)
	Exchange rate gain (loss) gain	(5.8		)		1.4			0.8
	Total recognized in other comprehensive loss	18.4				(0.1		)	29.8
Total recognized in net periodic benefit cost and other comprehensive loss	$	32.9			$	12.9		$	42.2
Future pension benefit payments expected to be paid are as follows:
	Pension
Expected benefit payments	U.S. Plans				Non-U.S. Plans
2015	$	14.4			$	10.7
2016	$	14.1			$	12.1
2017	$	14			$	12.3
2018	$	13.9			$	12
2019	$	13.8			$	10.4
2020-2024	$	67.6			$	51.4
Pension benefit payments for the U.S. pension plans are made from assets of the pension plans. We expect to contribute $0.7 million to our U.S. pension plans in 2015. Expected contributions are dependent on many variables, including the variability of the market value of the assets as compared to the obligation and other market or regulatory conditions. Accordingly, actual funding may differ significantly from current estimates. We expect to make annual benefit payments of approximately $10.7 million related to our non-U.S. pension plans in 2015.
The amounts in Accumulated other comprehensive income (loss) that are expected to be recognized as components of net periodic benefit cost during 2015 are as follows:
	U.S. Plans				Non-U.S. Plans			Total
Net actuarial loss	$	0.9			$	2.6		$	3.5
The following weighted-average assumptions were used to determine the Company’s pension benefit obligations for the year ended December 31:
	2014		2013
U.S. Plans
Discount rate — EPT Active Plans	3.70%		4.60%
Discount rate — EPT Inactive Plans	3.50%		4.40%
Discount rate — Divested Business Plans	3.50%		4.30%
Expected return on pension plan assets — EPT Active Plans	6.30%		6.50%
Expected return on pension plan assets — EPT Inactive Plans	6.30%		6.50%
Expected return on pension plan assets — Divested Business Plans	6.30%		6.50%
Rate of increases in compensation — EPT Active Plans	3.50%		3.50%
Non U.S. Plans
Discount rate	2.00%		3.50%
Rate of increases in compensation	2.5% – 3.0%		2.5% – 3.0%
The following weighted-average assumptions were used to determine the Company’s net periodic pension benefit costs for the year ended December 31:
	2014		2013
U.S. Plans
Discount rate — EPT Active Plans	4.60%		3.70%
Discount rate — EPT Inactive Plans	4.40%		3.50%
Discount rate — Divested Business Plans	4.30%		3.40%
Expected return on pension plan assets — EPT Active Plans	6.50%		7.00%
Expected return on pension plan assets — EPT Inactive Plans	6.50%		4.70%
Expected return on pension plan assets — Divested Business Plans	6.50%		6.00%
Non U.S. Plans
Discount rate	3.50%		3.50%
Expected return on pension plan assets	3.50%		3.70%
Our investment objective for defined benefit plan assets is to meet the plan’s benefit obligations, without undue exposure to risk. The investment strategy focuses on asset class diversification, liquidity to meet benefit payments and an appropriate balance of long-term investment return and risk. The Investment Committee oversees the investment allocation process, which includes the selection and evaluation of the investment manager, the determination of investment objectives and risk guidelines, and the monitoring of actual investment performance. In determining the expected long-term rate of return on defined benefit pension plan assets, management considers the historical rates of return over a period of time that is consistent with the long-term nature of the underlying obligations of these plans, the nature of investments and an expectation of future investment strategies.
We utilize the services of independent third-party investment managers to oversee the management of U.S. pension plan assets. The investment managers are allowed to exercise investment discretion, subject to limitations established by the Company.
Below are our actual and established target allocations for the EPT pension plans, representing 93% of U.S. pension plan assets:
	Actual			Target
	Allocation			Allocation
U.S. equity securities	11	%		11	%
Non-U.S. equity securities	11	%		11	%
Fixed income	62	%		62	%
High yield	5	%		5	%
TIPS	5	%		5	%
Global REITS	5	%		5	%
Cash	1	%		1	%
Total assets	100	%		100	%
Active plan investments include U.S. equity securities which are invested broadly in U.S. companies in various industries using the Wilshire 5000 Index as the asset class benchmark. Non-U.S. equity securities are invested broadly in non-U.S. companies in various industries using the MSCI ACWI ex-U.S. Index as the asset class benchmark. Long duration fixed income consists primarily of investment grade corporate fixed income bonds benchmarked against the Barclays Capital Long Credit Index. Intermediate government fixed income consists of U.S. government bonds using the Barclays Capital Intermediate Government Index as the asset class benchmark. U.S. Treasury Inflation Protected Fixed Income (“TIPS”) invests in the U.S. Treasury inflation protected securities market using the Barclays U.S. TIPS Index as the asset class benchmark. Global REITS investments are invested in the broad global real estate securities market with the FTSE EPRA/NAREIT Developed RE Index (or other comparable index) as the asset class benchmark. High Yield Fixed Income (“High yield”) invests in broad U.S. non-investment grade fixed income bonds using the Merrill Lynch U.S. High Yield Master II as the asset class benchmark.
Our asset allocations by asset category for the Divested business and non-U.S. plans are as follows:
	December 31,
	2014			2013
U.S. equity securities	33	%		38	%
Corporate bonds	8	%		10	%
Government bonds	11	%		10	%
Other fixed income	15	%		13	%
Non-U.S. assets	31	%		27	%
Cash	2	%		2	%
Total assets	100	%		100	%
Equity securities are invested broadly in U.S. companies in various industries. Non-U.S. assets consist of equity securities of non-U.S. companies in various industries as well as foreign mutual funds.
The fair value measurements of defined benefit pension plan assets by category at December 31, 2014 are as follows:
	December 31,				Quoted Prices in			Significant			Significant
					Active Markets			Other			Unobservable
					for Identical			Observable
Category	2014				Assets (Level 1)			Inputs (Level 2)			Inputs (Level 3)
Equity securities — US	$	21.2			$	3.9		$	17.3		$	—
Equity securities — Non US	15.4				—			15.4			—
Fixed income:
Bonds	88.6				—			88.6			—
Other fixed income	4.3				—			4.3			—
High yield	7.2				—			7.2			—
TIPS	6.7				—			6.7			—
Global REITS	7				—			7			—
Non-U.S. assets	5.1				—			5.1			—
Cash and cash equivalents	1.7				1.7			—			—
Total	$	157.2			$	5.6		$	151.6		$	—
Equity securities and fixed income, high-yield, TIPS and Global REITS investments are primarily comprised of mutual funds and common/collective trust funds. Investments in mutual funds and common/collective trust funds are valued at the net asset value per share or unit multiplied by the number of shares or units held as of the measurement date.
The defined benefit pension plans do not have any direct ownership of the Company’s common stock.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss)
	(a) Changes in Accumulated Comprehensive Income (Loss) by Component
		Foreign				Unrealized			Pension and			Pension and		Accumulated
		Currency				Gains and			Post-Retirement			Post-Retirement		Other
		Translation Loss				Losses on Cash Flow Hedging			Obligation			Obligation Tax Impact		Comprehensive
						Derivatives								Income (Loss)
	Beginning balance at	$	(5.5	)		$	(0.2	)	$	(49.1	)	$	9.6	$	(45.2	)
	1-Jan-14
	Other comprehensive (loss) income before reclassifications	(81.7		)		—			(42.0		)	5.7		(118.0		)
	Amounts reclassified from accumulated other comprehensive income (loss)	—				0.2			5.2			—		5.4
	Net current-period other comprehensive (loss) income	(81.7		)		0.2			(36.8		)	5.7		(112.6		)
	Ending balance at	$	(87.2	)		$	—		$	(85.9	)	$	15.3	$	(157.8	)
	31-Dec-14
	(b) Reclassifications out of Accumulated Other Comprehensive Income (loss)
	Details about Accumulated Other Comprehensive Income (loss) Components	Amounts Reclassified from Accumulated Other Comprehensive Income (loss)			Affected Line Item in the Statement Where Net Income is Presented
	Unrealized gains and losses on cash flow hedging derivatives	0.2			Cost of goods sold
	Pension and post-retirement obligation	5.2			Cost of goods sold

Earnings_Per_Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share
	The following table sets forth the computation of basic and dilutive loss per common share from continuing operations attributable to OM Group, Inc. common stockholders for the years ended December 31:
		2014			2013			2012
	Amounts attributable to OM Group, Inc. common stockholders:
	(in millions, except per share amounts)
	Loss from continuing operations, net of tax	$	(172.3	)	$	(71.7	)	$	(38.3	)
	Loss per common share - basic:
	Loss from continuing operations	$	(5.54	)	$	(2.27	)	$	(1.21	)
	Loss per common share - assuming dilution:
	Loss from continuing operations	$	(5.54	)	$	(2.27	)	$	(1.21	)
	Weighted average shares outstanding — basic	31.1			31.6			31.9
	Dilutive effect of stock options and restricted stock	—			—			—
	Weighted average shares outstanding — assuming dilution	31.1			31.6			31.9
	The following table sets forth the computation of basic and diluted net loss per common share attributable to OM Group, Inc. common stockholders for the years ended December 31:
		2014			2013			2012
	Amounts attributable to OM Group, Inc. common stockholders:
	(in millions, except per share amounts)
	Net loss	$	(172.6	)	(84.0		)	$	(38.7	)
	Loss per common share - basic:
	Net loss	$	(5.55	)	$	(2.66	)	$	(1.22	)
	Loss per common share - assuming dilution:
	Net loss	$	(5.55	)	$	(2.66	)	$	(1.22	)
	Weighted average shares outstanding — basic	31.1			31.6			31.9
	Dilutive effect of stock options and restricted stock	—			—			—
	Weighted average shares outstanding — assuming dilution	31.1			31.6			31.9
	We use the treasury stock method to calculate the effect of outstanding share-based compensation awards, which requires the computation of total employee proceeds as the sum of (a) the amount the employee must pay upon exercise of the award, (b) the amount of unearned share-based compensation costs attributed to future services and (c) the amount of tax benefits, if any, that would be credited to additional paid-in capital assuming exercise of the award. Shares, under share-based compensation awards, for which the total employee proceeds exceed the average market price over the applicable period have an anti-dilutive effect on earnings per share, and accordingly, are excluded from the calculation of diluted earnings per share.
	In the years ended December 31, 2014 and 2013, stock options to purchase 0.1 million shares and 0.1 million shares, respectively, of common stock were excluded from the calculation of dilutive earnings per share because the options’ exercise prices were greater than the average market price of the common shares and, therefore, the effect would have been anti-dilutive. As we had a loss from continuing operations for the years presented above, the effect of including dilutive securities in the earnings per share calculation would have been anti-dilutive. Accordingly, all shares under share-based compensation awards were excluded from the calculation of loss from continuing operations attributable to OM Group, Inc. common stockholders assuming dilution and net loss attributable to OM Group, Inc. common stockholders assuming dilution.

ShareBased_Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2014
Share-based Compensation [Abstract]
Share-Based Compensation	Share-Based Compensation
	On May 13, 2014, our stockholders approved the 2014 Equity and Incentive Compensation Plan (the “2014 Plan”). The 2014 Plan supersedes and replaces the 2007 Incentive Compensation Plan (the “2007 Plan”), which terminated upon the approval of the 2014 Plan. No further grants may be made under the 2007 plan.  The termination of the 2007 Plan will not impact outstanding awards issued as part of the 2007 Plan.
	Under the 2014 Plan, we may provide equity-based compensation in the form of stock options, stock appreciation rights (or SARs), restricted stock, restricted stock units (or RSUs), performance shares, performance units, dividend equivalents and other stock or stock-based awards to selected employees and non-employee directors.   The 2014 Plan also provides for the issuance of common stock to non-employee directors as all or part of their annual compensation for serving as directors, as may be determined by the board of directors.
	The total number of shares of common stock available for awards under the 2014 Plan (including any annual stock issuances made to non-employee directors) is 2,550,000.  Awards other than stock options and SARs will be counted against the aggregate share limit as 1.79 shares of common stock.  Under the 2014 Plan, no more than 1,424,581 shares of common stock could be issued in settlement of restricted stock unit (“RSU”) awards.  In addition, no person will be granted (i) stock options or SARs, in the aggregate, for more than 400,000 shares of common stock during any calendar year or (ii) awards of restricted stock, RSUs, performance shares or other stock-based awards intended to qualify as “qualified performance-based compensation” under Section 162(m) of the Internal Revenue Code, in the aggregate, for more than 400,000 shares of common stock during any calendar year.
	The 2014 Plan and the 2007 Plan provide that all options granted must have an exercise price of not less than the per share fair market value on the date of grant and that no option may have a term of more than ten years. We satisfy stock option exercises and restricted stock awards through the issuance of authorized but unissued shares or treasury shares.
	Set forth below is a summary of share-based compensation expense for option grants, restricted stock awards and restricted stock unit awards included as a component of Selling, general and administrative expenses in the Statements of Consolidated Operations for the year ended December 31:
		2014				2013				2012
	Stock options and restricted stock awards	$	6.5			$	5.4			$	5
	Restricted stock unit awards	0.6				0.3				0.2
	Share-based compensation expense - employees	$	7.1			$	5.7			$	5.2
	Share-based compensation expense - non-employee directors	$	0.5			$	0.5			$	0.5
	No tax benefit for share-based compensation was realized during 2014, 2013 or 2012 as a result of the valuation allowance against U.S. deferred tax assets.
	At December 31, 2014, there was $6.3 million of unrecognized compensation expense related to unvested share-based awards. That cost is expected to be recognized as follows: $4.6 million in 2015, $1.6 million in 2016 and $0.1 million in 2017 as a component of Selling, general and administrative expenses. Unearned compensation expense is recognized over the vesting period for the particular grant. Total unrecognized compensation cost will be adjusted for future changes in actual and estimated forfeitures, updated vesting assumptions for the performance awards, and fluctuations in the fair value of restricted stock unit awards.
	Our non-employee directors are paid a portion of their annual retainer in unrestricted shares of common stock which are valued as of the last trading date of the quarter. For purposes of determining the number of shares of common stock to be issued prior to May 13, 2014, the 2007 plan provides that shares are to be valued at the average of the high and low sale price of the Company’s common stock on the New York Stock Exchange ("NYSE"). Pursuant to the 2007 plan we issued 7,084 shares in the six months ended June 30, 2014 and 18,069 shares and 23,752 shares in the 12 months ended December 31, 2013 and 2012, respectively, to non-employee directors. For purposes of determining the number of shares of common stock to be issued subsequent to May 13, 2014, the 2014 plan provides that shares are to be valued at the closing sale price of the Company’s common stock on the NYSE. Pursuant to the 2014 plan, we issued 8,795 shares in the 12 months ended December 31, 2014.
	Stock Options
	Options granted generally vest in equal increments over a three-year period from the grant date. Upon any change in control of the Company, as defined in the applicable plan, or upon death, disability or retirement, the stock options become 100% vested and exercisable. We account for options that vest over more than one year as one award and recognize expense related to those awards on a straight-line basis over the vesting period.
	During 2014, 2013 and 2012, we granted stock options to purchase 230,300, 273,200 and 238,319 shares of common stock, respectively. Included in the 2012 grants are stock options to purchase 4,419 shares of common stock with a vesting period of one year, which were granted to our Chief Executive Officer (“CEO”) in connection with achievement of financial performance criteria in 2011 under our then high-performance incentive plan.
	The fair value of options was estimated at the date of grant using a Black-Scholes options pricing model with the following weighted-average assumptions:
			2014				2013				2012
	Risk-free interest rate		1.9		%		1.1		%		1.1		%
	Dividend yield		0.9		%		—				—
	Volatility factor of Company common stock		56		%		54		%		55		%
	Weighted-average expected option term (years)		6				6				6
	Weighted-average grant-date fair value		$	15.03			$	13.49			$	15.29
	The risk-free interest rate assumption is based upon the U.S. Treasury yield curve appropriate for the term of the options being valued. The dividend yield assumption was ninety-four hundredths for the awards in 2014 due to the initiation of a dividend by the Company. The dividend assumption was previously zero based on the historical expectation of retaining earnings for use in operations at the time of the award issuances in 2013 and 2012. Expected volatilities are based on historical volatility of our common stock. The expected term of options granted is determined using the simplified method allowed by Staff Accounting Bulletin (“SAB”) No. 110 as historical data was not sufficient to provide a reasonable estimate. Under this approach, the expected term is presumed to be the mid-point between the vesting date and the end of the contractual term.
	The following table sets forth the number of option shares and weighted-average grant-date fair value:
			Shares			Weighted-Average
						Fair Value at
						Grant Date
	Non-vested at December 31, 2012		442,626			$	17.2
	Granted during 2013		273,200			13.49
	Vested during 2013		(214,816	)		17.37
	Forfeited during 2013		(64,983	)		16.02
	Non-vested at December 31, 2013		436,027			14.78
	Granted during 2014		230,300			15.03
	Vested during 2014		(218,532	)		15.18
	Forfeited during 2014		(26,581	)		14.74
	Non-vested at December 31, 2014		421,214			$	14.36
	A summary of our stock option activity for 2014 is as follows:
			Shares			Weighted				Weighted		Aggregate
						Average				Average		Intrinsic
						Exercise				Remaining		Value
						Price				Contractual
										Term
	Outstanding at January 1, 2014		1,308,573			$	34.81
	Granted		230,300			32.06
	Exercised		(18,764	)		28.03
	Expired unexercised		(36,201	)		38.91
	Forfeited		(26,581	)		29.96
	Outstanding at December 31, 2014		1,457,327			$	32.97			5.4		$	7.9
	Vested or expected to vest at December 31, 2014		1,431,451			$	33.04			5.4		$	7.7
	Exercisable at December 31, 2014		1,042,314			$	34.3			4.2		$	4.4
	The fair value of options that vested during 2014, 2013 and 2012 was $3.3 million, $3.7 million and $3.5 million, respectively. The intrinsic value of options exercised in 2014 and 2013 was $0.1 million and $1.2 million, respectively. No stock options were exercised in 2012. The intrinsic value of an option represents the amount by which the market value of the stock exceeds the exercise price of the option.
	We received cash payments of $0.5 million and $2.8 million in 2014 and 2013, respectively, in connection with the exercise of stock options previously granted. The Company does not settle stock options for cash.
	Restricted Stock
	We issue restricted stock and, beginning in 2012, issue stock-settled restricted stock units to our employees in the U.S (“Restricted Stock," and "US-Based RSUs," respectively). We issue restricted stock units to employees outside the U.S. ("International RSUs"). Certain of the Restricted Stock, US-Based RSUs, and International RSU awards contain time-based vesting conditions and certain of the awards contain performance-based vesting conditions.
	The Restricted Stock and US-Based RSU awards are in all cases settled in our common stock. The value of the Restricted Stock and US-Based RSU awards are based upon the market price of an unrestricted share of our common stock at the date of grant. We recognize compensation expense ratably over the requisite performance period based upon the number of awards that are anticipated to vest. The number of awards anticipated to vest is evaluated quarterly and compensation expense is adjusted accordingly. We may withhold shares issued upon vesting if directed by individual employees as a means of meeting minimum statutory tax withholding requirements. We hold the surrendered shares as treasury stock.
	The International RSUs are settled in a cash payment that is based on the market price of an unrestricted share of our common stock at the vesting date. Since the awards will be settled in cash, they are treated as a liability award in accordance with the “Stock Compensation” topic of the ASC and are presented as a component of Other non-current liabilities on the Consolidated Balance Sheets. During the vesting period we remeasure the fair value of the International RSUs at each reporting date until the award is settled. Fluctuations in the fair value of the International RSUs are recorded as increases or decreases to compensation expense. Over the life of these awards, the cumulative amount of compensation expense recognized will match the actual cash paid.
	Performance-Based Awards
	During 2014, 2013 and 2012, we awarded 206,225, 245,950 and 130,500 shares, respectively, of performance-based Restricted stock to U.S. employees and 24,175, 35,150, and 33,450 performance-based International RSUs, respectively, to employees outside the U.S. (collectively "Performance-Based Awards").
	The number of Performance-Based Awards that ultimately vest is based upon our achievement of specific measurable financial performance criteria. A recipient of Performance-Based Awards may earn a total award ranging from 0% to 100% of the initial grant, with the target being 50% of the initial grant. The Performance-Based Awards granted during 2013 and 2014 will vest upon the satisfaction of established performance criteria based on average return on net assets and the performance of our share price as compared to the performance of the Russell 2000 unweighted index over a three-year performance period ending December 31, 2015 and 2016, respectively.
	The performance period for Performance-Based Awards granted during 2012 ended on December 31, 2014. The vesting of these awards was based on the achievement of consolidated EBITDA margin percentage measured against a predetermined peer group, and average return on net assets, in each case over three-year performance periods ending December 31, 2014. Based upon our performance against the stated performance objectives, 4% of the Performance-Based Awards granted in 2012 remain available to vest, or roughly 3,927 shares of Restricted Stock and 548 International RSUs. Vesting is conditional on approval from the Compensation Committee that the performance objectives were satisfied. The Compensation Committee makes this determination in the first quarter of 2015.
	The performance period for Performance-Based Awards granted during 2011 ended on December 31, 2013. The vesting of these awards was based on the achievement of consolidated EBITDA margin percentage (as defined above) measured against a predetermined peer group, and average return on net assets, in each case over three-year performance periods ending December 31, 2013. Based upon our performance against the stated performance objectives, 20% of the Performance-Based Awards granted in 2011 vested, or roughly 18,194 shares of Restricted Stock and 850 International RSUs. The Compensation Committee approved this vesting in the first quarter of 2014.
	Upon any change in control of the Company, as defined in the plan, the Performance-Based Awards under the terms of the award agreements vest at the target level. In the event of retirement, death, or disability, a pro rata number of Performance-Based Awards shall remain eligible for vesting at the end of the performance period.
A summary of our Performance-Based Awards for 2014 is as follows:
		International Restricted Stock Units			US Shares of Restricted Stock			Weighted
								Average
								Grant Date
								Fair Value
Non-vested at January 1, 2014		61,250			435,090			$	29.56
Granted		24,175			206,225			32.2
Vested		(850	)		(18,194	)		36.51
Forfeited		(12,183	)		(125,617	)		33.63
Non-vested at December 31, 2014		72,392			497,504			$	29.37
Expected to vest as of December 31, 2014		9,516			57,189
For awards granted prior to 2011, no performance-based shares vested and were issued in 2014, 2013 or 2012.
Time-Based Awards
In 2014, 2013 and 2012 we awarded 18,525, 60,000 and 69,327 time-based restricted stock units (RSUs); in 2012 we issued 20,000 shares of time-based restricted stock, respectively (collectively "US Time-Based Awards"). Included in the 2012 grant are 2,177 units of time-based awards with a vesting period of one year, which were granted to our Chief Executive Officer ("CEO") in connection with achievement of financial performance criteria under our then high performance annual incentive program. The value of the restricted stock units and restricted stock awarded in 2014, 2013 and 2012, based upon the market price of an unrestricted share of our common stock at the date of grant, was $0.6 million, $1.5 million and $2.6 million, respectively. During 2014, 2013 and 2012, we also awarded 6,050, 7,950, and 17,060 Time-Based International RSUs, respectively.
The US Time-Based Awards and Time-Based International RSUs have similar terms and vest three years from the date of grant, subject to the recipient remaining employed by the Company on that date. Upon any change in control of the Company, as defined in the plan, or upon retirement, the Time-Based Awards become 100% vested. A pro rata number of Time-Based Awards will vest in the event of death or disability prior to the stated vesting date.
A summary of our Time-Based awards for 2014 is as follows:
		Time-Based International RSUs			Shares of US Time-Based Awards			Weighted Average Grant Date Fair Value - US Time-Based Awards
Non-vested at January 1, 2014		16,330			180,560			$	29.26
Granted - three year vesting		6,050			18,525			32.17
Vested		(6,220	)		(50,895	)		35.99
Forfeitures		(1,085	)		(13,020	)		29.63
Non-vested at December 31, 2014		15,075			135,170			$	27.08
Expected to vest as of December 31, 2014		13,967			130,174
The following US Time-Based Awards vested and were issued in the respective years ended December 31:
		2014			2013			2012
Vested - three year vesting period		50,895			54,300			22,100
Vested -one year vesting period		—			2,177			2,767
Shares surrendered to pay withholding taxes		(18,069	)		(19,645	)		(8,538	)
Net shares issued		32,826			36,832			16,329

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies
	We have potential contingent liabilities with respect to environmental matters related to our former operations in Brazil which were sold in 2003. Environmental cost-sharing arrangements are in place between the original owner and operator of these operations and between the Company and the subsequent purchaser of these operations. We have reviewed the limited information made available to us on the environmental conditions and are awaiting more detailed information from the purchaser. We cannot currently evaluate whether or not, or to what extent, we will be responsible for any remediation costs until more detailed information is received and validated.
	From time to time, we are subject to various legal and regulatory proceedings, claims and assessments that arise in the normal course of business. The ultimate resolution of such proceedings, claims and assessments is inherently unpredictable and, as a result, our estimates of liability, if any, are subject to change and actual results may materially differ from such estimates. Our estimate of any costs to be incurred as a result of these proceedings, claims and assessments are accrued when the liability is considered probable and the amount can be reasonably estimated. We believe the amount of any current potential liability with respect to legal and regulatory proceedings, claims and assessments will not have a material adverse effect upon our financial condition, results of operations, or cash flows.

Lease_Obligations

Lease Obligations	12 Months Ended
	Dec. 31, 2014
Leases, Operating [Abstract]
Lease Obligations	Lease Obligations
	We rent office space, equipment, and land under long-term operating leases. Our operating lease expense was $8.0 million in 2014, $8.8 million in 2013 and $9.6 million in 2012.
	Future minimum payments under noncancellable operating leases at December 31, 2014 are as follows for the years ending December 31:
	2015	$	6.6
	2016	6
	2017	5.1
	2018	3.4
	2019	2.1
	Thereafter	8.2
	Total minimum lease payments	$	31.4

Reportable_Segments_and_Geogra

Reportable Segments and Geographic Information	12 Months Ended
	Dec. 31, 2014
Segment Reporting Information, Profit (Loss) [Abstract]
Reportable Segments and Geographic Information	Reportable Segments and Geographic Information
	We determine our segments based on how the chief operating decision maker makes decisions about allocating resources to segments and measuring their performance. We operate and report our results in four operating segments: Magnetic Technologies, Battery Technologies, Specialty Chemicals and Advanced Materials. Intersegment transactions are immaterial and generally recognized based on current market prices and are eliminated in consolidation. Corporate is comprised of general and administrative expenses not allocated to the operating segments.
	The Magnetic Technologies segment develops, manufactures and distributes differentiated, high-performance industrial-use magnetic materials and related products and systems with exceptional magnetic and/or physical properties for a wide array of end markets, including automotive systems, electrical installation technology, energy conversion and distribution, industrial, retail and renewable energy.
	The Specialty Chemicals segment develops, produces and supplies chemicals for electronic applications; industrial applications including coatings, composites and tire; and photomasks used by customers to produce semiconductors and related products.
	The Battery Technologies segment provides advanced batteries, battery management systems, battery-related research and energetic devices for defense, space, medical and commercial markets.
	The Advanced Materials segment manufactured inorganic products using unrefined cobalt and other metals and served the mobile energy storage, renewable energy, automotive systems, construction and mining, and industrial end markets.
	The following table reflects the results of our reportable segments:
			2014			2013			2012
	Net sales
	Magnetic Technologies		$	495		$	522.6		$	631.6
	Specialty Chemicals (e)		316.1			318.6			323.6
	Battery Technologies		153.8			150.3			143
	Advanced Materials		102.6			166.3			447
	Intersegment items		—			(0.3		)	(0.8		)
			$	1,067.50		$	1,157.50		$	1,544.40
	Operating profit (loss)
	Magnetic Technologies (a)(b)(c)		$	(177.1	)	$	22.4		$	(22.3	)
	Specialty Chemicals (a)(b)(d)(e)		31.3			35.8			34.5
	Battery Technologies (a)(b)		19.9			21.8			19.6
	Advanced Materials		(5.6		)	(0.4		)	6.4
	Corporate(a)(b)(f)		(33.6		)	(38.5		)	(42.9		)
			(165.1		)	41.1			(4.7		)
	Interest expense		$	(2.6	)	$	(12.3	)	$	(49.7	)
	Foreign exchange gain (loss)		(6.5		)	8			(0.8		)
	Gain (loss) on divestiture of Advance Materials business		1.7			(111.6		)	—
	Other income (expense), net		(0.3		)	12			6.6
			(7.7		)	(103.9		)	(43.9		)
	Loss from continuing operations before income taxes		(172.8		)	(62.8		)	(48.6		)
	Expenditures for property, plant & equipment
	Magnetic Technologies		$	26.5		$	30.8		$	27.3
	Specialty Chemicals (e)		3.1			7.6			4.9
	Battery Technologies		4.5			5.3			5.8
	Advanced Materials		—			6.3			29.6
	Corporate		0.4			3.1			—
			$	34.5		$	53.1		$	67.6
	Depreciation and amortization
	Magnetic Technologies		$	42.2		$	44.2		$	40.8
	Specialty Chemicals (e)		14			14.8			15.7
	Battery Technologies		10.5			10.1			10.1
	Advanced Materials		—			3.9			16.9
	Corporate		0.8			0.9			0.8
			$	67.5		$	73.9		$	84.3
	Total assets
	Magnetic Technologies		$	675		$	1,020.60
	Specialty Chemicals (e)		396.3			416.5
	Battery Technologies		265.9			237.4
	Advanced Materials		10.6			17.9
	Corporate		71.7			90.7
			$	1,419.50		$	1,783.10
	(a)	The year ended December 31, 2014 includes a $195.4 million goodwill and intangible asset non-cash impairment charge in Magnetic Technologies. The results also include costs related to cost optimization and other business improvement initiatives of $1.9 million in Magnetic Technologies, $2.6 million in Battery Technologies, $2.1 million in Specialty Chemicals, and $0.2 million in Corporate, respectively. Cost reduction initiatives include headcount reductions, minor facility consolidation, supply chain optimization, corporate cost reductions, and other structural changes. There was also a $3.2 million non-cash pension settlement charge in Battery Technologies during the fourth quarter.
	(b)	The year ended December 31, 2013 includes charges related to cost reduction initiatives of $5.4 million in Magnetic Technologies, $0.8 million in Battery Technologies, $1.1 million in Specialty Chemicals and $2.4 million in Corporate, respectively.
	(c)	Includes $55.9 million of charges related to the VAC inventory purchase accounting step-up and LCM charges in 2012.
	(d)	Includes property sale gains of $2.9 million in 2012.
	(e)	All results related to the UPC business are excluded from the Specialty Chemicals segment for all periods presented.
	(f)	Includes a $2.5 million non-cash pension settlement charge to certain participants in one of our U.S. defined benefit pension plans in 2012.
			Net Sales(a)(c)			Long-Lived
						Assets(b)(c)
	Geographic Region Information
	2014
	Germany		544.3			217.5
	United States		263.3			76.1
	Finland		102.6			—
	Other		157.3			14.7
			$	1,067.50		$	308.3
2013
Germany		$	571.9		$	247.9
United States		296.2			79.5
Finland		102.6			—
Japan		29.3			—
Other		157.5			18.2
		$	1,157.50		$	345.6
2012
Germany		$	681.4
United States		324.9
Finland		229.7
Japan		161.7
Other		146.7
		$	1,544.40
(a)	Net sales attributed to the geographic area are based on the location of the manufacturing facility, except for Japan, which was a sales office and included in the divestiture of the Advance Materials business.
(b)	Long-lived assets consists of property, plant and equipment, net.
(c)	All results and balances related to the UPC business are excluded for all periods presented.

Quarterly_Results_of_Operation

Quarterly Results of Operations (Unaudited)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Quarterly Results of Operations (Unaudited)	Quarterly Results of Operations (Unaudited)
	The sum of the quarter income (loss) per common share does not agree to the full year information due to the difference in weighted average share values between quarter to date and year to date calculations.
		2014
		First			Second			Third			Fourth			Full Year
		Quarter			Quarter			Quarter			Quarter
	Net sales	$	261.7		$	297.5		$	262.9		$	245.4		$	1,067.50
	Gross profit	$	61.9		$	63.1		$	62.6		$	50.6		$	238.2
	Amounts attributable to OM Group, Inc. common stockholders:
	Income (loss) from continuing operations, net of tax	$	5.3		$	5.1		$	6.3		$	(189.0	)	$	(172.3	)
	Income (loss) from discontinued operations, net of tax	(0.1		)	(0.3		)	0.1			—			$	(0.3	)
	Net income (loss)	$	5.2		$	4.8		$	6.4		$	(189.0	)	$	(172.6	)
	Net income (loss) per common share — basic
	Continuing operations	$	0.17		$	0.16		$	0.2		$	(6.24	)	$	(5.54	)
	Discontinued operations	—			(0.01		)	0.01			—			(0.01		)
	Net income (loss)	$	0.17		$	0.15		$	0.21		$	(6.24	)	$	(5.55	)
	Net income (loss) per common share — assuming dilution
	Continuing operations	$	0.16		$	0.16		$	0.2		$	(6.24	)	$	(5.54	)
	Discontinued operations	—			(0.01		)	—			—			(0.01		)
	Net income (loss)	$	0.16		$	0.15		$	0.2		$	(6.24	)	$	(5.55	)
	The second quarter 2014 includes costs related to cost reduction initiatives of $0.4 million in Specialty Chemicals.
	The third quarter 2014 includes costs related to cost optimization and other business improvement initiatives of $0.3 million in Magnetic Technologies, $2.6 million in Battery Technologies, $1.0 million in Specialty Chemicals, and $0.1 million in Corporate, respectively.
	The fourth quarter 2014 includes a $195.4 million goodwill and intangible asset non-cash impairment charge in Magnetic Technologies. The fourth quarter 2014 also includes costs related to cost optimization and other business improvement initiatives of $1.6 million in Magnetic Technologies, $0.7 million in Specialty Chemicals, and $0.1 million in Corporate, respectively. There was also a $3.2 million non-cash pension settlement charge in Battery Technologies during the fourth quarter.
		2013
		First			Second			Third			Fourth			Full Year
		Quarter			Quarter			Quarter			Quarter
	Net sales	$	341.8		$	279.5		$	265.7		$	270.5		$	1,157.50
	Gross profit	$	74.2		$	63.8		$	65.9		$	54.6		$	258.4
	Amounts attributable to OM Group, Inc. common stockholders:
	Income (loss) from continuing operations, net of tax	$	(109.5	)	$	8.1		$	12.4		$	17.3		$	(71.7	)
	Income (loss) from discontinued operations, net of tax	(0.5		)	(11.4		)	(0.3		)	(0.1		)	(12.3		)
	Net income (loss)	$	(110.0	)	$	(3.3	)	$	12.1		$	17.2		$	(84.0	)
	Net income (loss) per common share — basic
	Continuing operations	$	(3.47	)	$	0.26		$	0.4		$	0.54		$	(2.27	)
	Discontinued operations	(0.02		)	(0.36		)	(0.01		)	—			(0.39		)
	Net income (loss)	$	(3.49	)	$	(0.10	)	$	0.39		$	0.54		$	(2.66	)
	Net income (loss) per common share — assuming dilution
	Continuing operations	$	(3.46	)	$	0.26		$	0.39		$	0.54		$	(2.27	)
	Discontinued operations	(0.02		)	(0.36		)	(0.01		)	—			(0.39		)
	Net income (loss)	$	(3.48	)	$	(0.10	)	$	0.38		$	0.54		$	(2.66	)
	2013 results related to the UPC business are excluded from the Special Chemicals segment for all periods presented.
	The first quarter 2013 includes a $111.6 million loss on the divestiture of the Advanced Materials business. The first quarter of 2013 also includes costs related to cost reduction initiatives of $3.8 million in Magnetic Technologies and $0.2 million in Battery Technologies.
	The second quarter of 2013 includes a $9.8 million loss on the disposal of the UPC business recorded within Income (loss) from discontinued operations. The second quarter of 2013 also includes costs related to cost reduction initiatives of $0.4 million in Magnetic Technologies, $0.5 million in Battery Technologies, and $1.1 million in Specialty Chemicals.
	The third quarter of 2013 includes costs related to cost reduction initiatives of $0.7 million in Magnetic Technologies, $0.1 million in Battery Technologies and $1.0 million in Corporate.
	The fourth quarter of 2013 includes a $13.0 million reduction of contingent consideration related to Rahu. The fourth quarter of 2013 includes costs related to cost reduction initiatives of $0.4 million in Magnetic Technologies and $1.4 million in Corporate.

Subsequent_Events

Subsequent Events	12 Months Ended
	Dec. 31, 2014
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events
	On February 18, 2015, we announced a wide-ranging set of competitive repositioning and cost optimization opportunities throughout the enterprise that are expected to improve our ability to serve customers, better compete in global markets and deliver stronger financial performance. The opportunities include headcount reductions across the enterprise; site consolidations; relocation of certain operations to improve our cost structure and better serve customers; better alignment of various research and development, marketing and technical activities with customers’ next generation products and applications; and further corporate cost reductions.
	Over the next three years, we expect to incur total cash expenses related to these opportunities of approximately $50.0 - $65.0 million. We also anticipate annualized savings of $30.0 - $40.0 million by the end of 2017, which are expected to ramp up starting in late 2015. Certain of these opportunities will take place in Europe and are subject to negotiations with employee works councils and unions, which could impact the timing and scope of the expected expenses and savings. We expect that the cost of these opportunities will not have a material impact on our financial position or liquidity and will be funded by operating cash flows and borrowing on our revolving line of credit when necessary.

Schedule_II_Valuation_and_Qual

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2014
Valuation and Qualifying Accounts [Abstract]
Schedule II - Valuation and Qualifying Accounts	Schedule II — Valuation and Qualifying Accounts
	Years Ended December 31, 2014, 2013 and 2012
			Balance at		Acquisition / Divestitures				Charged			Charged				Deductions				Balance at
			Beginning of Year						(Credited) to			(Credited) to								End of Year
	Classifications								Costs and Expenses			Other Accounts
	2014
	Allowance for doubtful accounts		$	3.9	—				$	0.3	-1	$	(1.2	)	-9	$	(0.5	)	-4	$	2.5
	Allowance for note receivable		19.1		—				—		-1	(16.7		)	-8	—				2.4
	Environmental reserve		2.3		—				0.2		-3	—				(0.7		)	-5	1.8
			$	25.3	$	—			$	0.5		$	(17.9	)		$	(1.2	)		$	6.7
	2013
	Allowance for doubtful accounts		$	5.2	$	(1.0	)	-7	$	0.2	-1	$	(0.2	)	-6	$	(0.3	)	-4	$	3.9
	Allowance for note receivable		3.1		—				16		-2	—				—				19.1
	Environmental reserve		2.4		—				0.3		-3	—			-6	(0.4		)	-5	2.3
			$	10.7	$	(1.0	)		$	16.5		$	(0.2	)		$	(0.7	)		$	25.3
	2012
	Allowance for doubtful accounts		$	4.8	$	—			$	0.7	-1	$	0.1		-6	$	(0.4	)	-4	$	5.2
	Allowance for note receivable		3.1		—				—		-1	—				—				3.1
	Environmental reserve		2.6		—				0.3		-3	—			-6	(0.5		)	-5	2.4
			$	10.5	$	—			$	1		$	0.1			$	(0.9	)		$	10.7
	_______________________________________
	-1	Provision for uncollectible accounts and notes receivable included in selling, general and administrative expenses.
	-2	Note receivable fully reserved at time of sale of cobalt business on March 29, 2013.
	-3	Provision for environmental costs included in selling, general and administrative expenses.
	-4	Actual accounts written-off against the allowance.
	-5	Actual cash expenditures charged against the accrual.
	-6	Foreign currency translation adjustment.
	-7	Resulting from sale of AM and UPC businesses during 2013.
	-8	Relief of note receivable obligation in accordance with compliance on the cobalt supply agreement.
	-9	Foreign currency translation adjustment and minor balance sheet reclassification.

Significant_Accounting_Policie1

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation — OM Group, Inc. (the “Company”, “we”, “our”, “us”) is a technology-driven industrial company serving attractive global markets, including automotive systems, electronic devices, aerospace and defense, industrial and medical. We use innovative technologies to address customers' complex applications and demanding requirements. Our strategy is to grow organically through product and application innovation and new market and customer development, to grow strategically through complementary acquisitions to build-out our growth platforms, and to maximize total stockholder returns through a combination of business growth, financial discipline, optimal deployment of capital and continued operational excellence. Our objective is to deliver sustainable, profitable growth and create long-term stockholder value. The consolidated financial statements include the accounts of OM Group and its consolidated subsidiaries. We were formed in 1991 as a Delaware Corporation. Intercompany accounts and transactions have been eliminated in consolidation.
	Certain financial data may have been rounded. As a result of such rounding, the totals of data presented in this document may vary slightly from the actual arithmetical totals of such data.
Use of Estimates	Use of Estimates - The preparation of financial statements, in conformity with US generally accepted accounting policies ("US GAAP"), requires management to make estimates and assumptions in certain circumstances that affect the amounts reported in the accompanying consolidated financial statements and notes. Actual results could differ from these estimates
Cash Equivalents	Cash Equivalents - All highly-liquid investments, with a maturity of three months or less when purchased, are considered to be cash equivalents
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts - We have recorded an allowance for doubtful accounts to record accounts receivable at their estimated net realizable value. The allowance is based upon an analysis of historical bad debts, a review of the aging of accounts receivable and the current creditworthiness of customers. Accounts are written off against the allowance when it becomes probable that collections will not occur. Trade credit is generally extended on a short-term basis and accounts receivable generally do not bear interest
Inventories	Inventories - Magnetic Technologies' inventories are valued using the average cost method. Cost of sales under the average cost method represents the weighted average cost of the items sold. We believe the average cost method provides for a better matching of inventory costs with related sales based on Magnetic Technologies' manufacturing process. Our remaining inventory is valued using First in, First out (FIFO). Inventory costs include raw materials, labor and manufacturing overhead. Inventory accounted for under the percentage-of-completion method is included in work-in-process inventory and represents accumulated contract costs less the portion of such costs allocated to delivered units. The costs attributed to units delivered are based on the estimated average cost of all units expected to be produced on a contract-by-contract basis.
	Changes in the price of rare earth and other materials can have a significant impact on inventory valuation. We evaluate the need for a lower of cost or market (“LCM”) adjustment to inventories based on the selling prices of our finished products generally at the end of the period. To the extent raw material prices increase subsequent to the balance sheet date, we consider these price movements in our LCM evaluation. Declines in the selling prices of our finished goods, which can result from decreases in the market price of raw materials or other factors, can result in our inventory carrying value being written down to a lower market value.
Property, Plant and Equipment	Property, Plant and Equipment - Property, plant and equipment is recorded at historical cost less accumulated depreciation. Depreciation of plant and equipment, including assets recorded under capital leases, is provided by the straight-line method over the useful lives of 5 to 25 years for land improvements, 5 to 40 years for buildings and improvements, 5 to 15 years for machinery and equipment (with the majority in the range of 5 to 10 years), 5 to 10 years for furniture and fixtures and 3 to 5 years for vehicles and computers and related equipment. Leasehold improvements are depreciated over the shorter of the estimated useful life or the term of the lease.
Long-lived Assets other than Goodwill	Long-lived Assets other than Goodwill - Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate the carrying amount may not be recoverable. Events or circumstances that would result in an impairment review primarily include operating losses, a significant change in the use of an asset, or the planned disposal or sale of the asset. The asset would be considered impaired when the future net undiscounted cash flows generated by the asset are less than its carrying value. An impairment loss would be recognized based on the amount by which the carrying value of the asset exceeds its estimated fair value.
Goodwill and Intangible Assets	Goodwill and Intangible Assets - We evaluate the carrying value of goodwill and indefinite-lived intangible assets for impairment annually as of October 1 and between annual evaluations if changes in circumstances or the occurrence of certain events indicate potential impairment. If the carrying value of goodwill or an indefinite-lived intangible asset exceeds its fair value, an impairment loss is recognized.
	Intangible assets consist of (i) definite-lived assets subject to amortization and (ii) indefinite-lived intangible assets not subject to amortization. Definite-lived intangible assets consist principally of customer relationships, developed technology, know-how, capitalized software and license agreements and are being amortized using the straight-line or other appropriate method, if applicable. Indefinite-lived intangible assets consist of tradenames.
Retained Liabilities of Business Sold	Retained Liabilities of Businesses Sold - Retained liabilities of businesses sold include obligations related to our former Precious Metals Group (“PMG”), which was sold in 2003. Under terms of the sale agreement, we will reimburse the buyer of this business for certain items that become due and payable by the buyer subsequent to the sale date. Such items are principally comprised of taxes payable related to periods during which we owned PMG.
Revenue Recognition	Revenue Recognition — Except for revenue recognized under the percentage of completion method of accounting in Battery Technologies (see discussion below), we recognize revenue when persuasive evidence of an arrangement exists, unaffiliated customers take title and assume risk of loss, the sales price is fixed or determinable and collection of the related receivable is reasonably assured. Revenue recognition generally occurs upon shipment of product or usage of inventory consigned to customers. All amounts in a sales transaction billed to a customer related to shipping and handling are reported as sales.
	The Battery Technologies segment uses the percentage of completion method to recognize most of its revenue. Most defense contracts use the units-of-delivery method while most space contracts use the cost-to-cost method as the basis to measure progress toward completing a contract. Under the units-of-delivery method, revenues are recognized based on the contract price of units delivered. Under the cost-to-cost method, revenue is recognized based on the ratio of cost incurred compared to management's estimate of total costs expected to be incurred under the contract. The percentage of completion method requires substantial judgment on the part of management due to the duration of the contracts as well as the technical nature of the products involved. Contract revenues and cost estimates are reviewed at least quarterly and adjustments are reflected in the accounting period such amounts are determined. Billings in excess of amounts earned are deferred. Anticipated losses on contracts are recorded in full in the period in which the loss becomes evident.
Cost of Goods Sold	Cost of Goods Sold — Cost of goods sold is comprised of raw material costs, direct production, maintenance and utility costs, depreciation, other overhead costs and shipping and handling costs.
Research and Development	Research and Development — Research and development costs are charged to expense when incurred, are included in selling, general and administrative expenses and amounted to $26.0 million, $26.3 million and $32.2 million in 2014, 2013 and 2012, respectively. These amounts do not include development and application engineering costs incurred in conjunction with fulfilling customer orders and executing projects.
Accounting for Operating Leases	Accounting for Operating Leases — Lease expense is recorded on a straight-line basis. The noncancellable lease term used to calculate the amount of the straight-line expense is generally determined to be the initial lease term, including any optional renewal terms that are reasonably assured. Certain leases include escalating rent provisions and lease incentives which are recognized as lease expense on a straight-line basis over the lease term. Lease payments that depend on an existing index or rate are included in our minimum lease payments that are recognized as lease expense on a straight-line basis over the minimum lease term.
Income Taxes	Income Taxes — Deferred income taxes are provided to recognize the effect of temporary differences between financial and tax reporting. Deferred income taxes are not provided for undistributed earnings of foreign consolidated subsidiaries, to the extent such earnings are determined to be reinvested for an indefinite period of time.
Foreign Currency Translation	Foreign Currency Translation — The functional currency for most of our operating subsidiaries outside of the United States is the applicable local currency. For those operations, assets and liabilities are translated into U.S. dollars at period-ending exchange rates and revenues and expenses are translated into U.S. dollars using average exchange rates. The resulting translation adjustments are recorded as a component of Accumulated other comprehensive income (loss) in stockholders’ equity. Accordingly, foreign currency exchange gains and losses related to assets, liabilities and transactions denominated in other currencies (principally the Euro) are included in the Statements of Consolidated Operations.
Derivative Instruments	Derivative Instruments — We enter into derivative instruments and hedging activities to manage, where possible and economically efficient, commodity price risk, foreign currency exchange rate risk and interest rate risk related to borrowings. It is our policy to execute such instruments with creditworthy banks and not enter into derivative instruments for speculative purposes. All derivatives are reflected at their fair value and recorded in other current assets and other current liabilities as of December 31, 2013. There were no outstanding derivatives as of December 31, 2014. The accounting for the fair value of a derivative depends upon whether it has been designated as a hedge and on the type of hedging relationship. To qualify for designation in a hedging relationship, specific criteria must be met and appropriate documentation prepared. Changes in the fair values of derivatives not designated in a hedging relationship are recognized in earnings.
	From time to time we employ derivative instruments in connection with purchases and sales of inventory in order to establish a fixed margin and mitigate the risk of price volatility. Some customers request fixed pricing and we may use a derivative to mitigate price risk. While this hedging may limit our ability to participate in gains from favorable commodity price fluctuations, it eliminates the risk of loss from adverse commodity price fluctuations.
	Periodically, we enter into certain derivative instruments designated as cash flow hedges. For these hedges, the effective portion of the gain or loss from the financial instrument is initially reported as a component of Accumulated other comprehensive income (loss) in stockholders’ equity and subsequently reclassified into earnings in the same line as the hedged item in the same period or periods during which the hedged item affects earnings.

Inventories_Tables

Inventories (Tables)	12 Months Ended
	Dec. 31, 2014
Inventory, Net [Abstract]
Schedule of Inventory	Inventories consist of the following as of December 31,
		2014		2013
	Raw materials and supplies	$	73.6	$	83.3
	Work-in-process	118.1		122.2
	Finished goods	36.7		35.4
		$	228.4	$	240.9

Property_Plant_and_Equipment_n1

Property, Plant and Equipment, net (Tables)	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment, Net [Abstract]
Property, Plant and Equipment	Property, plant and equipment, net consists of the following as of December 31,
		2014			2013
	Land and improvements	$	37.6		$	39.6
	Buildings and improvements	138			145.8
	Machinery and equipment	346.4			350.4
	Furniture and fixtures	8.2			7.6
	Property, plant and equipment, at cost	530.2			543.4
	Less accumulated depreciation	(221.9		)	(197.8		)
		$	308.3		$	345.6

Acquisitions_and_Divestitures_

Acquisitions and Divestitures (Tables)	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
Schedule of Disposal Groups, Including Discontinued Operations, Income Statement, Balance Sheet and Additional Disclosures	A summary of our discontinued operations activity is as follows:
		Twelve Months Ended December 31
	(In millions except per share data)		2014			2013			2012
	Net Sales		$	—		$	38.3		$	93.4
	Loss from operations of divested business (net of tax)		$	(0.1	)	$	(2.5	)	$	(0.4	)
	Loss on disposal of business (net of tax)		(0.2		)	(9.8		)	—
	Loss from discontinued operations (net of tax)		$	(0.3	)	$	(12.3	)	$	(0.4	)
	Loss per share from discontinued operations (net of tax)
	Basic and diluted		$	(0.01	)	$	(0.39	)	$	(0.01	)

Goodwill_and_Other_Intangible_1

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Change in the carrying amount of goodwill	The change in the carrying amount of goodwill is as follows:
		Magnetic Technologies			Advanced			Specialty			Battery			Continuing Operations			Discontinued Operations			Consolidated
					Materials			Chemicals			Technologies
	Balance at January 1, 2013	$	205.2		$	103.3		$	154.4		$	65.4		$	528.4		$	15		$	543.4
	Divestitures and adjustments	—			(103.3		)	—			—			(103.3		)	(15.0		)	(118.3		)
	Foreign currency translation adjustments	9.3			—			(1.3		)	(0.3		)	7.7			—			7.7
	Balance at December 31, 2013	214.5			—			153.1			65.1			432.7			—			432.7
	Impairment	(168.7		)	—			—			—			(168.7		)	—			(168.7		)
	Acquisition	—			—			—			14.5			14.5			—			14.5
	Foreign currency translation adjustments	(19.3		)	—			(6.3		)	(0.3		)	(25.9		)	—			(25.9		)
	Balance at December 31, 2014	$	26.5		$	—		$	146.8		$	79.3		$	252.6		$	—		$	252.6
Summary of intangible assets	A summary of intangible assets follows:
		2014												2013
		Carrying Value			Accumulated			Impairment			Net			Carrying Value			Accumulated			Net
					Amortization (a)												Amortization (a)
	Tradenames	$	114.1		$	(9.6	)	$	(26.7	)	$	77.8		$	117		$	(2.9	)	$	114.1
	Customer relationships	218.2			(90.1		)	—			128.1			234.5			(82.4		)	152.1
	Developed technology	135.5			(36.1		)	—			99.4			136.5			(19.9		)	116.6
	Know-how	20.1			(4.6		)	—			15.5			18.6			(3.6		)	15
	Capitalized software	22.3			(18.6		)	—			3.7			22			(17.4		)	4.6
	Other intangibles	2.9			(2.6		)	—			0.3			4.2			(3.6		)	0.6
	Total	$	513.1		$	(161.6	)	$	(26.7	)	$	324.8		$	532.8		$	(129.8	)	$	403
	(a) - Actual amounts of amortization expense may differ from the estimated amounts due to changes in foreign currency exchange rates, impairment of intangible assets, intangible assets additions, accelerated amortization of intangible assets, acquisitions and divestitures and other factors.

Derivative_Instruments_Tables

Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 2014
Derivative Instruments and Hedges, Assets [Abstract]
Effect of Derivative Instruments	The following table summarizes the effect of derivative instruments as recorded in the Statement of Consolidated Operations:
	Derivatives in Cash Flow Hedging Relationships
		Amount of Gain (Loss) on Derivative Recognized in AOCI(L) (Effective Portion) for the Year Ended December 31,
		2014				2013				2012
	Euro forward contracts	$	—			$	—			$	6
	Commodity contracts	—				(0.3		)		—
	Interest rate swap agreements	—				—				(0.1		)
	Total	$	—			$	(0.3	)		$	5.9
		Location of Gain (Loss) Reclassified		Amount of Gain (Loss) Reclassified from
		from AOCI(L) into Income		AOCI(L) into Income (Effective Portion)
				for the Year Ended December 31,
		(Effective Portion)		2014				2013				2012
	Euro forward contracts	Cost of goods sold		$	—			$	—			$	2.3
	Commodity contracts	Cost of goods sold		(0.2		)		(0.2		)		—
	Interest rate swap agreements	Interest expense		—				—				(0.4		)
	Total			$	(0.2	)		$	(0.2	)		$	1.9

Fair_Value_Disclosures_Tables

Fair Value Disclosures (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Assets and Liabilities Accounted for at Fair Value on a Recurring Basis	The following table shows the Company’s assets and liabilities accounted for at fair value on a recurring basis:
					Fair Value Measurements at Reporting Date Using
					Quoted Prices in	Significant Other	Significant
					Active Markets for	Observable Inputs	Unobservable Inputs
					Identical Assets
	Description	December 31, 2014			(Level 1)	(Level 2)	(Level 3)
	Liabilities:
	Contingent consideration payable	$	1.4		—	—	1.4
Schedule of Changes in Level 3 Liabilities Measure at Fair Value on a Recurring Basis	The following table summarizes changes in Level 3 liabilities measure at fair value on a recurring basis:
		Contingent Consideration
	Fair Value at December 31, 2013	$	1.4
	Accretion expense	0.2
	Foreign exchange	(0.2		)
	Fair Value at December 31, 2014	$	1.4

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income (Loss) From Continuing Operations Before Income Tax Expense	Loss from continuing operations before income tax expense consists of the following:
			Year Ended December 31
			2014			2013			2012
	United States		$	(9.0	)	$	(13.6	)	$	(12.3	)
	Outside the United States		(163.8		)	(49.2		)	(36.3		)
			$	(172.8	)	$	(62.8	)	$	(48.6	)
Income Tax Expense	Income tax (benefit) expense is summarized as follows:
			Year Ended December 31
			2014			2013			2012
	Current tax provision (benefit):
	United States:
	Federal		$	1.4		$	0.6		$	(3.1	)
	State and local		0.2			—			—
	Outside the United States		15.1			17.4			30.1
	Total current		16.7			18			27
	Deferred tax provision (benefit):
	United States		(1.4		)	0.6			2.4
	Outside the United States		(15.8		)	(7.9		)	(32.6		)
	Total deferred		(17.2		)	(7.3		)	(30.2		)
			$	(0.5	)	$	10.7		$	(3.2	)
Company's Effective Income Tax Rates	A reconciliation of income taxes computed using the United States statutory rate to income taxes computed using our effective income tax rate is as follows:
			Year Ended December 31
			2014			2013			2012
	Loss from continuing operations before income tax expense		$	(172.8	)	$	(62.8	)	$	(48.6	)
	Income taxes at the United States statutory rate (35)%		(60.5		)	(21.9		)	(17.1		)
	Increase (decrease) in taxes resulting from:
	Effective tax rate differential on income outside of the United States		—			19.3			(3.3		)
	Repatriation of foreign earnings		2.3			(1.7		)	7.4
	Goodwill impairment		52.1			—			—
	Valuation allowance		6.7			13.2			3.7
	Uncertain tax positions		(1.1		)	0.1			(1.9		)
	Allowance on GTL prepaid tax asset		—			0.4			5.6
	Other, net		—			1.3			2.4
	Income tax expense (benefit)		$	(0.5	)	$	10.7		$	(3.2	)
	Effective income tax rate		(a)			(a)			6.5		%
	(a)	not meaningful
Schedule of Deferred Income Taxes	Significant components of our deferred income taxes are as follows:
			December 31
			2014			2013
	Employee benefit accruals		$	58.6		$	44.7
	Foreign operating loss carryforwards		6.5			8.3
	Foreign tax credit carryforwards		17.3			23.1
	State operating loss carryforwards		7.8			7.6
	Operating accruals		48.4			42.3
	Investment credit carryforwards		2.6			3.3
	Valuation allowance		(91.9		)	(83.6		)
	Deferred tax assets		49.3			45.7
	Depreciation		(31.2		)	(37.5		)
	Amortization		(88.5		)	(107.7		)
	Other		(0.2		)	(1.0		)
	Deferred tax liabilities		(119.9		)	(146.2		)
	Net deferred tax liabilities		$	(70.6	)	$	(100.5	)
	Deferred income taxes are recorded in the Consolidated Balance Sheets in the following accounts:
			December 31
			2014			2013
	Other current assets		$	2.1		$	2.4
	Other non-current assets		5.3			6.4
	Other current liabilities		(3.2		)	(6.8		)
	Deferred income taxes — non-current liabilities		(74.8		)	(102.5		)
			$	(70.6	)	$	(100.5	)
Reconciliation of Uncertain Tax Positions	A reconciliation of the beginning and ending amount of uncertain tax positions is as follows:
	Balance at January 1, 2013		$	18
	Additions for tax positions related to the current year		0.6
	Reductions for tax positions of prior years		(3.4		)
	Foreign currency translation		0.3
	Balance at December 31, 2013		15.5
	Additions for tax positions related to the current year		0.4
	Addition of receivable for prior year tax position		(0.7		)
	Reductions for tax positions of prior years		(0.6		)
	Reductions for lapses of statute of limitations		(0.1		)
	Foreign currency translation		(0.8		)
	Balance at December 31, 2014		$	13.7

Pension_and_Other_PostRetireme1

Pension and Other Post-Retirement Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2014
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Schedule of changes in benefit obligation and plan assets, funded status and amounts recognized in Consolidated Balance Sheets	The following table sets forth the changes in the benefit obligation and the plan assets during the year and reconciles the funded status of the defined benefit plans with the amounts recognized in the Consolidated Balance Sheet at December 31:
		Pension Benefits
		U.S. Plans							Non-U.S. Plans
		2014				2013			2014			2013
	Change in benefit obligation
	Projected benefit obligation at beginning of year	$	(220.5	)		$	(245.0	)	$	(191.1	)	$	(181.4	)
	Service cost	(1.0		)		(1.2		)	(6.8		)	(5.1		)
	Interest cost	(9.2		)		(8.4		)	(6.1		)	(6.1		)
	Actuarial (loss) gain	(29.4		)		20.2			(25.8		)	(0.4		)
	Benefits paid	14.4				13.9			10.3			10.2
	Settlement	29.6				—			—			—
	Foreign currency exchange rate changes	—				—			25.3			(8.3		)
	Projected benefit obligation at end of year	(216.1		)		(220.5		)	(194.2		)	(191.1		)
	Change in plan assets
	Fair value of plan assets at beginning of year	177.4				180.5			4.2			4
	Actual return on plan assets	17.2				5.7			—			—
	Employer contributions	1.5				5.1			11.9			10.1
	Settlement	(29.6		)		—			—			—
	Foreign currency exchange rate changes	—				—			(0.7		)	0.3
	Benefits paid	(14.4		)		(13.9		)	(10.3		)	(10.2		)
	Fair value of plan assets at end of year	152.1				177.4			5.1			4.2
	Funded status — plan assets less than benefit obligations	(64.0		)		(43.1		)	(189.1		)	(186.9		)
	Recognized in accumulated other comprehensive income:
	Net actuarial loss (gain)	18.4				(16.9		)	18.4			(0.1		)
	Amounts not yet recognized as a component of net postretirement benefit cost	$	36.3			$	17.9		$	49.6		$	31.2
	Amounts recorded in the balance sheet:
	Accrued benefit liability — current	$	(0.6	)		$	(0.7	)	$	(8.1	)	$	(8.8	)
	Accrued benefit liability — long-term	(63.4		)		(42.4		)	(181.0		)	(178.1		)
	Accumulated other comprehensive loss	36.3				17.9			49.6			31.2
	Net amount recognized	$	(27.7	)		$	(25.2	)	$	(139.5	)	$	(155.7	)
Future pension benefit payments expected to be paid	Future pension benefit payments expected to be paid are as follows:
		Pension
	Expected benefit payments	U.S. Plans				Non-U.S. Plans
	2015	$	14.4			$	10.7
	2016	$	14.1			$	12.1
	2017	$	14			$	12.3
	2018	$	13.9			$	12
	2019	$	13.8			$	10.4
	2020-2024	$	67.6			$	51.4
Schedule of amounts in accumulated other comprehensive income (loss) expected to be recognized during 2012	The amounts in Accumulated other comprehensive income (loss) that are expected to be recognized as components of net periodic benefit cost during 2015 are as follows:
		U.S. Plans				Non-U.S. Plans			Total
	Net actuarial loss	$	0.9			$	2.6		$	3.5
Schedule of weighted-average assumptions used	The following weighted-average assumptions were used to determine the Company’s pension benefit obligations for the year ended December 31:
		2014		2013
	U.S. Plans
	Discount rate — EPT Active Plans	3.70%		4.60%
	Discount rate — EPT Inactive Plans	3.50%		4.40%
	Discount rate — Divested Business Plans	3.50%		4.30%
	Expected return on pension plan assets — EPT Active Plans	6.30%		6.50%
	Expected return on pension plan assets — EPT Inactive Plans	6.30%		6.50%
	Expected return on pension plan assets — Divested Business Plans	6.30%		6.50%
	Rate of increases in compensation — EPT Active Plans	3.50%		3.50%
	Non U.S. Plans
	Discount rate	2.00%		3.50%
	Rate of increases in compensation	2.5% – 3.0%		2.5% – 3.0%
	The following weighted-average assumptions were used to determine the Company’s net periodic pension benefit costs for the year ended December 31:
		2014		2013
	U.S. Plans
	Discount rate — EPT Active Plans	4.60%		3.70%
	Discount rate — EPT Inactive Plans	4.40%		3.50%
	Discount rate — Divested Business Plans	4.30%		3.40%
	Expected return on pension plan assets — EPT Active Plans	6.50%		7.00%
	Expected return on pension plan assets — EPT Inactive Plans	6.50%		4.70%
	Expected return on pension plan assets — Divested Business Plans	6.50%		6.00%
	Non U.S. Plans
	Discount rate	3.50%		3.50%
	Expected return on pension plan assets	3.50%		3.70%
Schedule of plan assets allocation	The fair value measurements of defined benefit pension plan assets by category at December 31, 2014 are as follows:
		December 31,				Quoted Prices in			Significant			Significant
						Active Markets			Other			Unobservable
						for Identical			Observable
	Category	2014				Assets (Level 1)			Inputs (Level 2)			Inputs (Level 3)
	Equity securities — US	$	21.2			$	3.9		$	17.3		$	—
	Equity securities — Non US	15.4				—			15.4			—
	Fixed income:
	Bonds	88.6				—			88.6			—
	Other fixed income	4.3				—			4.3			—
	High yield	7.2				—			7.2			—
	TIPS	6.7				—			6.7			—
	Global REITS	7				—			7			—
	Non-U.S. assets	5.1				—			5.1			—
	Cash and cash equivalents	1.7				1.7			—			—
	Total	$	157.2			$	5.6		$	151.6		$	—
U.S. Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Schedule of net benefit costs and amounts recognized in other comprehensive income (loss)	Set forth below is a detail of the net periodic pension and other post-retirement benefit expense for the defined benefit plans for the years ended December 31:
		Pension Benefits
		U.S. Plans
		2014				2013			2012
	Service cost	$	1			$	1.2		$	1.1
	Interest cost	9.2				8.4			9.3
	Amortization of unrecognized net loss	1.4				0.3			1.5
	Expected return on plan assets	(10.7		)		(9.4		)	(10.4		)
	Settlement charge	3.2				—			—
	Net periodic benefit cost	4.1				0.5			1.5
	Net loss (gain) arising during the year	22.1				(16.1		)	1.3
	Net gain recognized during the year	(3.6		)		(0.8		)	(3.4		)
	Total recognized in other comprehensive loss	18.5				(16.9		)	(2.1		)
	Total recognized in net periodic benefit cost and other comprehensive loss	$	22.6			$	(16.4	)	$	(0.6	)
EPT Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Schedule of plan assets allocation	Below are our actual and established target allocations for the EPT pension plans, representing 93% of U.S. pension plan assets:
		Actual			Target
		Allocation			Allocation
	U.S. equity securities	11	%		11	%
	Non-U.S. equity securities	11	%		11	%
	Fixed income	62	%		62	%
	High yield	5	%		5	%
	TIPS	5	%		5	%
	Global REITS	5	%		5	%
	Cash	1	%		1	%
	Total assets	100	%		100	%
Non-U.S. Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Schedule of net benefit costs and amounts recognized in other comprehensive income (loss)	Set forth below is a detail of the net periodic pension and other post-retirement benefit expense for the defined benefit plans for the years ended December 31:
		Pension Benefits
		Non-U.S. Plans
		2014				2013			2012
	Service cost	$	6.8			$	5.1		$	4
	Interest cost	6.1				6.1			7.6
	Amortization of unrecognized net loss	1.6				1.8			0.8
	Net periodic benefit cost	14.5				13			12.4
	Net loss arising during the year	25.8				0.3			29.8
	Net gain recognized during the year	(1.6		)		(1.8		)	(0.8		)
	Exchange rate gain (loss) gain	(5.8		)		1.4			0.8
	Total recognized in other comprehensive loss	18.4				(0.1		)	29.8
	Total recognized in net periodic benefit cost and other comprehensive loss	$	32.9			$	12.9		$	42.2
SCM and Non-U.S. Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Schedule of plan assets allocation	Our asset allocations by asset category for the Divested business and non-U.S. plans are as follows:
		December 31,
		2014			2013
	U.S. equity securities	33	%		38	%
	Corporate bonds	8	%		10	%
	Government bonds	11	%		10	%
	Other fixed income	15	%		13	%
	Non-U.S. assets	31	%		27	%
	Cash	2	%		2	%
	Total assets	100	%		100	%

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	Changes in Accumulated Comprehensive Income (Loss) by Component
		Foreign				Unrealized			Pension and			Pension and		Accumulated
		Currency				Gains and			Post-Retirement			Post-Retirement		Other
		Translation Loss				Losses on Cash Flow Hedging			Obligation			Obligation Tax Impact		Comprehensive
						Derivatives								Income (Loss)
	Beginning balance at	$	(5.5	)		$	(0.2	)	$	(49.1	)	$	9.6	$	(45.2	)
	1-Jan-14
	Other comprehensive (loss) income before reclassifications	(81.7		)		—			(42.0		)	5.7		(118.0		)
	Amounts reclassified from accumulated other comprehensive income (loss)	—				0.2			5.2			—		5.4
	Net current-period other comprehensive (loss) income	(81.7		)		0.2			(36.8		)	5.7		(112.6		)
	Ending balance at	$	(87.2	)		$	—		$	(85.9	)	$	15.3	$	(157.8	)
	31-Dec-14
	(b) Reclassifications out of Accumulated Other Comprehensive Income (loss)
	Details about Accumulated Other Comprehensive Income (loss) Components	Amounts Reclassified from Accumulated Other Comprehensive Income (loss)			Affected Line Item in the Statement Where Net Income is Presented
	Unrealized gains and losses on cash flow hedging derivatives	0.2			Cost of goods sold
	Pension and post-retirement obligation	5.2			Cost of goods sold

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Computation of Basic And Diluted Income Per Common Share From Continuing Operations	The following table sets forth the computation of basic and dilutive loss per common share from continuing operations attributable to OM Group, Inc. common stockholders for the years ended December 31:
		2014			2013			2012
	Amounts attributable to OM Group, Inc. common stockholders:
	(in millions, except per share amounts)
	Loss from continuing operations, net of tax	$	(172.3	)	$	(71.7	)	$	(38.3	)
	Loss per common share - basic:
	Loss from continuing operations	$	(5.54	)	$	(2.27	)	$	(1.21	)
	Loss per common share - assuming dilution:
	Loss from continuing operations	$	(5.54	)	$	(2.27	)	$	(1.21	)
	Weighted average shares outstanding — basic	31.1			31.6			31.9
	Dilutive effect of stock options and restricted stock	—			—			—
	Weighted average shares outstanding — assuming dilution	31.1			31.6			31.9
Computation of Basic And Diluted Net Income Per Common Share	The following table sets forth the computation of basic and diluted net loss per common share attributable to OM Group, Inc. common stockholders for the years ended December 31:
		2014			2013			2012
	Amounts attributable to OM Group, Inc. common stockholders:
	(in millions, except per share amounts)
	Net loss	$	(172.6	)	(84.0		)	$	(38.7	)
	Loss per common share - basic:
	Net loss	$	(5.55	)	$	(2.66	)	$	(1.22	)
	Loss per common share - assuming dilution:
	Net loss	$	(5.55	)	$	(2.66	)	$	(1.22	)
	Weighted average shares outstanding — basic	31.1			31.6			31.9
	Dilutive effect of stock options and restricted stock	—			—			—
	Weighted average shares outstanding — assuming dilution	31.1			31.6			31.9

ShareBased_Compensation_Tables

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2014
Share-based Compensation [Abstract]
Summary of Share-Based Compensation Expense	Set forth below is a summary of share-based compensation expense for option grants, restricted stock awards and restricted stock unit awards included as a component of Selling, general and administrative expenses in the Statements of Consolidated Operations for the year ended December 31:
		2014				2013				2012
	Stock options and restricted stock awards	$	6.5			$	5.4			$	5
	Restricted stock unit awards	0.6				0.3				0.2
	Share-based compensation expense - employees	$	7.1			$	5.7			$	5.2
	Share-based compensation expense - non-employee directors	$	0.5			$	0.5			$	0.5
Schedule of Share-Based Compensation Stock Options Valuation Assumptions	The fair value of options was estimated at the date of grant using a Black-Scholes options pricing model with the following weighted-average assumptions:
			2014				2013				2012
	Risk-free interest rate		1.9		%		1.1		%		1.1		%
	Dividend yield		0.9		%		—				—
	Volatility factor of Company common stock		56		%		54		%		55		%
	Weighted-average expected option term (years)		6				6				6
	Weighted-average grant-date fair value		$	15.03			$	13.49			$	15.29
Number of Options Shares and Weighted-Average Grant-Date Fair Value	The following table sets forth the number of option shares and weighted-average grant-date fair value:
			Shares			Weighted-Average
						Fair Value at
						Grant Date
	Non-vested at December 31, 2012		442,626			$	17.2
	Granted during 2013		273,200			13.49
	Vested during 2013		(214,816	)		17.37
	Forfeited during 2013		(64,983	)		16.02
	Non-vested at December 31, 2013		436,027			14.78
	Granted during 2014		230,300			15.03
	Vested during 2014		(218,532	)		15.18
	Forfeited during 2014		(26,581	)		14.74
	Non-vested at December 31, 2014		421,214			$	14.36
Summary of Stock Option Activity	A summary of our stock option activity for 2014 is as follows:
			Shares			Weighted				Weighted		Aggregate
						Average				Average		Intrinsic
						Exercise				Remaining		Value
						Price				Contractual
										Term
	Outstanding at January 1, 2014		1,308,573			$	34.81
	Granted		230,300			32.06
	Exercised		(18,764	)		28.03
	Expired unexercised		(36,201	)		38.91
	Forfeited		(26,581	)		29.96
	Outstanding at December 31, 2014		1,457,327			$	32.97			5.4		$	7.9
	Vested or expected to vest at December 31, 2014		1,431,451			$	33.04			5.4		$	7.7
	Exercisable at December 31, 2014		1,042,314			$	34.3			4.2		$	4.4
Summary of Performance-Based Restricted Stock Awards and Stock Unit Awards	A summary of our Performance-Based Awards for 2014 is as follows:
			International Restricted Stock Units			US Shares of Restricted Stock			Weighted
									Average
									Grant Date
									Fair Value
	Non-vested at January 1, 2014		61,250			435,090			$	29.56
	Granted		24,175			206,225			32.2
	Vested		(850	)		(18,194	)		36.51
	Forfeited		(12,183	)		(125,617	)		33.63
	Non-vested at December 31, 2014		72,392			497,504			$	29.37
	Expected to vest as of December 31, 2014		9,516			57,189
Schedule of Time-Based Restricted Stock Awards and Stock Unit Awards	A summary of our Time-Based awards for 2014 is as follows:
			Time-Based International RSUs			Shares of US Time-Based Awards			Weighted Average Grant Date Fair Value - US Time-Based Awards
	Non-vested at January 1, 2014		16,330			180,560			$	29.26
	Granted - three year vesting		6,050			18,525			32.17
	Vested		(6,220	)		(50,895	)		35.99
	Forfeitures		(1,085	)		(13,020	)		29.63
	Non-vested at December 31, 2014		15,075			135,170			$	27.08
	Expected to vest as of December 31, 2014		13,967			130,174
Schedule of Time-Based Shares Vested and Issued	The following US Time-Based Awards vested and were issued in the respective years ended December 31:
			2014			2013			2012
	Vested - three year vesting period		50,895			54,300			22,100
	Vested -one year vesting period		—			2,177			2,767
	Shares surrendered to pay withholding taxes		(18,069	)		(19,645	)		(8,538	)
	Net shares issued		32,826			36,832			16,329

Lease_Obligations_Tables

Lease Obligations (Tables)	12 Months Ended
	Dec. 31, 2014
Leases, Operating [Abstract]
Schedule of Future Minimum Payments Under Noncancellable Operating Leases	Future minimum payments under noncancellable operating leases at December 31, 2014 are as follows for the years ending December 31:
	2015	$	6.6
	2016	6
	2017	5.1
	2018	3.4
	2019	2.1
	Thereafter	8.2
	Total minimum lease payments	$	31.4

Reportable_Segments_and_Geogra1

Reportable Segments and Geographic Information (Tables)	12 Months Ended
	Dec. 31, 2014
Segment Reporting Information, Profit (Loss) [Abstract]
Results of Reportable Segments	The following table reflects the results of our reportable segments:
			2014			2013			2012
	Net sales
	Magnetic Technologies		$	495		$	522.6		$	631.6
	Specialty Chemicals (e)		316.1			318.6			323.6
	Battery Technologies		153.8			150.3			143
	Advanced Materials		102.6			166.3			447
	Intersegment items		—			(0.3		)	(0.8		)
			$	1,067.50		$	1,157.50		$	1,544.40
	Operating profit (loss)
	Magnetic Technologies (a)(b)(c)		$	(177.1	)	$	22.4		$	(22.3	)
	Specialty Chemicals (a)(b)(d)(e)		31.3			35.8			34.5
	Battery Technologies (a)(b)		19.9			21.8			19.6
	Advanced Materials		(5.6		)	(0.4		)	6.4
	Corporate(a)(b)(f)		(33.6		)	(38.5		)	(42.9		)
			(165.1		)	41.1			(4.7		)
	Interest expense		$	(2.6	)	$	(12.3	)	$	(49.7	)
	Foreign exchange gain (loss)		(6.5		)	8			(0.8		)
	Gain (loss) on divestiture of Advance Materials business		1.7			(111.6		)	—
	Other income (expense), net		(0.3		)	12			6.6
			(7.7		)	(103.9		)	(43.9		)
	Loss from continuing operations before income taxes		(172.8		)	(62.8		)	(48.6		)
	Expenditures for property, plant & equipment
	Magnetic Technologies		$	26.5		$	30.8		$	27.3
	Specialty Chemicals (e)		3.1			7.6			4.9
	Battery Technologies		4.5			5.3			5.8
	Advanced Materials		—			6.3			29.6
	Corporate		0.4			3.1			—
			$	34.5		$	53.1		$	67.6
	Depreciation and amortization
	Magnetic Technologies		$	42.2		$	44.2		$	40.8
	Specialty Chemicals (e)		14			14.8			15.7
	Battery Technologies		10.5			10.1			10.1
	Advanced Materials		—			3.9			16.9
	Corporate		0.8			0.9			0.8
			$	67.5		$	73.9		$	84.3
	Total assets
	Magnetic Technologies		$	675		$	1,020.60
	Specialty Chemicals (e)		396.3			416.5
	Battery Technologies		265.9			237.4
	Advanced Materials		10.6			17.9
	Corporate		71.7			90.7
			$	1,419.50		$	1,783.10
	(a)	The year ended December 31, 2014 includes a $195.4 million goodwill and intangible asset non-cash impairment charge in Magnetic Technologies. The results also include costs related to cost optimization and other business improvement initiatives of $1.9 million in Magnetic Technologies, $2.6 million in Battery Technologies, $2.1 million in Specialty Chemicals, and $0.2 million in Corporate, respectively. Cost reduction initiatives include headcount reductions, minor facility consolidation, supply chain optimization, corporate cost reductions, and other structural changes. There was also a $3.2 million non-cash pension settlement charge in Battery Technologies during the fourth quarter.
	(b)	The year ended December 31, 2013 includes charges related to cost reduction initiatives of $5.4 million in Magnetic Technologies, $0.8 million in Battery Technologies, $1.1 million in Specialty Chemicals and $2.4 million in Corporate, respectively.
	(c)	Includes $55.9 million of charges related to the VAC inventory purchase accounting step-up and LCM charges in 2012.
	(d)	Includes property sale gains of $2.9 million in 2012.
	(e)	All results related to the UPC business are excluded from the Specialty Chemicals segment for all periods presented.
	(f)	Includes a $2.5 million non-cash pension settlement charge to certain participants in one of our U.S. defined benefit pension plans in 2012.
Schedule of Geographic Information
			Net Sales(a)(c)			Long-Lived
						Assets(b)(c)
	Geographic Region Information
	2014
	Germany		544.3			217.5
	United States		263.3			76.1
	Finland		102.6			—
	Other		157.3			14.7
			$	1,067.50		$	308.3
	2013
	Germany		$	571.9		$	247.9
	United States		296.2			79.5
	Finland		102.6			—
	Japan		29.3			—
	Other		157.5			18.2
			$	1,157.50		$	345.6
	2012
	Germany		$	681.4
	United States		324.9
	Finland		229.7
	Japan		161.7
	Other		146.7
			$	1,544.40
	(a)	Net sales attributed to the geographic area are based on the location of the manufacturing facility, except for Japan, which was a sales office and included in the divestiture of the Advance Materials business.
	(b)	Long-lived assets consists of property, plant and equipment, net.
	(c)	All results and balances related to the UPC business are excluded for all periods presented.

Quarterly_Results_of_Operation1

Quarterly Results of Operations (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Results of Operations
		2014
		First			Second			Third			Fourth			Full Year
		Quarter			Quarter			Quarter			Quarter
	Net sales	$	261.7		$	297.5		$	262.9		$	245.4		$	1,067.50
	Gross profit	$	61.9		$	63.1		$	62.6		$	50.6		$	238.2
	Amounts attributable to OM Group, Inc. common stockholders:
	Income (loss) from continuing operations, net of tax	$	5.3		$	5.1		$	6.3		$	(189.0	)	$	(172.3	)
	Income (loss) from discontinued operations, net of tax	(0.1		)	(0.3		)	0.1			—			$	(0.3	)
	Net income (loss)	$	5.2		$	4.8		$	6.4		$	(189.0	)	$	(172.6	)
	Net income (loss) per common share — basic
	Continuing operations	$	0.17		$	0.16		$	0.2		$	(6.24	)	$	(5.54	)
	Discontinued operations	—			(0.01		)	0.01			—			(0.01		)
	Net income (loss)	$	0.17		$	0.15		$	0.21		$	(6.24	)	$	(5.55	)
	Net income (loss) per common share — assuming dilution
	Continuing operations	$	0.16		$	0.16		$	0.2		$	(6.24	)	$	(5.54	)
	Discontinued operations	—			(0.01		)	—			—			(0.01		)
	Net income (loss)	$	0.16		$	0.15		$	0.2		$	(6.24	)	$	(5.55	)
	The second quarter 2014 includes costs related to cost reduction initiatives of $0.4 million in Specialty Chemicals.
	The third quarter 2014 includes costs related to cost optimization and other business improvement initiatives of $0.3 million in Magnetic Technologies, $2.6 million in Battery Technologies, $1.0 million in Specialty Chemicals, and $0.1 million in Corporate, respectively.
	The fourth quarter 2014 includes a $195.4 million goodwill and intangible asset non-cash impairment charge in Magnetic Technologies. The fourth quarter 2014 also includes costs related to cost optimization and other business improvement initiatives of $1.6 million in Magnetic Technologies, $0.7 million in Specialty Chemicals, and $0.1 million in Corporate, respectively. There was also a $3.2 million non-cash pension settlement charge in Battery Technologies during the fourth quarter.
		2013
		First			Second			Third			Fourth			Full Year
		Quarter			Quarter			Quarter			Quarter
	Net sales	$	341.8		$	279.5		$	265.7		$	270.5		$	1,157.50
	Gross profit	$	74.2		$	63.8		$	65.9		$	54.6		$	258.4
	Amounts attributable to OM Group, Inc. common stockholders:
	Income (loss) from continuing operations, net of tax	$	(109.5	)	$	8.1		$	12.4		$	17.3		$	(71.7	)
	Income (loss) from discontinued operations, net of tax	(0.5		)	(11.4		)	(0.3		)	(0.1		)	(12.3		)
	Net income (loss)	$	(110.0	)	$	(3.3	)	$	12.1		$	17.2		$	(84.0	)
	Net income (loss) per common share — basic
	Continuing operations	$	(3.47	)	$	0.26		$	0.4		$	0.54		$	(2.27	)
	Discontinued operations	(0.02		)	(0.36		)	(0.01		)	—			(0.39		)
	Net income (loss)	$	(3.49	)	$	(0.10	)	$	0.39		$	0.54		$	(2.66	)
	Net income (loss) per common share — assuming dilution
	Continuing operations	$	(3.46	)	$	0.26		$	0.39		$	0.54		$	(2.27	)
	Discontinued operations	(0.02		)	(0.36		)	(0.01		)	—			(0.39		)
	Net income (loss)	$	(3.48	)	$	(0.10	)	$	0.38		$	0.54		$	(2.66	)

Significant_Accounting_Policie2

Significant Accounting Policies (Narrative) (Details) (USD $)	12 Months Ended			0 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Nov. 24, 2014	Mar. 29, 2013
Related Party Transaction [Line Items]
Percentage of interest in joint venture by the company					55.00%
Noncontrolling interest in joint venture					45.00%
Research and development costs included in selling, general and administrative expenses	$26	$26.30	$32.20
Accquirer of PMG [Member]
Related Party Transaction [Line Items]
Retained liabilities of PMG, net liability	11.3	12.3
Indemnification receivables	8.2	9.1
Battery Technologies [Member]
Related Party Transaction [Line Items]
Purchase price total cash consideration				$24.60

Significant_Accounting_Policie3

Significant Accounting Policies (Property, Plant and Equipment) (Details)	12 Months Ended
	Dec. 31, 2014
Minimum [Member] | Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life (in years)	5 years
Minimum [Member] | Buildings and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life (in years)	5 years
Minimum [Member] | Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life (in years)	5 years
Minimum [Member] | Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life (in years)	5 years
Minimum [Member] | Vehicles, Computers and Related Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life (in years)	3 years
Maximum [Member] | Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life (in years)	25 years
Maximum [Member] | Buildings and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life (in years)	40 years
Maximum [Member] | Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life (in years)	15 years
Maximum [Member] | Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life (in years)	10 years
Maximum [Member] | Vehicles, Computers and Related Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life (in years)	5 years
Majority Minimum [Member] | Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life (in years)	5 years
Majority Maximum [Member] | Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life (in years)	10 years

Inventories_Schedule_of_Invent

Inventories (Schedule of Inventories) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Inventory, Net [Abstract]
Raw materials and supplies	$73.60	$83.30
Work-in-process	118.1	122.2
Finished goods	36.7	35.4
Inventories, total	$228.40	$240.90

Property_Plant_and_Equipment_n2

Property, Plant and Equipment, net (Schedule of Property, Plant and Equipment) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	$530.20	$543.40
Less accumulated depreciation	-221.9	-197.8
Property, plant and equipment, net	308.3	345.6
Land and improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	37.6	39.6
Building and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	138	145.8
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	346.4	350.4
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	$8.20	$7.60

Property_Plant_and_Equipment_n3

Property, Plant and Equipment, net (Narrative) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Abstract]
Depreciation expense	$42.50	$47.70	$58.70

Acquisitions_and_Divestitures_1

Acquisitions and Divestitures (Narrative) (Details) (USD $)	12 Months Ended			0 Months Ended		3 Months Ended	0 Months Ended		1 Months Ended		0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 29, 2013	31-May-13	Jun. 30, 2014	Aug. 02, 2011	Aug. 02, 2011	Dec. 31, 2014	Aug. 31, 2013	Nov. 24, 2014
				contract
Business Acquisition [Line Items]
Purchase price of VAC payable to seller	$0	$11,300,000							$0
Payments for purchase price payable to seller	16,200,000	23,000,000	0
Loss on divestiture of advance materials business	1,700,000	-111,600,000	0
Advanced Materials [Member]
Business Acquisition [Line Items]
Cash proceeds from divestiture of businesses				328,700,000
Proceeds from divestiture of businesses, net of cash divested	0	328,700,000	0	302,100,000
Proceeds from divestiture of businesses				26,600,000
Loss on divestiture of advance materials business				-111,600,000
Write off of deferred debt issuance cost				10,300,000
Provision for doubtful accounts				16,000,000
Transaction expense				9,000,000
Gain contingency, unrecorded amount				110,000,000
Potential earn-out payment period				3 years
Number of agreements				2
Ultra Pure Chemicals [Member]
Business Acquisition [Line Items]
Proceeds from divestiture of businesses					63,300,000
Write off of deferred debt issuance cost					1,500,000
Transaction expense					1,000,000
Selling price, working capital adjustment					3,000,000
Loss on disposal of business (net of tax)	200,000	9,800,000	0		9,800,000	200,000
Gain on sale of net assets					1,500,000
Loss from discontinued operations, net of tax					8,800,000
Interest expense, debt repaid by proceeds from divestiture of business		1,000,000	2,500,000
VAC [Member]
Business Acquisition [Line Items]
Purchase price total cash consideration							812,200,000
Cash consideration paid for business acquisition							686,200,000
Purchase price of VAC payable to seller							86,300,000	86,300,000
Shares issued							39,700,000	39,700,000
Period from closing date of acquisition with certain exceptions related to tax matters								2 years
Payments for purchase price payable to seller									16,200,000	23,000,000
Reduction of purchase price payable to seller									1,600,000
Battery Technologies [Member]
Business Acquisition [Line Items]
Purchase price total cash consideration											24,600,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net											10,100,000
Intangible Assets, Net (Excluding Goodwill), Acquired During Period											5,500,000
Goodwill, Acquired During Period	$14,500,000										$14,500,000

Acquisitions_and_Divestitures_2

Acquisitions and Divestitures Summary of discontinued operations activity (Details) (USD $)	3 Months Ended								12 Months Ended			0 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	31-May-13
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss from operations of divested business (net of tax)	$0	$0.10	($0.30)	($0.10)	($0.10)	($0.30)	($11.40)	($0.50)	($0.30)	($12.30)	($0.40)
Loss from discontinued operations (net of tax)									-0.3	-12.3	-0.4
Basic (in dollars per share)	$0	$0.01	($0.01)	$0	$0	($0.01)	($0.36)	($0.02)	($0.01)	($0.39)	($0.01)
Ultra Pure Chemicals [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net Sales									0	38.3	93.4
Loss from operations of divested business (net of tax)									-0.1	-2.5	-0.4
Loss on disposal of business (net of tax)			-0.2						-0.2	-9.8	0	-9.8
Loss from discontinued operations (net of tax)									($0.30)	($12.30)	($0.40)
Basic (in dollars per share)									($0.01)	($0.39)	($0.01)

Goodwill_and_Other_Intangible_2

Goodwill and Other Intangible Assets (Goodwill) (Details) (USD $)	12 Months Ended		0 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Nov. 24, 2014	Dec. 31, 2012
Goodwill [Roll Forward]
Balance at end of period	$252.60	$432.70
Magnetic Technologies [Member]
Goodwill [Line Items]
Goodwill test fair value in excess of carrying value				4.00%
Goodwill [Roll Forward]
Balance at beginning of period	214.5	205.2
Divestitures and adjustments		0
Impairment	-168.7
Acquisition	0
Foreign currency translation adjustments	-19.3	9.3
Balance at end of period	26.5	214.5
Advanced Materials [Member]
Goodwill [Roll Forward]
Balance at beginning of period	0	103.3
Divestitures and adjustments		-103.3
Impairment	0
Acquisition	0
Foreign currency translation adjustments	0	0
Balance at end of period	0	0
Specialty Chemicals [Member]
Goodwill [Roll Forward]
Balance at beginning of period	153.1	154.4
Divestitures and adjustments		0
Impairment	0
Acquisition	0
Foreign currency translation adjustments	-6.3	-1.3
Balance at end of period	146.8	153.1
Battery Technologies [Member]
Goodwill [Roll Forward]
Balance at beginning of period	65.1	65.4
Divestitures and adjustments		0
Impairment	0
Acquisition	14.5		14.5
Foreign currency translation adjustments	-0.3	-0.3
Balance at end of period	79.3	65.1
Continuing Operations [Member]
Goodwill [Roll Forward]
Balance at beginning of period	432.7	528.4
Divestitures and adjustments		-103.3
Impairment	-168.7
Acquisition	14.5
Foreign currency translation adjustments	-25.9	7.7
Balance at end of period	252.6	432.7
Discontinued Operations [Member]
Goodwill [Roll Forward]
Balance at beginning of period	0	15
Divestitures and adjustments		-15
Impairment	0
Acquisition	0
Foreign currency translation adjustments	0	0
Balance at end of period	0	0
Consolidated Entities [Member]
Goodwill [Roll Forward]
Balance at beginning of period	432.7	543.4
Divestitures and adjustments		-118.3
Impairment	-168.7
Acquisition	14.5
Foreign currency translation adjustments	-25.9	7.7
Balance at end of period	$252.60	$432.70

Goodwill_and_Other_Intangible_3

Goodwill and Other Intangible Assets (Intangible Assets) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Intangible assets, original value	$513.10		$532.80
Intangible assets, accumulated amortization	-161.6	[1]	-129.8	[1]
Impairment of Intangible Assets, Net	-26.7
Intangible assets, net carrying value	324.8		403
Intangible assets amortization expense	25		26.1		25.5
Future amortization expense [Abstract]
2015	25.2
2016	24.9
2017	24.8
2018	20.7
2019	21.1
UPC Business [Member]
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Non-current intangible assets with a carrying value			17.2
Customer Relationships [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Finite-lived intangible assets, original value	218.2		234.5
Finite-Lived Intangible Assets, Accumulated Amortization	90.1	[1]	82.4	[1]
Impairment of Intangible Assets, Finite-lived	0
Finite-lived intangible assets, net carrying value	128.1		152.1
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Weighted-average useful life of intangible assets (in years)	10 years
Developed Technology [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Finite-lived intangible assets, original value	135.5		136.5
Finite-Lived Intangible Assets, Accumulated Amortization	36.1	[1]	19.9	[1]
Impairment of Intangible Assets, Finite-lived	0
Finite-lived intangible assets, net carrying value	99.4		116.6
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Weighted-average useful life of intangible assets (in years)	12 years
Know-how [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Finite-lived intangible assets, original value	20.1		18.6
Finite-Lived Intangible Assets, Accumulated Amortization	4.6	[1]	3.6	[1]
Impairment of Intangible Assets, Finite-lived	0
Finite-lived intangible assets, net carrying value	15.5		15
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Weighted-average useful life of intangible assets (in years)	16 years
Capitalized Software [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Finite-lived intangible assets, original value	22.3		22
Finite-Lived Intangible Assets, Accumulated Amortization	18.6	[1]	17.4	[1]
Impairment of Intangible Assets, Finite-lived	0
Finite-lived intangible assets, net carrying value	3.7		4.6
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Weighted-average useful life of intangible assets (in years)	3 years
Other Intangible Assets [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Finite-lived intangible assets, original value	2.9		4.2
Finite-Lived Intangible Assets, Accumulated Amortization	2.6	[1]	3.6	[1]
Impairment of Intangible Assets, Finite-lived	0
Finite-lived intangible assets, net carrying value	0.3		0.6
Tradenames [Member]
Indefinite-Lived Intangible Assets (Excluding Goodwill) [Abstract]
Indefinite-Lived Intangible Assets (Excluding Goodwill), Gross	114.1		117
Indefinite-lived Intangible Assets, Accumulated Amortization	9.6	[1]	2.9	[1]
Impairment of Intangible Assets, Finite-lived	-26.7
Indefinite-lived Intangible assets, net carrying value	77.8		114.1
Magnetic Technologies [Member] | Tradenames [Member]
Indefinite-Lived Intangible Assets (Excluding Goodwill) [Abstract]
Impairment of Intangible Assets, Finite-lived	$26.70
[1]	Actual amounts of amortization expense may differ from the estimated amounts due to changes in foreign currency exchange rates, impairment of intangible assets, intangible assets additions, accelerated amortization of intangible assets, acquisitions and divestitures and other factors.

Debt_Details

Debt (Details) (USD $)	12 Months Ended			0 Months Ended		6 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 04, 2013	Sep. 04, 2013	Jun. 30, 2013	Sep. 30, 2014
Line of Credit Facility [Line Items]
Line of credit amount outstanding							$12,500,000
Interest paid on long term debt	0	6,900,000	38,400,000
Interest expense		1,000,000	2,500,000
Interest costs capitalized	0	0	0
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Term of debt instrument				5 years
Undrawn revolving credit facility				350,000,000	350,000,000
Increase limit of borrowing capacity on credit facility				150,000,000	150,000,000
Voting capital stock percentage of certain foreign subsidiaries				65.00%	65.00%
Percentage of pledge of voting capital stock subject to certain exceptions				100.00%
Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member] | Variable Spread [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Percentage of interest rate for base rate loans					1.13%
Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member] | Variable Spread [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Percentage of interest rate for base rate loans					2.00%
Revolving Credit Facility [Member] | Adjusted Base Rate Advances [Member] | Federal Funds Rate [Member]
Line of Credit Facility [Line Items]
Percentage of interest rate for base rate loans					0.50%
Revolving Credit Facility [Member] | Adjusted Base Rate Advances [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Percentage of interest rate for base rate loans					1.00%
Revolving Credit Facility [Member] | Adjusted Base Rate Advances [Member] | Applicable Margin [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Percentage of interest rate for base rate loans					0.13%
Revolving Credit Facility [Member] | Adjusted Base Rate Advances [Member] | Applicable Margin [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Percentage of interest rate for base rate loans					1.00%
Term A Facility [Member]
Line of Credit Facility [Line Items]
Write off of deferred financing fees						10,300,000
Term B Facility [Member]
Line of Credit Facility [Line Items]
Write off of deferred financing fees						$1,500,000

Derivative_Instruments_Narrati

Derivative Instruments (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
		contract	contract
Euro Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Number of derivatives held		0	0
Hedge ineffectiveness recorded to income		$0	$0
Derivative instruments maturity range, months	12 months
Interest Rate Swap Agreements [Member]
Derivatives, Fair Value [Line Items]
Cash flow hedges loss expected to be reclassified to earnings			-100,000
Hedge ineffectiveness recorded to income	0	0	0
Derivative instruments maturity range, months	12 months
Cash Flow Hedging [Member] | Interest Rate Swap Agreements [Member]
Derivatives, Fair Value [Line Items]
Derivative notional amount			$114,500,000

Derivative_Instruments_Effect_

Derivative Instruments (Effect of Derivative Instruments) (Details) (Derivatives Designated As Hedging Instruments [Member], Cash Flow Hedging [Member], USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) on derivative recognized in AOCI(L) (effective portion)	$0	($0.30)	$5.90
Amount of gain (loss) reclassified from AOCI(L) into income (effective portion)	-0.2	-0.2	1.9
Euro Forward Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) on derivative recognized in AOCI(L) (effective portion)	0	0	6
Euro Forward Contracts [Member] | Cost of products sold [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) reclassified from AOCI(L) into income (effective portion)	0	0	2.3
Commodity Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) on derivative recognized in AOCI(L) (effective portion)	0	-0.3	0
Commodity Contracts [Member] | Cost of products sold [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) reclassified from AOCI(L) into income (effective portion)	-0.2	-0.2	0
Interest Rate Swap Agreements [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) on derivative recognized in AOCI(L) (effective portion)	0	0	-0.1
Interest Rate Swap Agreements [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) reclassified from AOCI(L) into income (effective portion)	$0	$0	($0.40)

Fair_Value_Disclosures_Details

Fair Value Disclosures (Details)

12 Months Ended

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2014

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2014

Dec. 31, 2014

Dec. 31, 2014

Dec. 31, 2014

USD ($)

USD ($)

Battery Technologies [Member]

Battery Technologies [Member]

Battery Technologies [Member]

Rahu Catalytics Limited [Member]

Rahu Catalytics Limited [Member]

Rahu Catalytics Limited [Member]

Rahu Catalytics Limited [Member]

Recurring [Member]

Recurring [Member]

Recurring [Member]

Recurring [Member]

customer

customer

customer

USD ($)

EUR (€)

USD ($)

EUR (€)

Contingent Consideration Payable [Member]

Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]

Significant Other Observable Inputs (Level 2) [Member]

Significant Unobservable Inputs (Level 3) [Member]

USD ($)

Contingent Consideration Payable [Member]

Contingent Consideration Payable [Member]

Contingent Consideration Payable [Member]

USD ($)

USD ($)

USD ($)

Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]

Fair value measurements, total liabilities

$1,400,000

$0

$0

$1,400,000

Transfer into or out of fair value measurement

0

0

Initial estimated fair value of contingent consideration based on certain volume targets

24,300,000

20,000,000

Volume targets

15 years

15 years

Revised estimated fair value of contingent consideration based on certain volume targets

1,400,000

1,000,000

Long-term debt, fair value

12,500,000

Long-term debt

$0

$0

Accounts receivable balance from largest customer, percentage

2.00%

2.00%

Number of customers

3

3

3

Entity wide revenue major customer percentage

49.00%

48.00%

52.00%

Fair_Value_Disclosures_Schedul

Fair Value Disclosures - Schedule of changes in Level 3 liabilities measure at fair value on a recurring basis (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	$1.40
Accretion expense	0.2
Foreign exchange	-0.2
Fair value, end of period	$1.40

Income_Taxes_Income_Loss_From_

Income Taxes (Income (Loss) From Continuing Operations Before Income Tax Expense) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income (loss) from continuing operations before income tax expense:
United States	($9)	($13.60)	($12.30)
Outside the United States	-163.8	-49.2	-36.3
Loss from continuing operations before income tax expense	($172.80)	($62.80)	($48.60)

Income_Taxes_Income_Tax_Expens

Income Taxes (Income Tax Expense (Benefit)) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current tax provision (benefit):
Federal	$1.40	$0.60	($3.10)
State and local	0.2	0	0
Outside the United States	15.1	17.4	30.1
Total current	16.7	18	27
Deferred tax provision (benefit):
United States	-1.4	0.6	2.4
Outside the United States	-15.8	-7.9	-32.6
Total deferred	-17.2	-7.3	-30.2
Income tax expense (benefit)	($0.50)	$10.70	($3.20)

Income_Taxes_Effective_Income_

Income Taxes (Effective Income Tax Rates) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Loss from continuing operations before income tax expense	($172.80)	($62.80)	($48.60)
Income taxes at the United States statutory rate (35)%	-60.5	-21.9	-17.1
Increase (decrease) in taxes resulting from:
Effective tax rate differential on income outside of the United States	0	19.3	-3.3
Repatriation of foreign earnings	2.3	-1.7	7.4
Goodwill impairment	52.1	0	0
Valuation allowance	6.7	13.2	3.7
Uncertain tax positions	-1.1	0.1	-1.9
Allowance on GTL prepaid tax asset	0	0.4	5.6
Other, net	0	1.3	2.4
Income tax expense (benefit)	($0.50)	$10.70	($3.20)
Effective income tax rate	27.40%		6.50%
Effective income tax rate at Federal Statutory Income Tax Rate	35.00%	35.00%	35.00%

Income_Taxes_Tax_Expense_Benef

Income Taxes (Tax Expense (Benefit)) (Details) (USD $)	12 Months Ended			3 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Mar. 29, 2013
Schedule of Tax Expense (Benefit) [Line Items]
Goodwill and intangible asset impairment	$195,400,000	$0	$0
Cost reductions initiatives	10,000,000
Effective income tax rate	27.40%		6.50%
Loss on divestiture of advance materials business	-1,700,000	111,600,000	0
Percentage of interest in joint venture by the company										55.00%
Income tax receivable, current			37,900,000
Undistributed earnings of consolidated foreign subsidiaries with no U.S. income tax provision	402,000,000			402,000,000
Income Taxes Paid	18,800,000	47,200,000	33,900,000
Parent [Member]
Schedule of Tax Expense (Benefit) [Line Items]
Discrete tax benefit related to the GTL joint venture			6,700,000
VAC [Member]
Schedule of Tax Expense (Benefit) [Line Items]
Charges as a result of step-up of inventory to fair value			55,900,000
GTL [Member]
Schedule of Tax Expense (Benefit) [Line Items]
Effective income tax rate, excluding discrete items			31.80%
Discrete tax expense related to the GTL joint venture			10,400,000
Discrete tax expense related to GTL, prepaid tax asset impairment			5,600,000
Discrete tax expense related to joint venture, permanent differences			6,600,000
Percentage of interest in joint venture by the company			55.00%
Magnetic Technologies [Member]
Schedule of Tax Expense (Benefit) [Line Items]
Cost reductions initiatives	1,900,000	5,400,000		1,600,000	300,000	400,000	700,000	400,000	3,800,000
Goodwill impairment loss	168,700,000
Advanced Materials [Member]
Schedule of Tax Expense (Benefit) [Line Items]
Goodwill impairment loss	0
Loss on divestiture of advance materials business		$111,600,000							$111,600,000
Effective income tax rate, excluding discrete items		22.10%

Income_Taxes_Net_Deferred_Tax_

Income Taxes (Net Deferred Tax Liabilities) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Components of deferred tax assets and liabilities
Employee benefit accruals	$58.60	$44.70
Foreign operating loss carryforwards	6.5	8.3
Foreign tax credit carryforwards	17.3	23.1
State operating loss carryforwards	7.8	7.6
Operating accruals	48.4	42.3
Investment credit carryforwards	2.6	3.3
Valuation allowance	-91.9	-83.6
Deferred tax assets	49.3	45.7
Depreciation	-31.2	-37.5
Amortization	-88.5	-107.7
Other	-0.2	-1
Deferred tax liabilities	-119.9	-146.2
Net deferred tax liabilities	-70.6	-100.5
Deferred tax assets and liabilities
Other current assets	2.1	2.4
Other non-current assets	5.3	6.4
Other current liabilities	-3.2	-6.8
Deferred income taxes — non-current liabilities	-74.8	-102.5
Net deferred tax liabilities	($70.60)	($100.50)

Income_Taxes_Tax_Carryforwards

Income Taxes (Tax Carryforwards) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Operating Loss, Tax Credit and Other Tax Carryforwards [Line Items]
Foreign net operating loss carryforwards potential future tax benefit	$6.50	$8.30
U.S. [Member]
Operating Loss, Tax Credit and Other Tax Carryforwards [Line Items]
U.S. net deferred tax asset expected to be recovered based on temporary differences that will reverse in 2014-2015	1.4
U.S. State [Member]
Operating Loss, Tax Credit and Other Tax Carryforwards [Line Items]
Net operating loss carryforwards potential future tax benefit	7.8	7.7
Foreign [Member]
Operating Loss, Tax Credit and Other Tax Carryforwards [Line Items]
Net operating loss carryforwards	30.6
Foreign net operating loss carryforwards potential future tax benefit	6.5
Net operating loss carryforwards valuation allowance	1.8
Foreign [Member] | Investment Tax Credit [Member]
Operating Loss, Tax Credit and Other Tax Carryforwards [Line Items]
Tax credit carryforward	2.6
Tax credit carryforward, expire in 2028	1.9
Tax credit carryforward, no expiration	0.7
Tax credit carryforward valuation allowance	$1.90

Income_Taxes_Uncertain_Tax_Pos

Income Taxes (Uncertain Tax Positions) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of uncertain tax positions [Roll Forward]
Balance at beginning of the period	$15.50	$18
Additions for tax positions related to the current year	0.4	0.6
Addition of receivable for prior year tax position	-0.7
Reductions for tax positions of prior years	-0.6	-3.4
Reductions for lapses of statute of limitations	-0.1
Foreign currency translation		0.3
Balance at end of the period	13.7	15.5
Liability for uncertain tax positions reasonably possible will decrease within the next 12 months	5.9
Unrecognized tax benefits, interest and penalties accrued	0.6	0.8
Unrecognized Tax Benefits, Decrease Resulting from Foreign Currency Translation	-0.8
Foreign [Member]
Reconciliation of uncertain tax positions [Roll Forward]
Unrecognized tax benefits that would be offset by adjustment to valuation allowance	$6.10

Pension_and_Other_PostRetireme2

Pension and Other Post-Retirement Benefit Plans (Narrative) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Aggregate defined contribution plan expenses	$3.30	$4.70	$4.90
U.S. Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Settlements plan assets	29.6	0
Settlement charge	-3.2	0	0
Expected employer contribution in 2014	0.7
EPT Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of U.S. plan assets	93.00%
Non-U.S. Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Settlements plan assets	0	0
Expected employer contribution in 2014	10.7
Battery Technologies [Member]
Defined Benefit Plan Disclosure [Line Items]
Settlement charge	$3.20
EaglePicher Technologies [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of benefit plans assumed in acquisition	4
Number of frozen defined benefit pension plans with liabilities company assumed in acquisition	2

Pension_and_Other_PostRetireme3

Pension and Other Post-Retirement Benefit Plans (Schedule of Changes in Benefit Obligation and Plan Assets, Funded Status and Amounts Recognized in Consolidated Balance Sheets) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
U.S. Pension Plans [Member]
Change in benefit obligation [Roll Forward]
Projected benefit obligation at beginning of year	($220.50)	($245)
Service cost	-1	-1.2	-1.1
Interest cost	-9.2	-8.4	-9.3
Actuarial (loss) gain	-29.4	20.2
Benefits paid	14.4	13.9
Settlement	29.6	0
Foreign currency exchange rate changes	0	0
Projected benefit obligation at end of year	-216.1	-220.5	-245
Change in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	177.4	180.5
Actual return on plan assets	17.2	5.7
Employer contributions	1.5	5.1
Settlement	-29.6	0
Foreign currency exchange rate changes	0	0
Benefits paid	-14.4	-13.9
Fair value of plan assets at end of year	152.1	177.4	180.5
Funded status — plan assets less than benefit obligations	-64	-43.1
Recognized in accumulated other comprehensive income:
Net actuarial loss (gain)	18.4	-16.9
Amounts not yet recognized as a component of net postretirement benefit cost	36.3	17.9
Amounts recorded in the balance sheet:
Accrued benefit liability — current	-0.6	-0.7
Accrued benefit liability — long-term	-63.4	-42.4
Amounts not yet recognized as a component of net postretirement benefit cost	36.3	17.9
Net amount recognized	-27.7	-25.2
Accumulated benefit obligation at end of year	215.6	220.1
Non-U.S. Pension Plans [Member]
Change in benefit obligation [Roll Forward]
Projected benefit obligation at beginning of year	-191.1	-181.4
Service cost	-6.8	-5.1	-4
Interest cost	-6.1	-6.1	-7.6
Actuarial (loss) gain	-25.8	-0.4
Benefits paid	10.3	10.2
Settlement	0	0
Foreign currency exchange rate changes	25.3	-8.3
Projected benefit obligation at end of year	-194.2	-191.1	-181.4
Change in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	4.2	4
Actual return on plan assets	0	0
Employer contributions	11.9	10.1
Settlement	0	0
Foreign currency exchange rate changes	-0.7	0.3
Benefits paid	-10.3	-10.2
Fair value of plan assets at end of year	5.1	4.2	4
Funded status — plan assets less than benefit obligations	-189.1	-186.9
Recognized in accumulated other comprehensive income:
Net actuarial loss (gain)	18.4	-0.1
Amounts not yet recognized as a component of net postretirement benefit cost	49.6	31.2
Amounts recorded in the balance sheet:
Accrued benefit liability — current	-8.1	-8.8
Accrued benefit liability — long-term	-181	-178.1
Amounts not yet recognized as a component of net postretirement benefit cost	49.6	31.2
Net amount recognized	-139.5	-155.7
Accumulated benefit obligation at end of year	$182.70	$189.80

Pension_and_Other_PostRetireme4

Pension and Other Post-Retirement Benefit Plans (Schedule of Net Benefit Costs and Amounts Recognized in Other Comprehensive Income (Loss)) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
U.S. Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$1	$1.20	$1.10
Interest cost	9.2	8.4	9.3
Amortization of unrecognized net loss	1.4	0.3	1.5
Expected return on plan assets	-10.7	-9.4	-10.4
Settlement charge	3.2	0	0
Net periodic benefit cost	4.1	0.5	1.5
Net loss (gain) arising during the year	22.1	-16.1	1.3
Net gain recognized during the year	-3.6	-0.8	-3.4
Total recognized in other comprehensive loss	18.5	-16.9	-2.1
Total recognized in net periodic benefit cost and other comprehensive loss	22.6	-16.4	-0.6
Non-U.S. Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	6.8	5.1	4
Interest cost	6.1	6.1	7.6
Amortization of unrecognized net loss	1.6	1.8	0.8
Net periodic benefit cost	14.5	13	12.4
Net loss (gain) arising during the year	25.8	0.3	29.8
Net gain recognized during the year	1.6	1.8	0.8
Exchange rate gain (loss) gain	-5.8	1.4	0.8
Total recognized in other comprehensive loss	18.4	-0.1	29.8
Total recognized in net periodic benefit cost and other comprehensive loss	32.9	12.9	42.2
Battery Technologies [Member]
Defined Benefit Plan Disclosure [Line Items]
Settlement charge	($3.20)

Pension_and_Other_PostRetireme5

Pension and Other Post-Retirement Benefit Plans (Future Expected Pension Benefit Payments) (Details) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified
U.S. Pension Plans [Member]
Future pension benefit payments expected to be paid:
2015	$14.40
2016	14.1
2017	14
2018	13.9
2019	13.8
2020 - 2024	67.6
Non-U.S. Pension Plans [Member]
Future pension benefit payments expected to be paid:
2015	10.7
2016	12.1
2017	12.3
2018	12
2019	10.4
2020 - 2024	$51.40

Pension_and_Other_PostRetireme6

Pension and Other Post-Retirement Benefit Plans (Schedule of Amounts in Accumulated Other Comprehensive Income (Loss) Expected to be Recognized during 2012) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014
Pension Plans [Member]
Amounts in Accumulated other comprehensive income (loss) that are expected to be recognized during 2012:
Net actuarial loss	$3.50
U.S. Pension Plans [Member]
Amounts in Accumulated other comprehensive income (loss) that are expected to be recognized during 2012:
Net actuarial loss	0.9
Non-U.S. Pension Plans [Member]
Amounts in Accumulated other comprehensive income (loss) that are expected to be recognized during 2012:
Net actuarial loss	$2.60

Pension_and_Other_PostRetireme7

Pension and Other Post-Retirement Benefit Plans (Schedule of Weighted-Average Assumptions Used) (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
U.S. Pension Plans [Member]
Weighted-average assumptions were used to determine benefit obligations:
Rate of increases in compensation	3.50%	3.50%
EPT Pension Plans [Member] | Active Plans [Member]
Weighted-average assumptions were used to determine benefit obligations:
Discount rate	3.70%	4.60%
Expected return on pension plan assets	6.30%	6.50%
Weighted-average assumptions were used to determine net periodic benefit costs:
Discount rate	4.60%	3.70%
Expected return on pension plan assets	6.50%	7.00%
EPT Pension Plans [Member] | Inactive Plans [Member]
Weighted-average assumptions were used to determine benefit obligations:
Discount rate	3.50%	4.40%
Expected return on pension plan assets	6.30%	6.50%
Weighted-average assumptions were used to determine net periodic benefit costs:
Discount rate	4.40%	3.50%
Expected return on pension plan assets	6.50%	4.70%
Divested Business Plans [Member]
Weighted-average assumptions were used to determine benefit obligations:
Discount rate	3.50%	4.30%
Expected return on pension plan assets	6.30%	6.50%
Weighted-average assumptions were used to determine net periodic benefit costs:
Discount rate	4.30%	3.40%
Expected return on pension plan assets	6.50%	6.00%
Non-U.S. Pension Plans [Member]
Weighted-average assumptions were used to determine benefit obligations:
Discount rate	2.00%	3.50%
Weighted-average assumptions were used to determine net periodic benefit costs:
Discount rate	3.50%	3.50%
Expected return on pension plan assets	3.50%	3.70%
Non-U.S. Pension Plans [Member] | Minimum [Member]
Weighted-average assumptions were used to determine benefit obligations:
Rate of increases in compensation	2.50%	3.00%
Non-U.S. Pension Plans [Member] | Maximum [Member]
Weighted-average assumptions were used to determine benefit obligations:
Rate of increases in compensation	2.50%	3.00%

Pension_and_Other_PostRetireme8

Pension and Other Post-Retirement Benefit Plans (Schedule of Plan Assets Allocations) (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
EPT Pension Plans [Member] | Active Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual allocation percentage	100.00%
Target allocation percentage	100.00%
EPT Pension Plans [Member] | Active Plans [Member] | U.S. Equity Securites [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual allocation percentage	11.00%
Target allocation percentage	11.00%
EPT Pension Plans [Member] | Active Plans [Member] | Non-US Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual allocation percentage	11.00%
Target allocation percentage	11.00%
EPT Pension Plans [Member] | Active Plans [Member] | Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual allocation percentage	62.00%
Target allocation percentage	62.00%
EPT Pension Plans [Member] | Active Plans [Member] | High Yield [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual allocation percentage	5.00%
Target allocation percentage	5.00%
EPT Pension Plans [Member] | Active Plans [Member] | TIPS [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual allocation percentage	5.00%
Target allocation percentage	5.00%
EPT Pension Plans [Member] | Active Plans [Member] | Global REITS [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual allocation percentage	5.00%
Target allocation percentage	5.00%
EPT Pension Plans [Member] | Active Plans [Member] | Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual allocation percentage	1.00%
Target allocation percentage	1.00%
SCM and Non-U.S. Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual allocation percentage	100.00%	100.00%
SCM and Non-U.S. Pension Plans [Member] | U.S. Equity Securites [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual allocation percentage	33.00%	38.00%
SCM and Non-U.S. Pension Plans [Member] | Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual allocation percentage	8.00%	10.00%
SCM and Non-U.S. Pension Plans [Member] | Government Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual allocation percentage	11.00%	10.00%
SCM and Non-U.S. Pension Plans [Member] | Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual allocation percentage	15.00%	13.00%
SCM and Non-U.S. Pension Plans [Member] | Non-US Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual allocation percentage	31.00%	27.00%
SCM and Non-U.S. Pension Plans [Member] | Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual allocation percentage	2.00%	2.00%

Pension_and_Other_PostRetireme9

Pension and Other Post-Retirement Benefit Plans (Schedule of Fair Value of Plan Assets) (Details) (Pension Plans [Member], USD $)	Dec. 31, 2014
In Millions, unless otherwise specified
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	$157.20
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	5.6
Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	151.6
Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	0
Equity Securities - US [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	21.2
Equity Securities - US [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	3.9
Equity Securities - US [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	17.3
Equity Securities - US [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	0
Non-US Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	15.4
Non-US Equity Securities [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	0
Non-US Equity Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	15.4
Non-US Equity Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	0
Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	88.6
Bonds [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	0
Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	88.6
Bonds [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	0
Other Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	4.3
Other Fixed Income [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	0
Other Fixed Income [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	4.3
Other Fixed Income [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	0
High Yield [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	7.2
High Yield [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	0
High Yield [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	7.2
High Yield [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	0
TIPS [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	6.7
TIPS [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	0
TIPS [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	6.7
TIPS [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	0
Global REITS [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	7
Global REITS [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	0
Global REITS [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	7
Global REITS [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	0
Non-US Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	5.1
Non-US Assets [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	0
Non-US Assets [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	5.1
Non-US Assets [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	0
Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	1.7
Cash and Cash Equivalents [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	1.7
Cash and Cash Equivalents [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	0
Cash and Cash Equivalents [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	$0

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income (Loss) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	($45.20)
Other comprehensive (loss) income before reclassifications	-118
Amounts reclassified from accumulated other comprehensive income (loss)	5.4
Net change in accumulated other comprehensive income (loss)	-112.6	42.8	5.4
Balance at end of period	-157.8	-45.2
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	-5.5
Other comprehensive (loss) income before reclassifications	-81.7
Amounts reclassified from accumulated other comprehensive income (loss)	0
Net change in accumulated other comprehensive income (loss)	-81.7
Balance at end of period	-87.2
Unrealized Gains and Losses on Cash Flow Hedging Derivatives [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	-0.2
Other comprehensive (loss) income before reclassifications	0
Amounts reclassified from accumulated other comprehensive income (loss)	0.2
Net change in accumulated other comprehensive income (loss)	0.2
Balance at end of period	0
Unrealized Gains and Losses on Cash Flow Hedging Derivatives [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Cost of goods sold	0.2
Pension and Post-Retirement Obligation [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	-49.1
Other comprehensive (loss) income before reclassifications	-42
Amounts reclassified from accumulated other comprehensive income (loss)	5.2
Net change in accumulated other comprehensive income (loss)	-36.8
Balance at end of period	-85.9
Deferred Tax Asset [Domain]
Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	9.6
Other comprehensive (loss) income before reclassifications	5.7
Amounts reclassified from accumulated other comprehensive income (loss)	0
Net change in accumulated other comprehensive income (loss)	5.7
Balance at end of period	$15.30

Earnings_Per_Share_Computation

Earnings Per Share (Computation of Basic And Diluted Income Per Common Share From Continuing Operations) (Details) (USD $)	3 Months Ended								12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Earnings Per Share [Abstract]
Loss from continuing operations, net of tax	($189)	$6.30	$5.10	$5.30	$17.30	$12.40	$8.10	($109.50)	($172.30)	($71.70)	($38.30)
Earnings per common share:
Loss from continuing operations	($6.24)	$0.20	$0.16	$0.17	$0.54	$0.40	$0.26	($3.47)	($5.54)	($2.27)	($1.21)
Loss from continuing operations	($6.24)	$0.20	$0.16	$0.16	$0.54	$0.39	$0.26	($3.46)	($5.54)	($2.27)	($1.21)
Weighted average shares outstanding — basic (in shares)									31.1	31.6	31.9
Dilutive effect of stock options and restricted stock (in shares)									0	0	0
Weighted average shares outstanding — assuming dilution (in shares)									31.1	31.6	31.9

Earnings_Per_Share_Computation1

Earnings Per Share (Computation of Basic And Diluted Net Income Per Common Share) (Details) (USD $)	3 Months Ended								12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Earnings Per Share [Abstract]
Net loss	($189)	$6.40	$4.80	$5.20	$17.20	$12.10	($3.30)	($110)	($172.60)	($84)	($38.70)
Earnings per common share:
Net loss attributable to OM Group, Inc. common stockholders - basic (in dollars per share)	($6.24)	$0.21	$0.15	$0.17	$0.54	$0.39	($0.10)	($3.49)	($5.55)	($2.66)	($1.22)
Net loss attributable to OM Group, Inc. common stockholders - assuming dilution (in dollars per share)	($6.24)	$0.20	$0.15	$0.16	$0.54	$0.38	($0.10)	($3.48)	($5.55)	($2.66)	($1.22)
Weighted average shares outstanding — basic (in shares)									31.1	31.6	31.9
Dilutive effect of stock options and restricted stock (in shares)									0	0	0
Weighted average shares outstanding — assuming dilution (in shares)									31.1	31.6	31.9

Earnings_Per_Share_NonVested_S

Earnings Per Share (Non-Vested Share-Based Compensation Awards That Could Potentially Dilute Earnings Per Share) (Details)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share [Abstract]
Non-vested share-based compensation awards not included in the fully diluted computation	0.1	0.1

ShareBased_Compensation_Narrat

Share-Based Compensation (Narrative) (Details) (USD $)	12 Months Ended			6 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	2,550,000
Share-based compensation arrangement by share-based payment award, number of shares per award	$1.79
Tax benefit recognized as a result of the valuation allowance	$0	$0	$0
Unrecognized compensation expense	6,300,000
Unrecognized compensation expense, expected to be recognized in 2015	4,600,000
Unrecognized compensation expense, expected to be recognized in 2016	1,600,000
Unrecognized compensation expense, expected to be recognized in 2017	100,000
Number of shares issued to non-employee directors	8,795
Dividend yield assumption	0.94%	0.00%	0.00%
Proceeds from exercise of stock options	500,000	2,800,000	0
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Number of Shares Per Employee	400,000
Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares issued to non-employee directors		18,069	23,752	7,084
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Percentage of stock options vested and exercisable upon change of control	100.00%
Minimum vesting period to consider stock options as one award	1 year
Stock options granted	230,300	273,200	238,319
Dividend yield assumption	0.94%
Fair value of options vested	3,300,000	3,700,000	3,500,000
Intrinsic value of options exercised	100,000	1,200,000
Exercised	-18,764		0
Proceeds from exercise of stock options	500,000	2,800,000
Stock Options [Member] | Chief Executive Officer [Member] | One Year Vesting [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year
Stock options granted			4,419
Performance-Based Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Target percentage of initial grant	50.00%
Period for measuring performance criteria	3 years
Shares meeting performance objectives	4.00%
Performance-Based Awards [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Target percentage of initial grant	0.00%
Performance-Based Awards [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Target percentage of initial grant	100.00%
Restricted Stock - Performance-Based Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity Instruments other than options, granted	206,225	245,950	130,500
Granted and expected to vest	57,189
Restricted Stock - Performance-Based Awards [Member] | Two Thousand Twelve [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted and expected to vest	548
Restricted Stock - Performance-Based Awards [Member] | Two Thousand Ten [Member] | Three Year Vesting [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted and expected to vest	850
RSUs - Performance-Based Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	1,424,581
Equity Instruments other than options, granted	24,175	35,150	33,450
Granted and expected to vest	9,516
RSUs - Performance-Based Awards [Member] | Two Thousand Twelve [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted and expected to vest	3,927
RSUs - Performance-Based Awards [Member] | Two Thousand Ten [Member] | Three Year Vesting [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted and expected to vest	18,194
Time-Based Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Value of shares issued under plan	$600,000	$1,500,000	$2,600,000
Restricted Stock Units - Time-Based Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
U.S. RSUs - Time-Based Awards [Member] | Three Year Vesting [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity Instruments other than options, granted	18,525	60,000	69,327
International RSUs - Time-Based Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity Instruments other than options, granted	6,050	7,950	17,060
Granted and expected to vest	13,967
Restricted Stock - Time-Based Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of performance-based restricted stock awards vested upon change of control units	100.00%
U.S. Restricted Stock - Time-Based Awards [Member] | Three Year Vesting [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity Instruments other than options, granted			20,000
U.S. Restricted Stock - Time-Based Awards [Member] | Chief Executive Officer [Member] | One Year Vesting [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity Instruments other than options, granted			2,177

ShareBased_Compensation_Summar

Share-Based Compensation (Summary of Share-Based Compensation Expense) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$7.10	$5.70	$5.20
Employees [Member] | Stock Options and Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	6.5	5.4	5
Employees [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	0.6	0.3	0.2
Non-Employee Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$0.50	$0.50	$0.50

ShareBased_Compensation_Stock_

Share-Based Compensation (Stock Options Valuation Assumptions) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation [Abstract]
Risk-free interest rate	1.90%	1.10%	1.10%
Dividend yield	0.94%	0.00%	0.00%
Volatility factor of Company common stock	56.00%	54.00%	55.00%
Weighted-average expected option term	6 years	6 years	6 years
Weighted-average grant-date fair value	$15.03	$13.49	$15.29

ShareBased_Compensation_Number

Share-Based Compensation (Number of Shares And Weighted-Average Grant-Date Fair Value) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Weighted-Average Fair Value at Grant Date (in dollars per share) [Roll Forward]
Granted	$15.03	$13.49	$15.29
Stock Options [Member]
Shares [Roll Forward]
Non-vested at beginning balance	436,027	442,626
Granted	230,300	273,200	238,319
Vested	-218,532	-214,816
Forfeited	-26,581	-64,983
Non-vested at ending balance	421,214	436,027	442,626
Weighted-Average Fair Value at Grant Date (in dollars per share) [Roll Forward]
Non-vested beginning balance	$14.78	$17.20
Granted	$15.03	$13.49
Vested	$15.18	$17.37
Forfeited	$14.74	$16.02
Non-vested ending balance	$14.36	$14.78	$17.20

ShareBased_Compensation_Summar1

Share-Based Compensation (Summary of Stock Option Activity) (Details) (Stock Options [Member], USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stock Options [Member]
Shares [Roll Forward]
Outstanding, beginning balance	1,308,573
Granted	230,300	273,200	238,319
Exercised	-18,764		0
Expired unexercised	-36,201
Forfeited	-26,581
Outstanding, ending balance	1,457,327	1,308,573
Vested or expected to vest, ending balance	1,431,451
Exercisable, ending balance	1,042,314
Weighted Average Exercise Price (in dollars per share) [Roll Forward]
Outstanding, beginning balance	$34.81
Granted	$32.06
Exercised	$28.03
Expired unexercised	$38.91
Forfeited	$29.96
Outstanding, ending balance	$32.97	$34.81
Vested or expected to vest, ending balance	$33.04
Exercisable, ending balance	$34.30
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contractual term (years), outstanding, ending balance	5 years 5 months 9 days
Weighted average remaining contractual term (years), vested or Expected to Vest, ending balance	5 years 4 months 21 days
Weighted average remaining contractual term (years), exercisable, ending balance	4 years 2 months 16 days
Aggregate intrinsic value, outstanding, ending balance	$7.90
Aggregate intrinsic value, vested or expected to vest, ending balance	7.7
Aggregate intrinsic value, exercisable, ending balance	$4.40

ShareBased_Compensation_Summar2

Share-Based Compensation (Summary of Performance-Based and Time-Based Restricted Awards) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
RSUs - Performance-Based Awards [Member]
Shares:
Non-vested, beginning balance	61,250
Granted	24,175	35,150	33,450
Vested	-850
Forfeited	-12,183
Non-vested, ending balance	72,392	61,250
Expected to vest, ending balance	9,516
Restricted Stock - Performance-Based Awards [Member]
Shares:
Non-vested, beginning balance	435,090
Granted	206,225	245,950	130,500
Vested	-18,194
Forfeited	-125,617
Non-vested, ending balance	497,504	435,090
Expected to vest, ending balance	57,189
Performance-Based Awards [Member]
Weighted Average Grant Date Fair Value (in dollars per share):
Non-vested, beginning balance	29.56
Granted	32.2
Vested	36.51
Forfeited	33.63
Non-vested, ending balance	29.37
International RSUs - Time-Based Awards [Member]
Shares:
Non-vested, beginning balance	16,330
Granted	6,050	7,950	17,060
Vested	-6,220
Forfeited	-1,085
Non-vested, ending balance	15,075	16,330
Expected to vest, ending balance	13,967
International RSUs - Time-Based Awards [Member] | Three Year Vesting [Member]
Shares:
Granted	6,050
US Time-Based Awards [Member]
Shares:
Non-vested, beginning balance	180,560
Vested	-50,895
Forfeited	-13,020
Non-vested, ending balance	135,170
Expected to vest, ending balance	130,174
Weighted Average Grant Date Fair Value (in dollars per share):
Non-vested, beginning balance	29.26
Vested	35.99
Forfeited	29.63
Non-vested, ending balance	27.08
US Time-Based Awards [Member] | Three Year Vesting [Member]
Shares:
Granted	18,525
Vested	-50,895	-54,300	-22,100
Weighted Average Grant Date Fair Value (in dollars per share):
Granted	32.17

ShareBased_Compensation_Schedu

Share-Based Compensation (Schedule of Performance-Based and Time-Based Shares Vested and Issued) (Details) (US Time-Based Awards [Member])	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested based on meeting performance criteria	50,895
Shares surrendered to pay withholding taxes	-18,069	-19,645	-8,538
Net shares issued	32,826	36,832	16,329
Three Year Vesting [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested based on meeting performance criteria	50,895	54,300	22,100
One Year Vesting [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested based on meeting performance criteria	0	2,177	2,767

Lease_Obligations_Details

Lease Obligations (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Leases, Operating [Abstract]
Operating lease expense	$8	$8.80	$9.60
Future minimum payments under noncancellable operating leases:
2015	6.6
2016	6
2017	5.1
2018	3.4
2019	2.1
Thereafter	8.2
Total minimum lease payments	$31.40

Reportable_Segments_and_Geogra2

Reportable Segments and Geographic Information (Reportable Segments) (Details) (USD $)	3 Months Ended										12 Months Ended
	Dec. 31, 2014		Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013		Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
											segment
Segment Reporting Information [Line Items]
Number of operating segments											4
Net sales
Net sales	$245,400,000		$262,900,000	$297,500,000	$261,700,000	$270,500,000		$265,700,000	$279,500,000	$341,800,000	$1,067,500,000	[1],[2]	$1,157,500,000	[1],[2]	$1,544,400,000	[1],[2]
Operating profit (loss)
Operating profit (loss)											-165,100,000		41,100,000		-4,700,000
Interest expense											-2,600,000		-12,300,000		-49,700,000
Foreign exchange gain (loss)											-6,500,000		8,000,000		-800,000
Gain (loss) on divestiture of Advance Materials business											1,700,000		-111,600,000		0
Other income (expense), net											-300,000		12,000,000		6,600,000
Non operating income (expense), total											-7,700,000		-103,900,000		-43,900,000
Loss from continuing operations before income tax expense											-172,800,000		-62,800,000		-48,600,000
Expenditures for property, plant & equipment
Expenditures for property, plant & equipment											34,500,000		53,100,000		67,600,000
Depreciation and amortization
Depreciation and amortization											67,500,000		73,900,000		84,300,000
Total assets
Total assets	1,419,500,000					1,783,100,000					1,419,500,000		1,783,100,000
Asset impairment charges											195,400,000		0		0
Cost reductions initiatives											10,000,000
Gain on sale of property											0		0		2,900,000
U.S. Pension Plans [Member]
Total assets
Settlement charge											-3,200,000		0		0
Magnetic Technologies [Member]
Net sales
Net sales											495,000,000		522,600,000		631,600,000
Operating profit (loss)
Operating profit (loss)											-177,100,000	[3],[4],[5]	22,400,000	[3],[4],[5]	-22,300,000	[3],[4],[5]
Expenditures for property, plant & equipment
Expenditures for property, plant & equipment											26,500,000		30,800,000		27,300,000
Depreciation and amortization
Depreciation and amortization											42,200,000		44,200,000		40,800,000
Total assets
Total assets	675,000,000					1,020,600,000					675,000,000		1,020,600,000
Asset impairment charges											195,400,000
Cost reductions initiatives	1,600,000		300,000			400,000		700,000	400,000	3,800,000	1,900,000		5,400,000
Amount of inventory step-up amortization															55,900,000
Specialty Chemicals [Member]
Net sales
Net sales											316,100,000	[6]	318,600,000	[6]	323,600,000	[6]
Operating profit (loss)
Operating profit (loss)											31,300,000	[3],[4],[6],[7]	35,800,000	[3],[4],[6],[7]	34,500,000	[3],[4],[6],[7]
Expenditures for property, plant & equipment
Expenditures for property, plant & equipment											3,100,000	[6]	7,600,000	[6]	4,900,000	[6]
Depreciation and amortization
Depreciation and amortization											14,000,000	[6]	14,800,000	[6]	15,700,000	[6]
Total assets
Total assets	396,300,000	[6]				416,500,000	[6]				396,300,000	[6]	416,500,000	[6]
Cost reductions initiatives	700,000		1,000,000	400,000					1,100,000		2,100,000		1,100,000
Battery Technologies [Member]
Net sales
Net sales											153,800,000		150,300,000		143,000,000
Operating profit (loss)
Operating profit (loss)											19,900,000	[3],[4]	21,800,000	[3],[4]	19,600,000	[3],[4]
Expenditures for property, plant & equipment
Expenditures for property, plant & equipment											4,500,000		5,300,000		5,800,000
Depreciation and amortization
Depreciation and amortization											10,500,000		10,100,000		10,100,000
Total assets
Total assets	265,900,000					237,400,000					265,900,000		237,400,000
Cost reductions initiatives			2,600,000						500,000	200,000	2,600,000		800,000
Settlement charge											3,200,000
Advanced Materials [Member]
Net sales
Net sales											102,600,000		166,300,000		447,000,000
Operating profit (loss)
Operating profit (loss)											-5,600,000		-400,000		6,400,000
Gain (loss) on divestiture of Advance Materials business										-111,600,000			-111,600,000
Expenditures for property, plant & equipment
Expenditures for property, plant & equipment											0		6,300,000		29,600,000
Depreciation and amortization
Depreciation and amortization											0		3,900,000		16,900,000
Total assets
Total assets	10,600,000					17,900,000					10,600,000		17,900,000
Intersegment Items [Member]
Net sales
Net sales											0		-300,000		-800,000
Corporate [Member]
Operating profit (loss)
Operating profit (loss)											-33,600,000	[3],[4],[8]	-38,500,000	[3],[4],[8]	-42,900,000	[3],[4],[8]
Expenditures for property, plant & equipment
Expenditures for property, plant & equipment											400,000		3,100,000		0
Depreciation and amortization
Depreciation and amortization											800,000		900,000		800,000
Total assets
Total assets	71,700,000					90,700,000					71,700,000		90,700,000
Cost reductions initiatives	100,000		100,000			1,400,000		1,000,000			200,000		2,400,000
Corporate [Member] | U.S. Pension Plans [Member]
Total assets
Settlement charge															$2,500,000
[1]	Net sales attributed to the geographic area are based on the location of the manufacturing facility, except for Japan, which was a sales office and included in the divestiture of the Advance Materials business.
[2]	All results and balances related to the UPC business are excluded for all periods presented.
[3]	The year ended December 31, 2014 includes a $195.4 million goodwill and intangible asset non-cash impairment charge in Magnetic Technologies. The results also include costs related to cost optimization and other business improvement initiatives of $1.9 million in Magnetic Technologies, $2.6 million in Battery Technologies, $2.1 million in Specialty Chemicals, and $0.2 million in Corporate, respectively. Cost reduction initiatives include headcount reductions, minor facility consolidation, supply chain optimization, corporate cost reductions, and other structural changes. There was also a $3.2 million non-cash pension settlement charge in Battery Technologies during the fourth quarter.
[4]	The year ended December 31, 2013 includes charges related to cost reduction initiatives of $5.4 million in Magnetic Technologies, $0.8 million in Battery Technologies, $1.1 million in Specialty Chemicals and $2.4 million in Corporate, respectively
[5]	Includes $55.9 million of charges related to the VAC inventory purchase accounting step-up and LCM charges in 2012.
[6]	All results related to the UPC business are excluded from the Specialty Chemicals segment for all periods presented.
[7]	Includes property sale gains of $2.9 million in 2012.
[8]	Includes a $2.5 million non-cash pension settlement charge to certain participants in one of our U.S. defined benefit pension plans in 2012. Net Sales(a)(c) Long-LivedAssets(b)(c)Geographic Region Information 2014 Germany 544.3 217.5United States 263.3 76.1Finland 102.6 —Other 157.3 14.7 $1,067.5 $308.32013 Germany $571.9 $247.9United States 296.2 79.5Finland 102.6 —Japan 29.3 —Other 157.5 18.2 $1,157.5 $345.62012 Germany $681.4 United States 324.9 Finland 229.7 Japan 161.7 Other 146.7 $1,544.4

Reportable_Segments_and_Geogra3

Reportable Segments and Geographic Information (Schedule of Geographic Information) (Details) (USD $)

3 Months Ended

12 Months Ended

In Millions, unless otherwise specified

Dec. 31, 2014

Sep. 30, 2014

Jun. 30, 2014

Mar. 31, 2014

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Segment Reporting Information [Line Items]

Net sales

$245.40

$262.90

$297.50

$261.70

$270.50

$265.70

$279.50

$341.80

$1,067.50

[1],[2]

$1,157.50

[1],[2]

$1,544.40

[1],[2]

Long-lived assets

308.3

[2],[3]

345.6

[2],[3]

308.3

[2],[3]

345.6

[2],[3]

[2],[3]

Germany [Member]

Segment Reporting Information [Line Items]

Net sales

544.3

[1],[2]

571.9

[1],[2]

681.4

[1],[2]

Long-lived assets

217.5

[2],[3]

247.9

[2],[3]

217.5

[2],[3]

247.9

[2],[3]

United States [Member]

Segment Reporting Information [Line Items]

Net sales

263.3

[1],[2]

296.2

[1],[2]

324.9

[1],[2]

Long-lived assets

76.1

[2],[3]

79.5

[2],[3]

76.1

[2],[3]

79.5

[2],[3]

Finland [Member]

Segment Reporting Information [Line Items]

Net sales

102.6

[1],[2]

102.6

[1],[2]

229.7

[1],[2]

Long-lived assets

0

[2],[3]

0

[2],[3]

0

[2],[3]

0

[2],[3]

Japan [Member]

Segment Reporting Information [Line Items]

Net sales

29.3

[1],[2]

161.7

[1],[2]

Long-lived assets

0

[2],[3]

0

[2],[3]

Other [Member]

Segment Reporting Information [Line Items]

Net sales

157.3

[1],[2]

157.5

[1],[2]

146.7

[1],[2]

Long-lived assets

$14.70

[2],[3]

$18.20

[2],[3]

$14.70

[2],[3]

$18.20

[2],[3]

[1]

Net sales attributed to the geographic area are based on the location of the manufacturing facility, except for Japan, which was a sales office and included in the divestiture of the Advance Materials business.

[2]

All results and balances related to the UPC business are excluded for all periods presented.

[3]

Long-lived assets consists of property, plant and equipment, net.

Quarterly_Results_of_Operation2

Quarterly Results of Operations (Unaudited) (Schedule of Quarterly Results of Operations) (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Schedule of Selected Quarterly Financial Information [Line Items]
Net sales	$245,400,000	$262,900,000	$297,500,000	$261,700,000	$270,500,000	$265,700,000	$279,500,000	$341,800,000	$1,067,500,000	[1],[2]	$1,157,500,000	[1],[2]	$1,544,400,000	[1],[2]
Gross profit	50,600,000	62,600,000	63,100,000	61,900,000	54,600,000	65,900,000	63,800,000	74,200,000	238,200,000		258,400,000		243,600,000
Amounts attributable to OM Group, Inc. common stockholders:
Loss from continuing operations, net of tax	-189,000,000	6,300,000	5,100,000	5,300,000	17,300,000	12,400,000	8,100,000	-109,500,000	-172,300,000		-71,700,000		-38,300,000
Loss from discontinued operations, net of tax	0	100,000	-300,000	-100,000	-100,000	-300,000	-11,400,000	-500,000	-300,000		-12,300,000		-400,000
Loss attributable to OM Group, Inc. common stockholders	-189,000,000	6,400,000	4,800,000	5,200,000	17,200,000	12,100,000	-3,300,000	-110,000,000	-172,600,000		-84,000,000		-38,700,000
Net Income (loss) per common share - basic
Loss from continuing operations attributable to OM Group, Inc. common stockholders (in dollars per share)	($6.24)	$0.20	$0.16	$0.17	$0.54	$0.40	$0.26	($3.47)	($5.54)		($2.27)		($1.21)
Loss from discontinued operations attributable to OM Group, Inc. common stockholders (in dollars per share)	$0	$0.01	($0.01)	$0	$0	($0.01)	($0.36)	($0.02)	($0.01)		($0.39)		($0.01)
Net loss attributable to OM Group, Inc. common stockholders (in dollars per share)	($6.24)	$0.21	$0.15	$0.17	$0.54	$0.39	($0.10)	($3.49)	($5.55)		($2.66)		($1.22)
Net income (loss) per common share - assuming dilution
Loss from continuing operations attributable to OM Group, Inc. common stockholders (in dollars per share)	($6.24)	$0.20	$0.16	$0.16	$0.54	$0.39	$0.26	($3.46)	($5.54)		($2.27)		($1.21)
Loss from discontinued operations attributable to OM Group, Inc. common stockholders (in dollars per share)	$0	$0	($0.01)	$0	$0	($0.01)	($0.36)	($0.02)	($0.01)		($0.39)		($0.01)
Loss attributable to OM Group, Inc. common stockholders (in dollars per share)	($6.24)	$0.20	$0.15	$0.16	$0.54	$0.38	($0.10)	($3.48)	($5.55)		($2.66)		($1.22)
Loss on divestiture of advance materials business									-1,700,000		111,600,000		0
Cost Reductions Initiatives									10,000,000
Goodwill and intangible asset impairment charges									195,400,000		0		0
Adjustment to contingent consideration									0		13,000,000		0
Rahu Catalytics Limited [Member]
Net income (loss) per common share - assuming dilution
Adjustment to contingent consideration					13,000,000
Advanced Materials [Member]
Schedule of Selected Quarterly Financial Information [Line Items]
Net sales									102,600,000		166,300,000		447,000,000
Net income (loss) per common share - assuming dilution
Loss on divestiture of advance materials business								111,600,000			111,600,000
Magnetic Technologies [Member]
Schedule of Selected Quarterly Financial Information [Line Items]
Net sales									495,000,000		522,600,000		631,600,000
Net income (loss) per common share - assuming dilution
Cost Reductions Initiatives	1,600,000	300,000			400,000	700,000	400,000	3,800,000	1,900,000		5,400,000
Goodwill and intangible asset impairment charges									195,400,000
Battery Technologies [Member]
Schedule of Selected Quarterly Financial Information [Line Items]
Net sales									153,800,000		150,300,000		143,000,000
Net income (loss) per common share - assuming dilution
Severance costs						100,000
Cost Reductions Initiatives		2,600,000					500,000	200,000	2,600,000		800,000
Settlement charge									3,200,000
Ultra Pure Chemicals [Member]
Net income (loss) per common share - assuming dilution
Loss on disposal of business (net of tax)							9,800,000
Corporate [Member]
Net income (loss) per common share - assuming dilution
Cost Reductions Initiatives	100,000	100,000			1,400,000	1,000,000			200,000		2,400,000
Specialty Chemicals [Member]
Schedule of Selected Quarterly Financial Information [Line Items]
Net sales									316,100,000	[3]	318,600,000	[3]	323,600,000	[3]
Net income (loss) per common share - assuming dilution
Cost Reductions Initiatives	$700,000	$1,000,000	$400,000				$1,100,000		$2,100,000		$1,100,000
[1]	Net sales attributed to the geographic area are based on the location of the manufacturing facility, except for Japan, which was a sales office and included in the divestiture of the Advance Materials business.
[2]	All results and balances related to the UPC business are excluded for all periods presented.
[3]	All results related to the UPC business are excluded from the Specialty Chemicals segment for all periods presented.

Subsequent_Events_Details

Subsequent Events (Details) (USD $)	12 Months Ended	34 Months Ended
	Dec. 31, 2014	Dec. 31, 2017
Subsequent Event [Line Items]
Cost reductions initiatives	$10,000,000
Subsequent Event [Member] | Scenario, Forecast [Member] | Minimum [Member]
Subsequent Event [Line Items]
Cost reductions initiatives		50,000,000
Cost reduction annualized benefits		30,000,000
Subsequent Event [Member] | Scenario, Forecast [Member] | Maximum [Member]
Subsequent Event [Line Items]
Cost reductions initiatives		65,000,000
Cost reduction annualized benefits		$40,000,000

Schedule_II_Valuation_and_Qual1

Schedule II - Valuation and Qualifying Accounts (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$25.30		$10.70		$10.50
Acquisitions/Divestitures	0		-1		0
Charged (Credited) to Costs and Expenses	0.5		16.5		1
Charged (Credited) to Other Accounts	-17.9		-0.2		0.1
Deductions	-1.2		-0.7		-0.9
Balance at End of Year	6.7		25.3		10.7
Allowance for doubtful accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	3.9		5.2		4.8
Acquisitions/Divestitures	0	[1]	-1	[1]	0
Charged (Credited) to Costs and Expenses	0.3	[2]	0.2	[2]	0.7	[2]
Charged (Credited) to Other Accounts	-1.2	[3]	-0.2	[4]	0.1	[4]
Deductions	-0.5	[5]	-0.3	[5]	-0.4	[5]
Balance at End of Year	2.5		3.9		5.2
Allowance for note receivable [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	19.1		3.1		3.1
Acquisitions/Divestitures	0		0		0
Charged (Credited) to Costs and Expenses	0	[2]	16	[6]	0	[2]
Charged (Credited) to Other Accounts	-16.7	[7]	0		0
Deductions	0		0		0
Balance at End of Year	2.4		19.1		3.1
Environmental reserve [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	2.3		2.4		2.6
Acquisitions/Divestitures	0		0		0
Charged (Credited) to Costs and Expenses	0.2	[8]	0.3	[8]	0.3	[8]
Charged (Credited) to Other Accounts	0		0	[4]	0	[4]
Deductions	-0.7	[9]	-0.4	[9]	-0.5	[9]
Balance at End of Year	$1.80		$2.30		$2.40
[1]	Resulting from sale of AM and UPC businesses during 2013.
[2]	Provision for uncollectible accounts and notes receivable included in selling, general and administrative expenses.
[3]	Foreign currency translation adjustment and minor balance sheet reclassification.
[4]	Foreign currency translation adjustment.
[5]	Actual accounts written-off against the allowance.
[6]	Note receivable fully reserved at time of sale of cobalt business on March 29, 2013.
[7]	Relief of note receivable obligation in accordance with compliance on the cobalt supply agreement.
[8]	Provision for environmental costs included in selling, general and administrative expenses.
[9]	Actual cash expenditures charged against the accrual.