Significant Accounting Policies (Policies)	12 Months Ended
Dec. 31, 2011
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation — The consolidated financial statements include the accounts of OM Group, Inc. (the “Company”) and its consolidated subsidiaries. Intercompany accounts and transactions have been eliminated in consolidation. The Company has a 55% interest in a joint venture (“GTL”) that has a smelter in the Democratic Republic of Congo (the “DRC”). The joint venture is consolidated because the Company has a controlling interest in the joint venture. Noncontrolling interest is recorded for the remaining 45% interest.
Use of Estimates	Use of Estimates — The preparation of financial statements, in conformity with U.S. generally accepted accounting principles, 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.
Revenue Recognition	Revenue Recognition — Except for revenue recognized under the percentage of completion method of accounting in Battery Technologies (see discussion below), the Company recognizes 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. The Battery Technologies segment uses the percentage of completion method to recognize the majority of its revenue. The majority of defense contracts use the units-of-delivery method while the majority of aerospace 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 managements’ 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. Changes in cost estimates are recognized in the period of change and reflect the cumulative change from inception of the contract. These adjustments have historically not been material. 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. The Company collects and remits taxes assessed by different governmental authorities that are both imposed on and concurrent with revenue producing transactions between the Company and its customers. These taxes may include sales, use and value-added taxes. The Company reports the collection of these taxes on a net basis (excluded from revenues). All amounts in a sales transaction billed to a customer related to shipping and handling are reported as revenues.
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.
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts — The Company has recorded an allowance for doubtful accounts to reduce accounts receivable to 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 evident that collections will not occur. Trade credit is generally extended on a short-term basis; thus 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. The Company believes the average cost method provides for a better matching of inventory costs with related sales based on Magnetic Technologies' manufacturing process. The remaining inventory held by the Company is valued using 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 cobalt, nickel and rare earth materials can have a significant impact on inventory valuation. The Company evaluates the need for a lower of cost or market (“LCM”) adjustment to inventories based on the selling prices of its finished products. Declines in the selling prices of the Company's finished goods, which can result from decreases in the market price of raw materials or other factors, can result in the Company's inventory carrying value being written down to a lower market value. For cobalt metal re-sale inventory and inventory for which sales prices are highly correlated to cobalt prices (primarily in the Advanced Materials segment), volatile cobalt prices can have a significant impact on the LCM calculation. Fluctuations in the price of cobalt have been significant in the past and may be significant in the future. When evaluating whether such cobalt-based inventory is stated at the lower of cost or market, the Company generally considers cobalt reference prices at the end of the period. However, to the extent cobalt prices increase subsequent to the balance sheet date but before issuance of the financial statements, the Company considers these price movements in its LCM evaluation and determination of net realizable value (“NRV”). To the extent such price increases have an impact on the NRV of the Company’s inventory as of the balance sheet date, the Company will use the higher prices in its calculation so as not to recognize a loss when an actual loss will not be realized.
Receivable from Joint Venture Partners and Noncontrolling Interests	Receivables from Joint Venture Partners and Noncontrolling Interests — The noncontrolling interest in GTL is owned by two partners at 25% and 20%, respectively. In years prior to 2009, the Company refinanced the capital contribution for the 25% shareholder. At December 31, 2011 and 2010, the notes receivable, net balance from this partner was $16.0 million and $13.9 million, respectively. Due to the uncertainty of collection, the Company continues to record a full allowance against unpaid interest receivable under the notes receivable. Under the terms of the note receivable, 80% of the partner’s share of any dividends from the joint venture and other cash flow distributions paid by the joint venture, if any, first serve to reduce the notes receivable before any amounts are remitted to the joint venture partner. The note receivable is secured by 80% of the partner’s interest in the joint venture. The Company currently anticipates that repayment of the note receivable, net of the reserve, will be made from the partner’s share of dividends and return of capital from the joint venture.
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 — The Company evaluates 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 method. Indefinite-lived intangible assets consist of trade names.
Retained Liabilities of Business Sold	Retained Liabilities of Businesses Sold — Retained liabilities of businesses sold include obligations of the Company related to its former Precious Metals Group (“PMG”), which was sold in 2003. Under terms of the sale agreement, the Company 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 the Company owned PMG.
Research and Development	Research and Development — Research and development costs are charged to expense when incurred, are included in selling, general and administrative expenses
Repairs and Maintenance	Repairs and Maintenance — The Company expenses repairs and maintenance costs, including periodic maintenance shutdowns at its manufacturing facilities, when incurred.
Accounting for Leases	Accounting for 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 step rent provisions and escalation clauses, which are recognized 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. They are taken into account in computing our minimum lease payments and the minimum lease payments are recognized 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 the majority of the Company’s 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 weighted average exchange rates. The resulting translation adjustments are recorded as a component of Accumulated other comprehensive income (loss) in stockholders’ equity. The functional currency for the Company’s Finnish subsidiary and related DRC operations is the U.S. dollar because a majority of their purchases and sales are denominated in U.S. dollars. 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 — The Company enters 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 the Company’s 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, 2011 and 2010. 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. The Company, from time to time, employs 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 the Company may use a derivative to mitigate price risk. While this hedging may limit the Company’s ability to participate in gains from favorable commodity price fluctuations, it eliminates the risk of loss from adverse commodity price fluctuations. Periodically, the Company enters 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.
Reclassification	Reclassification — Certain reclassifications have been made to prior periods to conform to the current year presentation. Specifically, we have reclassified restructuring charges previously reported separately that are now reported as a component of cost of goods sold or selling, general and administrative expenses. These reclassifications had no impact on previously reported operating profit (loss) or net income (loss).

Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2011

Principles of Consolidation — The consolidated financial statements include the accounts of OM Group, Inc. (the “Company”) and its consolidated subsidiaries. Intercompany accounts and transactions have been eliminated in consolidation. The Company has a 55% interest in a joint venture (“GTL”) that has a smelter in the Democratic Republic of Congo (the “DRC”). The joint venture is consolidated because the Company has a controlling interest in the joint venture. Noncontrolling interest is recorded for the remaining 45% interest.

Use of Estimates

Use of Estimates — The preparation of financial statements, in conformity with U.S. generally accepted accounting principles, 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.

Revenue Recognition

Revenue Recognition — Except for revenue recognized under the percentage of completion method of accounting in Battery Technologies (see discussion below), the Company recognizes 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.

The Battery Technologies segment uses the percentage of completion method to recognize the majority of its revenue. The majority of defense contracts use the units-of-delivery method while the majority of aerospace 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 managements’ 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. Changes in cost estimates are recognized in the period of change and reflect the cumulative change from inception of the contract. These adjustments have historically not been material. 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.

The Company collects and remits taxes assessed by different governmental authorities that are both imposed on and concurrent with revenue producing transactions between the Company and its customers. These taxes may include sales, use and value-added taxes. The Company reports the collection of these taxes on a net basis (excluded from revenues).

All amounts in a sales transaction billed to a customer related to shipping and handling are reported as revenues.

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.

Allowance for Doubtful Accounts

Allowance for Doubtful Accounts — The Company has recorded an allowance for doubtful accounts to reduce accounts receivable to 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 evident that collections will not occur. Trade credit is generally extended on a short-term basis; thus 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. The Company believes the average cost method provides for a better matching of inventory costs with related sales based on Magnetic Technologies' manufacturing process. The remaining inventory held by the Company is valued using 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 cobalt, nickel and rare earth materials can have a significant impact on inventory valuation. The Company evaluates the need for a lower of cost or market (“LCM”) adjustment to inventories based on the selling prices of its finished products. Declines in the selling prices of the Company's finished goods, which can result from decreases in the market price of raw materials or other factors, can result in the Company's inventory carrying value being written down to a lower market value.

For cobalt metal re-sale inventory and inventory for which sales prices are highly correlated to cobalt prices (primarily in the Advanced Materials segment), volatile cobalt prices can have a significant impact on the LCM calculation. Fluctuations in the price of cobalt have been significant in the past and may be significant in the future. When evaluating whether such cobalt-based inventory is stated at the lower of cost or market, the Company generally considers cobalt reference prices at the end of the period. However, to the extent cobalt prices increase subsequent to the balance sheet date but before issuance of the financial statements, the Company considers these price movements in its LCM evaluation and determination of net realizable value (“NRV”). To the extent such price increases have an impact on the NRV of the Company’s inventory as of the balance sheet date, the Company will use the higher prices in its calculation so as not to recognize a loss when an actual loss will not be realized.

Receivable from Joint Venture Partners and Noncontrolling Interests

Receivables from Joint Venture Partners and Noncontrolling Interests — The noncontrolling interest in GTL is owned by two partners at 25% and 20%, respectively. In years prior to 2009, the Company refinanced the capital contribution for the 25% shareholder. At December 31, 2011 and 2010, the notes receivable, net balance from this partner was $16.0 million and $13.9 million, respectively. Due to the uncertainty of collection, the Company continues to record a full allowance against unpaid interest receivable under the notes receivable.

Under the terms of the note receivable, 80% of the partner’s share of any dividends from the joint venture and other cash flow distributions paid by the joint venture, if any, first serve to reduce the notes receivable before any amounts are remitted to the joint venture partner. The note receivable is secured by 80% of the partner’s interest in the joint venture.

The Company currently anticipates that repayment of the note receivable, net of the reserve, will be made from the partner’s share of dividends and return of capital from the joint venture.

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 — The Company evaluates 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 method. Indefinite-lived intangible assets consist of trade names.

Retained Liabilities of Business Sold

Retained Liabilities of Businesses Sold — Retained liabilities of businesses sold include obligations of the Company related to its former Precious Metals Group (“PMG”), which was sold in 2003. Under terms of the sale agreement, the Company 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 the Company owned PMG.

Research and Development

Research and Development — Research and development costs are charged to expense when incurred, are included in selling, general and administrative expenses

Repairs and Maintenance

Repairs and Maintenance — The Company expenses repairs and maintenance costs, including periodic maintenance shutdowns at its manufacturing facilities, when incurred.

Accounting for Leases

Accounting for 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 step rent provisions and escalation clauses, which are recognized 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. They are taken into account in computing our minimum lease payments and the minimum lease payments are recognized 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 the majority of the Company’s 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 weighted average exchange rates. The resulting translation adjustments are recorded as a component of Accumulated other comprehensive income (loss) in stockholders’ equity. The functional currency for the Company’s Finnish subsidiary and related DRC operations is the U.S. dollar because a majority of their purchases and sales are denominated in U.S. dollars. 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 — The Company enters 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 the Company’s 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, 2011 and 2010. 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.

The Company, from time to time, employs 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 the Company may use a derivative to mitigate price risk. While this hedging may limit the Company’s ability to participate in gains from favorable commodity price fluctuations, it eliminates the risk of loss from adverse commodity price fluctuations.

Periodically, the Company enters 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.

Reclassification

Reclassification — Certain reclassifications have been made to prior periods to conform to the current year presentation. Specifically, we have reclassified restructuring charges previously reported separately that are now reported as a component of cost of goods sold or selling, general and administrative expenses. These reclassifications had no impact on previously reported operating profit (loss) or net income (loss).