Stillwater Mining (SWC) 10-Q 1 May 14 2014 Q1 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	3 Months Ended
	Mar. 31, 2014	Apr. 28, 2014
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	31-Mar-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Entity Registrant Name	'STILLWATER MINING CO /DE/	'
Entity Central Index Key	'0000931948	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	119,800,787

Consolidated_Statements_Of_Com

Consolidated Statements Of Comprehensive Income (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
REVENUES	'	'
Mine Production	$125,729	$128,314
PGM Recycling	93,535	122,334
Other	235	0
Total revenues	219,499	250,648
Costs of metals sold	'	'
Mine Production	77,992	75,753
PGM Recycling	90,706	116,862
Other	79	0
Total costs of metals sold (excludes depletion, depreciation and amortization)	168,777	192,615
Depletion, depreciation and amortization	'	'
Mine Production	14,910	15,025
PGM Recycling	241	258
Total depletion, depreciation and amortization	15,151	15,283
Total costs of revenues	183,928	207,898
Marketing	151	1,727
Exploration	1,046	5,951
Research and development	31	63
General and administrative	9,604	15,187
Loss on long-term investments	0	562
(Gain)/Loss on disposal of property, plant and equipment	-238	36
Total costs and expenses	194,522	231,424
OPERATING INCOME	24,977	19,224
OTHER INCOME (EXPENSE)	'	'
Other	33	1,145
Interest income	825	1,200
Interest expense	-5,850	-6,652
Foreign currency transaction gain, net	4,179	4,237
INCOME BEFORE INCOME TAX PROVISION	24,164	19,154
Income tax provision	-5,125	-4,850
NET INCOME	19,039	14,304
Net loss attributable to noncontrolling interest	-533	-279
NET INCOME ATTRIBUTABLE TO COMMON STOCKHOLDERS	19,572	14,583
Other comprehensive (loss) income, net of tax	'	'
Net unrealized (losses)/gains on investments available-for-sale	-37	74
COMPREHENSIVE INCOME ATTRIBUTABLE TO COMMON STOCKHOLDERS	19,535	14,657
Comprehensive loss attributable to noncontrolling interest	-533	-279
TOTAL COMPREHENSIVE INCOME	$19,002	$14,378
Weighted average common shares outstanding	'	'
Basic (in shares)	119,608	117,433
Diluted (in shares)	155,754	159,695
Basic earnings per share attributable to common stockholders (in usd per share)	$0.16	$0.12
Diluted earnings per share attributable to common stockholders (in usd per share)	$0.15	$0.12

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets	'	'
Cash and cash equivalents	$224,624	$286,687
Investments, at fair market value	249,630	209,338
Inventories	165,336	158,650
Trade receivables	28,871	8,988
Deferred income taxes	18,855	21,547
Prepaids	1,873	3,912
Other current assets	19,993	14,757
Total current assets	709,182	703,879
Mineral properties	159,252	159,252
Mine development, net	357,676	346,346
Property, plant and equipment, net	121,421	124,731
Deferred debt issuance costs	7,581	7,945
Other noncurrent assets	3,738	4,527
Total assets	1,358,850	1,346,680
Current liabilities	'	'
Accounts payable	21,668	32,088
Accrued compensation and benefits	29,486	30,646
Property, production and franchise taxes payable	12,867	14,495
Current portion of long-term debt and capital lease obligations	2,062	2,035
Income taxes payable	6,099	4,416
Other current liabilities	8,967	5,368
Total current liabilities	81,149	89,048
Long-term debt and capital lease obligations	312,245	308,667
Deferred income taxes	70,099	79,159
Accrued workers compensation	5,998	6,031
Asset retirement obligation	8,835	8,654
Other noncurrent liabilities	9,960	7,262
Total liabilities	488,286	498,821
Stockholders’ equity	'	'
Preferred stock, $0.01 par value, 1,000,000 shares authorized; none issued	0	0
Common stock, $0.01 par value, 200,000,000 shares authorized; 119,726,425 and 119,466,449 shares issued and outstanding	1,197	1,195
Paid-in capital	1,079,901	1,076,200
Accumulated deficit	-229,864	-249,436
Accumulated other comprehensive (loss) income	-31	6
Total stockholders’ equity	851,203	827,965
Noncontrolling interest	19,361	19,894
Total equity	870,564	847,859
Total liabilities and equity	$1,358,850	$1,346,680

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]	'	'
Preferred stock, par value (in usd per share)	$0.01	$0.01
Preferred stock, shares authorized (in shares)	1,000,000	1,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in usd per share)	$0.01	$0.01
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	119,726,425	119,466,449
Common stock, shares outstanding (in shares)	119,726,425	119,466,449

Consolidated_Statements_Of_Cas

Consolidated Statements Of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES	'	'
Net income	$19,039	$14,304
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depletion, depreciation and amortization	15,151	15,283
(Gain)/Loss on disposal of property, plant and equipment	-238	36
Loss on long-term investments	0	562
Amortization/accretion on investment premium/ discount	574	885
Deferred taxes	-2,131	1,830
Foreign currency transaction gain, net	-4,179	-4,237
Accretion of asset retirement obligation	181	167
Amortization of debt issuance costs	364	557
Accretion of convertible debenture debt discount	4,170	3,832
Share based compensation and other benefits	3,180	4,246
Non-cash capitalized interest	-679	-422
Changes in operating assets and liabilities:	'	'
Inventories	-6,133	-34,017
Trade receivables	-19,883	-4,350
Prepaids	2,039	665
Accrued compensation and benefits	-1,164	-780
Accounts payable	-7,579	11,567
Property, production and franchise taxes payable	1,070	1,612
Income taxes payable	1,683	669
Workers compensation	-33	384
Other operating assets	-4,234	1,346
Other operating liabilities	3,567	1,363
NET CASH PROVIDED BY OPERATING ACTIVITIES	4,765	15,502
CASH FLOWS FROM INVESTING ACTIVITIES	'	'
Capital expenditures	-26,133	-29,406
Proceeds from disposal of property, plant and equipment	259	19
Purchases of investments	-76,352	-21,996
Proceeds from maturities of investments	35,419	24,025
NET CASH USED IN INVESTING ACTIVITIES	-66,807	-27,358
CASH FLOWS FROM FINANCING ACTIVITIES	'	'
Payments on debt and capital lease obligations	-557	-164,787
Issuance of common stock	536	56
NET CASH USED IN FINANCING ACTIVITIES	-21	-164,731
CASH AND CASH EQUIVALENTS	'	'
Net decrease	-62,063	-176,587
Balance at beginning of period	286,687	379,680
BALANCE AT END OF PERIOD	$224,624	$203,093

General

General	3 Months Ended
	Mar. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
General	'
	GENERAL
	In the opinion of management, the accompanying unaudited consolidated financial statements contain all adjustments (consisting only of normal recurring adjustments) necessary to present fairly the financial position of Stillwater Mining Company (the “Company”) as of March 31, 2014, the results of its operations and its cash flows for the three-month periods ended March 31, 2014 and 2013. The results of operations for the first three months of 2014 are not necessarily indicative of the results to be expected for the full year. The accompanying consolidated financial statements in this quarterly report should be read in conjunction with the consolidated financial statements and notes thereto included in the Company's 2013 Annual Report on Form 10-K. All intercompany transactions and balances have been eliminated in consolidation.
	The preparation of the Company’s consolidated financial statements in conformity with United States generally accepted accounting principles (U. S. GAAP) requires management to make estimates and assumptions that affect the amounts reported in these consolidated financial statements and accompanying notes. The more significant areas requiring the use of management’s estimates relate to mineral reserves, reclamation and environmental obligations, valuation allowance for deferred tax assets, useful lives utilized for depreciation, amortization and accretion calculations, future cash flows from long-lived assets, and fair value of derivatives and other financial instruments. Actual results could differ from these estimates.
	The Company reclassified various items for the period ended March 31, 2013 for presentation purposes within the operating activities of the Company's, Consolidated Statements of Cash Flows.
	The Company evaluates subsequent events through the date the consolidated financial statements are issued. Subsequent to the first quarter of 2014 of the Company initiated a restructuring process that impacted positions at various levels within the organization. As a result, it is estimated that restructuring costs of approximately $4.3 million (before tax) will be recognized in the second quarter of 2014.

Sales

Sales	3 Months Ended
	Mar. 31, 2014
Sales Revenue, Goods, Net [Abstract]	'
Sales	'
	SALES
	MINE PRODUCTION
	The Company mines and processes ores from its Montana operations containing palladium, platinum, rhodium, gold, silver, copper and nickel into intermediate and final products for sale to customers. Palladium, platinum, rhodium, gold and silver are sent to third party refineries for final processing from where they are sold to a number of consumers and dealers with whom the Company has established trading relationships. Refined platinum group metals (PGMs) of 99.95% purity (rhodium of 99.9%) in sponge form are transferred upon sale from the Company’s account at third party refineries to the account of the purchaser. By-product metals are normally sold at market prices to customers, brokers or outside refiners. By-products of copper and nickel are produced by the Company at less than commercial grade, so prices for these metals typically reflect a quality discount. By-product sales are included in revenues from Mine Production. During the first quarters of 2014 and 2013, total by-product (copper, nickel, gold, silver and mined rhodium) sales were $6.7 million and $7.5 million, respectively.
	All Company sales of mined PGMs are either in the spot market or under mutually agreed short-term (less than one year) supply agreements.
	Revenue is recognized when persuasive evidence of an arrangement exists, delivery has occurred either physically or through an irrevocable transfer of metals to customers’ accounts, the price is fixed or determinable, when no related obligations remain and collectability is probable.
	PGM RECYCLING
	The Company purchases spent catalyst material from third parties and processes this material in its facilities in Columbus, Montana, to recover palladium, platinum and rhodium for sale. It also accepts material supplied from third parties on a tolling basis, processing it for a fee and returning the recovered metals to the supplier. The Company has entered into sourcing arrangements for catalyst material with various suppliers. Under these sourcing arrangements as currently structured, the Company may advance cash against a shipment of material shortly before actually receiving the physical shipment. These advances are included in Other current assets on the Company’s Consolidated Balance Sheets until such time as the material has been physically received and title has transferred to the Company at which time the advance is reclassified into Inventories. Finance charges collected on advances and inventories prior to being earned are included in Other current liabilities on the Company’s Consolidated Balance Sheets. Finance charges are reclassified from Other current liabilities to Interest income ratably from the time the advance was made until the out-turn date of the inventory.
	At the same time the Company purchases recycling material, it typically enters into a fixed forward contract for future delivery of the PGMs contained in the recycled material at a price consistent with the purchase cost of the recycled material. The contract commits the Company to deliver finished metal on a specified date that normally corresponds to the expected out-turn date for the metal from the final refiner. The purpose of this arrangement is to eliminate the Company’s exposure to fluctuations in market prices during processing, while at the same time creating an obligation for the Company to deliver metal at a future point in time that could be subject to operational risks. If the Company is unable to complete the processing of the recycled material by the contractual delivery date, it either covers its delivery commitments with mine production or purchases finished metal in the open market. If open market purchases are used, the Company bears the risk of any changes in the market price relative to the price stipulated in the delivery contract.
	OTHER
	The Company recognized revenue of approximately $0.2 million, from the liquidation of its promotional jewelry inventory. This is shown as other revenue in the Consolidated Statements of Comprehensive Income.
	TOTAL SALES
	Total sales to significant customers as a percentage of total revenues for the three-month periods ended March 31, 2014 and 2013 were as follows:
		Three Months Ended March 31,
		2014(1)		2013(1)
	Customer A	33	%	14	%
	Customer B	22	%	26	%
	Customer C	11	%	—
	Customer D	—		16	%
	Customer E	—		16	%
		66	%	72	%
	(1) The “—” symbol represents less than 10% of total revenues.

Asset_Impairment

Asset Impairment	3 Months Ended
	Mar. 31, 2014
Asset Impairment Charges [Abstract]	'
Asset Impairment	'
	ASSET IMPAIRMENT
	The Company reviews and evaluates its long-lived assets for impairment when events and changes in circumstances indicate that the related carrying amounts of its assets may not be recoverable. Impairment is considered to exist if the total estimated future cash flows on an undiscounted basis are less than the carrying amount of the asset.
	The Company determined there were no material events or changes in circumstances requiring the Company to test long-lived assets for impairment at March 31, 2014. However, during the third quarter of 2013, the Company recorded a $290.4 million (before-tax) impairment in the carrying value of the Altar mineral property in Argentina, reducing the carrying value to its estimated fair market value of $102.0 million. At December 31, 2013, the Company recorded a $171.4 million (before-tax) impairment in the carrying value of the Marathon assets, reducing the carrying value to their estimated fair value of $57.2 million.

Noncontrolling_Interest

Noncontrolling Interest	3 Months Ended
	Mar. 31, 2014
Noncontrolling Interest [Abstract]	'
Noncontrolling Interest	'
	NONCONTROLLING INTEREST
	In 2012, the Company entered into an agreement with Mitsubishi Corporation (Mitsubishi) in which a Mitsubishi subsidiary acquired a 25% interest in the Company's wholly-owned subsidiary, Stillwater Canada Inc (SCI), which owns the Marathon PGM-copper project and related properties, for approximately $81.25 million in cash and contributed an additional $13.6 million to satisfy Mitsubishi's portion of the venture's initial cash call. Mitsubishi will be responsible for funding its 25% share of operating, capital and exploration expenditures on the Marathon properties and has agreed to cooperate and support efforts to secure project financing for Marathon. Mitsubishi will have an option to purchase up to 100% of Marathon's future PGM production under a related supply agreement at a small discount to market. The change in the parent company's equity as a result of the sale of the noncontrolling interest in SCI was an increase to Additional paid in capital of $42.5 million, offset in part by expenses incurred of $1.1 million.
	The noncontrolling interest's share of equity in SCI is reflected as Noncontrolling interest in the Company's Consolidated Balance Sheets and was $19.4 million as of March 31, 2014.

Derivative_Instruments

Derivative Instruments	3 Months Ended
	Mar. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Derivative Instruments	'
	DERIVATIVE INSTRUMENTS
	The Company uses various derivative financial instruments to manage its exposure to changes in interest rates and PGM market commodity prices. Some of these derivatives are designated as hedges. Because the Company hedges only with instruments that have a high correlation with the value of the underlying exposures, changes in the derivatives’ fair value are expected to be offset by changes in the value of the hedged transaction.
	COMMODITY DERIVATIVES
	The Company customarily enters into fixed forward contracts and on occasion enters into financially settled forward contracts to offset the price risk in its PGM recycling activity. From time to time, it has entered into these types of contracts on portions of its mine production. Under these fixed forward transactions, the Company agrees to deliver a stated quantity of metal on a specific future date at a price stipulated in advance. The Company uses fixed forward transactions primarily to price in advance the metals acquired for processing in its PGM Recycling segment. Under financially settled forward transactions, at each settlement date the Company receives the difference between the forward price and the market price if the market price is below the forward price and the Company pays the difference between the forward price and the market price if the market price is above the forward price. These financially settled forward contracts are settled in cash at maturity and do not require physical delivery of metal at settlement. The Company has typically used financially settled forward contracts with third parties to reduce its exposure to price risk on metal it is obligated to deliver under long-term sales agreements.
	MINE PRODUCTION
	At present, the Company has not entered into derivative instruments to hedge its mined production.
	PGM RECYCLING
	The Company customarily enters into fixed forward sales relating to PGM recycling of catalyst materials. The metals from PGM recycled materials are sold forward at the time of purchase and delivered against the fixed forward contracts when the ounces are recovered. Because the forward price is also used to determine the acquisition price, this arrangement significantly reduces exposure to PGM price volatility. The Company believes such transactions qualify for the exception to hedge accounting treatment and so has elected to account for these transactions as normal sales.
	All of the fixed forward sales contracts open at March 31, 2014 will settle at various periods through September 2014. The Company has credit agreements with its major trading partners that provide for margin deposits in the event that forward prices for metals exceed the Company’s hedged prices by a predetermined margin limit. As of March 31, 2014, no such margin deposits were outstanding or due.
	On occasion, the Company has entered into financially settled forward contracts on its recycled materials. Such contracts are utilized when the Company wishes to establish a firm forward price for recycled metal on a specific future date. No financially settled forward contracts were outstanding during the three-month periods ended March 31, 2014 and 2013. The Company generally has not designated these contracts as cash flow hedges, so they are marked to market at the end of each accounting period. The change in the fair value of the derivatives is reflected in the Company's Consolidated Statements of Comprehensive Income.
	The following is a summary of the Company's commodity derivatives in place as of March 31, 2014:
	PGM Recycling:
	Fixed Forwards	Platinum			Palladium			Rhodium
	Settlement Period	Ounces	Average		Ounces	Average		Ounces	Average
			Price			Price			Price
	Second Quarter 2014	30,523	$	1,424	51,033	$	743	7,018	$	1,014
	Third Quarter 2014	5,464	$	1,449	5,965	$	774	2,158	$	1,075

ShareBased_Compensation

Share-Based Compensation	3 Months Ended
	Mar. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Share-Based Compensation	'
	SHARE-BASED COMPENSATION
	STOCK PLANS
	The Company sponsors stock plans (the “Plans”) that enable the Company to grant stock options or other equity based compensation to employees and non-employee directors. Effective March 2011, the Company ceased offering stock options as incentive compensation to employees and non-employee directors, and began to issue only cash awards or restricted stock units in lieu of stock options. The Company continues to have previously issued stock options that remain outstanding under two separate plans: the General Employee Plan and the 2004 Equity Incentive Plan. In April 2012, the Company's stockholders approved the 2012 Equity Incentive Plan. At inception of the plans, approximately 16.4 million shares of common stock were authorized for issuance under the Plans, including approximately 5.0 million, 5.2 million, 1.4 million and 4.8 million authorized shares for the 2012 Equity Incentive Plan, 2004 Equity Incentive Plan, the General Employee Plan and the 1994 Incentive Plan (as amended by the 1998 Incentive Plan), respectively. The 1998 Incentive Plan and the General Employee Plan have been terminated and no additional options, shares or units may be issued under these two terminated plans. Approximately 4.4 million shares were available and reserved for grant under the 2012 Equity Incentive Plan as of March 31, 2014.
	The Compensation Committee of the Company’s Board of Directors administers the Plans and determines the type of equity awards to be issued, the exercise period, vesting period and all other terms of instruments issued under the Plans. Employees’ options and time-based restricted stock units vest in equal annual installments over a three-year period after date of grant. Options expire ten years after the date of grant. Certain of the Company's equity incentive plans and award agreements contain "change in control" provisions which provide that, among other triggering events, a "change in control" occurs if following the election of new directors to the Board of Directors, a majority of the members of the Board of Directors are not considered "incumbent directors."
	The Company recognizes compensation expense associated with its stock option grants based on their fair market value on the date of grant as determined, using a Black-Scholes option pricing model. Unless vesting is accelerated due to a change in control or other event, the Company recognizes stock option expense ratably over the vesting period of the options. If options are canceled or forfeited prior to vesting, the Company stops recognizing the related expense effective with the date of forfeiture.
	There was no compensation expense associated with stock option grants recorded for the three-month period ended March 31, 2014. All outstanding, unvested stock options vested in the second quarter of 2013, compensation expense related to the fair value of stock options during the three-month period ended March 31, 2013, was approximately $11,000. The compensation expense for prior periods was recorded in General and administrative in the Company's Consolidated Statements of Comprehensive Income. The Company received approximately $0.5 million in cash from the exercise of stock options in the three-month period ended March 31, 2014, and less than $0.1 million in the comparable period in 2013.
	NONVESTED SHARES
	Time-Based and Performance-Based Restricted Stock Unit Awards
	The 2012 Equity Incentive Plan allows for the grant of time-based and performance-based restricted stock unit awards. A performance-based restricted stock unit award provides the participant with the right to receive a number of shares of the Company's stock depending on achievement of specific measurable performance criteria. In the period it becomes probable that the performance criteria will be achieved, the Company recognizes expense for the proportionate share of the total fair value of the grant related to the vesting period that has already lapsed. The remaining cost of the grant is expensed over the balance of the vesting period. In the event the Company determines it is no longer probable that it will achieve the minimum performance criteria specified in the Plan, the Company reverses all of the previously recognized compensation expense in the period such a determination is made. Time-based and performance-based awards are not entitled to any dividend equivalents with respect to the restricted stock units nor any dividends on stock that may be delivered in settlement of the restricted stock units unless and until the stock is issued in settlement of the restricted stock units.
	The following table summarizes the status of and changes in the Company’s nonvested shares during the first three months of 2014:
		Nonvested Shares		Weighted-Average Grant-Date Fair Value
	Nonvested shares at January 1, 2014	31,057		$	11.55
	Granted	563,375		14.66
	Vested	—		—
	Forfeited	(200	)	11.81
	Nonvested shares at March 31, 2014	594,232		$	14.5
	As of March 31, 2014, the Company had outstanding nonvested time-based and performance-based restricted stock units of 370,820 and 223,412, respectively. Total compensation expense related to grants of nonvested shares was $0.2 million and $1.7 million in each of the three- month periods ended March 31, 2014 and 2013, respectively.
	The following table presents the compensation expense of the nonvested shares outstanding at March 31, 2014 to be recognized over the remaining vesting periods:
	(In millions)	Compensation Expense
	Remaining 2014	$	2.3
	2015	2.9
	2016	2.9
	2017	0.3
	Total	$	8.4

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	INCOME TAXES
	The Company determines income taxes using the asset and liability method which results in the recognition of deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the carrying amount and the tax basis of those assets and liabilities, as well as operating loss and tax carryforwards, using enacted tax rates in effect in the years in which the differences are expected to reverse. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. Deferred tax assets and liabilities are recorded on a jurisdictional basis.
	At March 31, 2014, the Company has approximately $125.2 million of regular federal tax net operating loss carryforwards in the U.S. expiring from 2020 through 2028. Usage of $89.4 million of these net operating losses is limited to approximately $10.2 million annually as a result of the change in control of the Company that occurred in connection with the Norilsk Nickel transaction in 2003. The Company has $30.5 million of alternative minimum tax credit carryforwards which will not expire and $1.2 million in general business credits expiring during 2031 to 2033. The Company has approximately $2.4 million of state tax net operating loss carryforwards expiring during 2020 through 2029. The Company also has $56.1 million of foreign net operating loss carryforwards. The foreign net operating losses expire as follows: $20.1 million during 2014 to 2019 and $26.4 million during 2024 to 2034. Currently, $9.6 million of foreign net operating losses have an indefinite life.
	In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. Management considers the scheduled reversal of deferred tax liabilities, projected future taxable income and tax planning strategies in making this assessment. The Company provided a valuation allowance in 2014 and 2013 to reflect the estimated amount of deferred tax assets which may not be realized, which principally relate to foreign and state net operating losses, capital losses, as well as certain tax credits.
	The provision for income taxes for the three-month periods ended March 31, 2014 and 2013, consists of U.S. Federal income tax, state tax expense, as well as deferred tax benefit from certain foreign jurisdictions. Changes in the Company’s net deferred tax assets and liabilities have been partially offset by a corresponding change in the valuation allowance. As a result of an analysis concluded during the year ended December 31, 2013, the Company determined it has tax exposure in certain states for which tax filings had not previously been made. Tax returns will be filed in such states for the tax years affected, and any unpaid taxes will be paid. This will also require the amendment of tax returns previously filed in Montana for the tax years affected. As of March 31, 2014, the tax provision impact of the unpaid tax, net of expense recorded including interest and penalties, associated with this matter is estimated at $1.8 million.
	The Company recognized an income tax provision of $5.1 million and $4.9 million for the three-month periods ended March 31, 2014 and 2013, respectively.
	The Company’s policy is to recognize interest and penalties on unrecognized tax benefits in Income tax provision in the Company's Consolidated Statements of Comprehensive Income. The interest and penalties accrued for the three-month period ended March 31, 2014 was $2.1 million. The Company made income tax payments of $1.2 million and $2.4 million in the three-month periods ended March 31, 2014 and 2013, respectively. Tax years still open for examination by the taxing authorities are the years ended December 31, 2013, 2012, 2011 and 2010, although net operating loss and credit carryforwards from all years are subject to examination and adjustments for the three years following the year in which the carryforwards are utilized.

Debt_and_Capital_Lease_Obligat

Debt and Capital Lease Obligations	3 Months Ended
	Mar. 31, 2014
Debt Disclosure [Abstract]	'
Debt and Capital Lease Obligations	'
	DEBT AND CAPITAL LEASE OBLIGATIONS
	1.875% CONVERTIBLE DEBENTURES
	In March 2008, the Company issued and sold $181.5 million aggregate principal amount of 1.875% senior unsecured convertible debentures due March 15, 2028, with interest payable semi-annually. Each $1,000 principal amount of the 1.875% debentures is initially convertible, at the option of the holders, into approximately 42.5351 shares of the Company’s common stock, at any time prior to the maturity date. The conversion rate is subject to certain adjustments, but will not be adjusted for accrued interest or any unpaid interest. The conversion rate initially represents a conversion price of $23.51 per share.
	In October 2009, the Company exchanged $15.0 million face amount of the 1.875% debentures for 1.84 million shares of the Company's common stock, leaving $166.5 million aggregate principal amount of the debentures outstanding at December 31, 2009. In March 2013, the holders of $164.3 million principal amount of the 1.875% debentures exercised their option to require the Company to redeem their 1.875% debentures at face value. Holders of the remaining $2.2 million of outstanding 1.875% debentures may require the Company to redeem their 1.875% debentures at face value on March 15, 2018 or March 15, 2023, or at any time before March 15, 2028, upon the occurrence of certain events. Effective as of March 22, 2013, the Company had the right at its discretion to redeem the remaining $2.2 million of outstanding 1.875% debentures for cash at any time prior to maturity. The outstanding balance at March 31, 2014, and December 31, 2013, is $2.2 million aggregate principal amount, reported as a long-term debt obligation.
	There was no amortization expense related to the issuance costs of the 1.875% debentures for the three-month period ended March 31, 2014, and for the same period of 2013 there was approximately $0.2 million of amortization expense. The interest expense on the 1.875% debentures was approximately $10,500 and $0.7 million for the three-month periods ended March 31, 2014 and 2013, respectively. The Company made cash payments of $21,000 and $1.6 million for interest on the 1.875% debentures for the three-month periods ended March 31, 2014 and March 31, 2013, respectively.
	1.75% CONVERTIBLE DEBENTURES
	In October 2012, the Company issued $396.75 million aggregate principal amount of 1.75% senior unsecured convertible debentures due October 15, 2032 (1.75% debentures). Each $1,000 principal amount of these 1.75% debentures is initially convertible, under certain circumstances and during certain periods, into 60.4961 shares (subject to customary anti-dilution adjustments) of the Company's common stock, which represents an initial conversion price of $16.53 per share. The 1.75% debentures also include an embedded conversion enhancement feature that is equivalent to including with each debenture a warrant initially exercisable for 30.2481 shares at $16.53 per share (also subject to customary anti-dilution adjustments). The Company, at its election, may settle conversions of the 1.75% debentures in cash, shares of its common stock or any combination of cash and shares of its common stock. Holders have the right to redeem their 1.75% debentures at face value plus accrued and unpaid interest on October 15 of each of 2019, 2024, 2029, and upon the occurrence of certain corporate events. The Company will have the right to redeem the 1.75% debentures at any time on or after October 20, 2019.
	The 1.75% debentures were bifurcated under U.S. GAAP into separate debt and equity components, and reflect an effective maturity (to the first optional redemption date) of seven years. The residual amount of $141.6 million recorded in equity is treated for accounting purposes as additional debt discount and accreted as an additional non-cash interest charge to earnings over the expected life. Debt and equity issuance costs totaling approximately $12.4 million were deducted from the gross proceeds of the offering of the 1.75% debentures and the debt portion is being amortized ratably over seven years.
	The 1.75% debentures have an effective interest rate of 8.50% and a stated interest rate of 1.75% with interest paid semi-annually. The balance outstanding at March 31, 2014, and December 31, 2013, was approximately $278.2 million and $274.0 million, respectively, which is net of unamortized discount of $118.6 million and $122.8 million, respectively.
	Amortization expense related to the issuance costs of the 1.75% debentures was approximately $0.3 million for the three-month periods ended March 31, 2014, and March 31, 2013, respectively. The interest expense was approximately $5.9 million and $5.6 million for the three-month periods ended March 31, 2014 and March 31, 2013, respectively. The Company made no interest payments on the 1.75% debentures during the three-month periods ended March 31, 2014, and March 31, 2013.
	EXEMPT FACILITY REVENUE BONDS
	During 2000, the Company completed a $30.0 million offering of 8.0% Exempt Facility Revenue Bonds, Series 2000 through the State of Montana Board of Investments. The bonds were issued by the State of Montana Board of Investments to finance a portion of the costs of constructing and equipping certain sewage and solid waste disposal facilities at both the Stillwater Mine and the East Boulder Mine. The bonds mature on July 1, 2020 and have a stated interest rate of 8.0% with interest paid semi-annually. Net discounted proceeds from the offering were $28.7 million, yielding an effective rate of 8.57%. The balance outstanding at March 31, 2014, and December 31, 2013, was $29.6 million, which is net of unamortized discount of $0.4 million. The Company made no interest payments on the revenue bonds for the three-month periods ended March 31, 2014 and 2013.
	ASSET-BACKED REVOLVING CREDIT FACILITY
	In December 2011, the Company signed a $100.0 million asset-backed revolving credit agreement incurring debt issuance costs of $1.1 million. In January 2012, the Company completed the syndication of this facility and simultaneously expanded its maximum line of credit to $125.0 million, incurring additional debt issuance costs of $0.2 million. Borrowings under this working capital credit facility are limited to a borrowing base equal to the sum of 85% of eligible accounts receivable and 70% of eligible inventories. Terms of the credit agreement state that the borrowings will be secured by the Company's accounts receivable, metals inventories and other accounts. The asset-backed revolving credit facility includes a single fixed-charge coverage covenant that only takes effect when less than 30% of the total borrowing capacity under the facility remains available. The facility includes a $60.0 million letter of credit sub-facility. Outstanding borrowings under the facility accrue interest at a spread over the London Interbank Offer Rate that varies from 2.25% to 2.75%, decreasing progressively as the percentage drawn under the facility increases. The Company also pays an unused capacity fee on committed but unutilized borrowing capacity available under the facility at a rate per annum of 0.375% or 0.5%, depending on utilization of the facility.
	The Company recognized $0.3 million in fees associated with the asset-backed revolving credit agreement in each of the three-month periods ended March 31, 2014 and 2013, respectively. Amortization expense related to the issuance costs of the credit agreement was less than $0.1 million for each of the three-month periods ended March 31, 2014 and 2013. As of March 31, 2014, there were no outstanding borrowings under this revolving credit facility and approximately $17.5 million in undrawn irrevocable letters of credit have been issued under this facility as collateral for sureties.
	CAPITAL LEASE OBLIGATIONS
	The Company entered into a lease agreement with General Electric Capital Corporation (GECC) covering the acquisition of a tunnel-boring machine (TBM) for use on the Blitz development adjacent to the Stillwater Mine. The transaction is structured as a capital lease with a four-year term maturing in 2016; lease payments are due quarterly in advance. The Company made cash payments of $0.5 million on its capital lease obligations in each of the three-month periods ended March 31, 2014 and 2013, respectively. The cash payments for each of the three-month periods ended March 31, 2014 and March 31, 2013 included interest of less than $0.1 million. As of March 31, 2014 and December 31, 2013, the outstanding balance under the capital lease was $4.1 million and $4.6 million, respectively.
	The following is a schedule, by year, of the future minimum lease payments for the capital lease together with the present value of the net minimum lease payments:
	(In thousands)
	Remaining 2014	$	1,625
	2015	2,168
	2016	590
	Total minimum lease payments	$	4,383
	Less interest at rates ranging from 5.21% to 5.46% (before-tax)	259
	Net minimum lease payments	$	4,124
	Less current portion	1,984
	Total long-term capital lease obligation	$	2,140
	CAPITALIZED INTEREST
	The Company capitalizes interest incurred on its various debt instruments as a cost of specific and identified projects under development. For the three-month periods ended March 31, 2014 and 2013, the Company capitalized interest of $1.1 million and $0.8 million, respectively. Capitalized interest is recorded as a reduction to Interest expense in the Company's Consolidated Statements of Comprehensive Income.

Mineral_Properties_and_Mine_De

Mineral Properties and Mine Development	3 Months Ended
	Mar. 31, 2014
Extractive Industries [Abstract]	'
Mineral Properties and Mine Development	'
	MINERAL PROPERTIES AND MINE DEVELOPMENT
	Mineral properties and mine development reflected in the accompanying balance sheets consisted of the following:
	(In thousands)	March 31,			December 31, 2013
		2014
	Mineral Properties:
	Montana, United States of America
	Stillwater Mine	$	1,950		$	1,950
	Ontario, Canada
	Marathon properties	50,915			50,915
	Coldwell Complex property	4,417			4,417
	San Juan, Argentina
	Altar property	101,970			101,970
	Mine Development:
	Montana, United States of America
	Stillwater Mine	$	549,940		$	532,480
	East Boulder Mine	183,697			179,263
		$	892,889		$	870,995
	Less accumulated depletion and amortization	(375,961		)	(365,397		)
	Total mineral properties and mine development	$	516,928		$	505,598

Property_Plant_and_Equipment

Property, Plant and Equipment	3 Months Ended
	Mar. 31, 2014
Property, Plant and Equipment [Abstract]	'
Property, Plant and Equipment	'
	PROPERTY, PLANT AND EQUIPMENT
	Property, plant and equipment reflected in the accompanying balance sheets consisted of the following:
	(In thousands)	March 31,			December 31, 2013
		2014
	Machinery and equipment	$	141,662		$	138,351
	Buildings and structural components	166,404			160,076
	Land	8,592			8,592
	Construction-in-progress:
	Stillwater Mine	1,541			5,818
	East Boulder Mine	904			1,057
	Marathon	402			402
	Processing facilities and other	2,886			5,841
		$	322,391		$	320,137
	Less accumulated depreciation	(200,970		)	(195,406		)
	Total property, plant, and equipment	$	121,421		$	124,731
	The Company's capital outlay for the three-month periods ended March 31, 2014 and 2013, was as follows:
	(In thousands)	March 31,			March 31
		2014			2013
	Stillwater Mine	$	18,485		$	18,522
	East Boulder Mine	6,375			6,138
	Marathon project	—			2,988
	Altar project	—			94
	Other	1,273			1,664
	Total capital outlay	$	26,133		$	29,406

Segment_Information

Segment Information	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Segment Information	'
	SEGMENT INFORMATION
	The Company operates five reportable business segments: Mine Production, PGM Recycling, Canadian Properties, South American Properties and All Other. These segments are managed separately based on fundamental differences in their operations and geographic separation.
	The Mine Production segment consists of two business components: the Stillwater Mine and the East Boulder Mine. The Mine Production segment is engaged in the development, extraction, processing and refining of PGMs. The Company sells PGMs from mine production under short-term and long-term sales agreements and in open PGM markets. The financial results for the Stillwater Mine and the East Boulder Mine have been aggregated, as both have similar products, processes, customers, distribution methods and economic characteristics.
	The PGM Recycling segment is engaged in the recycling of spent catalyst material to recover the PGMs contained in the material. The Company purchases the majority of catalyst material processed by the PGM Recycling segment from third party suppliers for its own account and sells the recovered metals directly, and it also accepts catalyst material supplied from several third parties on a tolling basis, processing it for a fee and returning the recovered metals to the supplier. The Company allocates costs of the Company's smelting and base metal refining facilities to both the Mine Production segment and to the PGM Recycling segment for internal and segment reporting purposes because these facilities support the PGM extraction requirements of both business segments.
	The Canadian Properties segment consists of the Marathon PGM assets (which consist primarily of the Marathon project mineral property) and the Coldwell Complex exploration mineral properties. The Marathon project mineral property is a large PGM and copper deposit located near the town of Marathon, Ontario, Canada. The Coldwell Complex exploration mineral properties are located adjacent to the Marathon property. In the fourth quarter of 2013, the Company recorded an impairment charge on the Marathon properties and ceased to capitalize future project expenditures incurred in connection with Marathon. Effective December 31, 2013, the Company is no longer reporting proven and probable ore reserves at Marathon or accounting for Marathon as a development-stage project. See "Note 4 - Asset Impairment" of the Company's 2013 Annual Report on Form 10-K for more information.
	The South American Properties segment consists of the Peregrine Metals Ltd. assets. The principal Peregrine property is the Altar project, a copper-gold resource, located in the San Juan province of Argentina. The Altar project is currently in the exploration stage. Financial information for this segment consists of total asset values, general and administrative costs and exploration costs. In the third quarter of 2013, the Company recorded an impairment charge on the Peregrine properties. See "Note 4 - Asset Impairment" of the Company's 2013 Annual Report on Form 10-K for more information.
	The All Other group primarily consists of assets, including investments, revenues, and expenses of various corporate and support functions and, historically, marketing expenditures related to promoting palladium.
	The Company evaluates performance and allocates resources based on income or loss before income taxes.
	The following financial information relates to the Company’s business segments:
	(In thousands)								South American Properties
	Three Months Ended March 31, 2014	Mine		PGM		Canadian						All Other			Total
		Production		Recycling		Properties
	Revenues	$	125,729	$	93,535	$	—		$	—		$	235		$	219,499
	Depletion, depreciation and amortization	$	14,910	$	241	$	—		$	—		$	—		$	15,151
	General and administrative expenses	$	—	$	—	$	1,656		$	200		$	7,748		$	9,604
	Interest income	$	—	$	579	$	2		$	16		$	228		$	825
	Interest expense	$	—	$	—	$	—		$	—		$	5,850		$	5,850
	Income (loss) before income taxes	$	32,827	$	3,168	$	(1,890	)	$	3,185		$	(13,126	)	$	24,164
	Capital expenditures	$	24,861	$	113	$	—		$	—		$	1,159		$	26,133
	Total assets	$	567,505	$	88,931	$	79,856		$	108,839		$	513,719		$	1,358,850
	(In thousands)								South American Properties
	Three Months Ended March 31, 2013	Mine		PGM		Canadian						All Other			Total
		Production		Recycling		Properties
	Revenues	$	128,314	$	122,334	$	—		$	—		$	—		$	250,648
	Depletion, depreciation and amortization	$	15,025	$	258	$	—		$	—		$	—		$	15,283
	General and administrative expenses	$	—	$	—	$	391		$	1,121		$	13,675		$	15,187
	Interest income	$	—	$	817	$	5		$	109		$	269		$	1,200
	Interest expense	$	—	$	—	$	—		$	—		$	6,652		$	6,652
	Income (loss) before income taxes	$	37,536	$	6,031	$	(851	)	$	(1,164	)	$	(22,398	)	$	19,154
	Capital expenditures	$	24,660	$	50	$	2,988		$	94		$	1,614		$	29,406
	Total assets	$	485,640	$	114,656	$	258,032		$	407,235		$	492,902		$	1,758,465

Investments

Investments	3 Months Ended
	Mar. 31, 2014
Investments, Debt and Equity Securities [Abstract]	'
Investments	'
	INVESTMENTS
	The Company classifies the marketable securities in which it invests as available-for-sale securities. These securities are measured at fair market value in the financial statements with unrealized gains or losses recorded in Other comprehensive income in the Company's Consolidated Statements of Comprehensive Income. At the time the securities are sold, or otherwise disposed of, gross realized gains and losses are included in Net income. Gross realized gains and losses are based on the carrying value (cost, net of discount or premiums) of the sold investment. The Company adopted ASU 2013-02 Reporting Amounts Reclassified out of Other Comprehensive Income as of January 1, 2013. The amounts reclassified out of Other comprehensive (loss) income during the three-month periods ended March 31, 2014 and 2013 were insignificant. All of the marketable securities amounts are available to satisfy current obligations.
	The amortized cost, gross unrealized gains, gross unrealized losses, and fair market value of available-for-sale investment securities by major security type and class of security at March 31, 2014, and December 31, 2013, are as follows:
				Investments
	(In thousands)			Amortized cost				Gross unrealized gains		Gross unrealized losses			Fair market value
	2014
		Federal agency notes		$	142,221			$	111	$	—		$	142,332
		Commercial paper		107,711				10		(423		)	107,298
		Mutual funds		403				249		—			652
		Total		$	250,335			$	370	$	(423	)	$	250,282
	2013
		Federal agency notes		$	97,509			$	76	$	—		$	97,585
		Commercial paper		112,063				10		(320		)	111,753
		Mutual funds		359				245		—			604
		Total		$	209,931			$	331	$	(320	)	$	209,942
	The mutual funds included in the investment table above are included in Other noncurrent assets on the Company's Consolidated Balance Sheets.
	The maturities of available-for-sale securities at March 31, 2014, are as follows:
	(In thousands)	Amortized cost				Fair market value
	Federal agency notes
	Due in one year or less	$	54,968			$	55,009
	Due after one year through two years	87,253				87,323
	Total	$	142,221			$	142,332
	Commercial paper
	Due in one year or less	$	85,456			$	85,063
	Due after one year through two years	22,255				22,235
	Total	$	107,711			$	107,298
	The Company has long-term investments in several Canadian junior exploration companies, recorded on the Company's Consolidated Balance Sheets at cost. At March 31, 2014, these long-term investments totaled $1.0 million and are recorded in Other noncurrent assets on the Company's Consolidated Balance Sheets.

Inventories

Inventories	3 Months Ended
	Mar. 31, 2014
Inventory Disclosure [Abstract]	'
Inventories	'
	INVENTORIES
	For purposes of inventory accounting, the market value of inventory is generally deemed equal to the Company’s current cost of replacing the inventory, provided that: (1) the market value of the inventory may not exceed the estimated selling price of such inventory in the ordinary course of business less reasonably predictable costs of completion and disposal, and (2) the market value may not be less than net realizable value reduced by an allowance for a normal profit margin. No adjustments were made to the inventory value in the first three months of 2014 or 2013.
	The costs of mined PGM inventories as of any date are determined based on combined production costs per ounce and include all inventoriable production costs, including direct labor, direct materials, depletion, depreciation, amortization and other overhead costs relating to mining and processing activities incurred as of such date.
	The costs of recycled PGM inventories as of any date are determined based on the acquisition cost of the recycled material and include all inventoriable processing costs, including direct labor, direct materials, depreciation and third party refining costs which relate to the processing activities incurred as of such date.
	Inventories reflected in the accompanying balance sheets consisted of the following:
	(In thousands)	March 31,		December 31, 2013
		2014
	Metals inventory
	Raw ore	$	5,093	$	4,638
	Concentrate and in-process	79,994		67,251
	Finished goods	53,631		60,100
		$	138,718	$	131,989
	Materials and supplies	26,618		26,661
	Total inventory	$	165,336	$	158,650
	The Company also holds in its possession, but does not reflect in inventory, materials it processes on a toll basis for customers and holds for such customers until the tolled material is transported to a third party refiner.

Earnings_Per_Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Earnings Per Share	'
	EARNINGS PER SHARE
	Basic earnings per share attributable to common stockholders is computed by dividing net earnings available to common stockholders by the weighted average number of common shares outstanding during the period. Diluted earnings per share attributable to common stockholders reflects the potential dilution that could occur if the Company’s dilutive outstanding stock options and nonvested shares were exercised or vested and the Company’s convertible debt was converted. For the purposes of calculating earnings per share attributable to common stockholders, reported net income attributable to common stockholders for the first quarter of 2014 and 2013 was adjusted for the interest expense, net of capitalized interest (including amortization expense of deferred debt fees), the related income tax effect and the loss attributable to the noncontrolling interest in the computation of basic and diluted earnings per share attributable to common stockholders. The Company currently has only one class of equity shares outstanding.
	Outstanding options to purchase 81,339 of weighted shares of common stock were excluded from the computation of diluted earnings per share for the three-month period ended March 31, 2013, because the market price at the end of the period was lower than the exercise price, and therefore the effect would have been antidilutive.
	No contingently issuable shares applicable to the Company's nonvested performance restricted stock units were included in the computation of diluted earnings per share for the three-month period ended March 31, 2014.
	Reconciliations showing the computation of basic and diluted shares and the related impact on income for the quarters ended March 31, 2014 and 2013 are shown in the following table:
		Three months ended					Three months ended
		31-Mar-14					31-Mar-13
	(In thousands, except per share amounts)	Income		Weighted	Per Share		Income		Weighted	Per Share
		(Numerator)		Average	Amount		(Numerator)		Average	Amount
				Shares					Shares
				(Denominator)					(Denominator)
	Basic EPS
	Net income attributable to common stockholders	$	19,572	119,608	$	0.16	$	14,583	117,433	$	0.12
	Effect of Dilutive Securities
	Stock options	—		41			—		66
	Nonvested shares	—		7			—		431
	1.875% Convertible debentures, net of tax	—		95			569		5,762
	1.75% Convertible debentures, net of tax	4,104		36,003			3,921		36,003
	Diluted EPS
	Net income attributable to common stockholders and assumed conversions	$	23,676	155,754	$	0.15	$	19,073	159,695	$	0.12

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	FAIR VALUE MEASUREMENTS
	Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants. A three-level fair value hierarchy prioritizes the inputs used to measure fair value. This hierarchy requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The classification of each financial asset or liability within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement. The three levels of inputs used to measure fair value are as follows:
	•	Level 1 - Quoted prices in active markets for identical assets or liabilities.
	•	Level 2 - Observable inputs other than quoted prices included in Level 1 such as quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar assets and liabilities in markets that are not active; or inputs that are observable or can be corroborated by observable market data.
	•	Level 3 - Unobservable inputs supported by little or no market activity and that are significant to the fair value of the assets or liabilities.
	Financial assets and liabilities measured at fair value on a recurring basis at March 31, 2014, and December 31, 2013, consisted of the following:
	(In thousands)		Fair Value Measurements
	At March 31, 2014		Total		Level 1		Level 2		Level 3
	Mutual funds		$	652	$	652	$	—	$	—
	Investments
	Federal agency notes		$	142,332	$	—	$	142,332	$	—
	Commercial paper		$	107,298	$	—	$	107,298	$	—
	(In thousands)		Fair Value Measurements
	At December 31, 2013		Total		Level 1		Level 2		Level 3
	Mutual funds		$	604	$	604	$	—	$	—
	Investments
	Federal agency notes		$	97,585	$	—	$	97,585	$	—
	Commercial paper		$	111,753	$	—	$	111,753	$	—
	The fair value of the mutual funds is based on market prices which are readily available. The fair value of the investments is valued indirectly using observable data, quoted prices for similar assets or liabilities in active markets. Unrealized gains or losses on mutual funds and investments are recorded in Accumulated other comprehensive (loss) income on the Company's Consolidated Balance Sheets.
	Assets and liabilities measured at fair value on a nonrecurring basis at March 31, 2014, and December 31, 2013, consisted of the following:
	(In thousands)		Fair Value Measurements
	At March 31, 2014		Total		Level 1		Level 2		Level 3
	1.875% Convertible debentures		$	2,245	$	—	$	2,245	$	—
	1.75% Convertible debentures		$	360,021	$	—	$	360,021	$	—
	Exempt facility revenue bonds		$	31,776	$	—	$	—	$	31,776
	(In thousands)		Fair Value Measurements
	At December 31, 2013		Total		Level 1		Level 2		Level 3
	Marathon mineral properties and property, plant and equipment		$	57,272	$	—	$	—	$	57,272
	1.875% Convertible debentures		$	2,245	$	—	$	2,245	$	—
	1.75% Convertible debentures		$	308,574	$	—	$	308,574	$	—
	Exempt facility industrial revenue bonds		$	30,050	$	—	$	—	$	30,050
	Long-term investments		$	1,021	$	1,021	$	—	$	—
	The Company used implicit interest rates of comparable unsecured obligations to calculate the fair value of the Company’s $30 million in principal amount of 8.0% Series 2000 exempt facility revenue bonds at March 31, 2014, and December 31, 2013. The Company used its current trading data to determine the fair value of each of its convertible debentures, the $2.2 million of outstanding 1.875% debentures and the $396.75 million of outstanding 1.75% debentures at March 31, 2014, and December 31, 2013. The fair value of the Company's long-term investments in certain Canadian junior exploration companies at December 31, 2013, is based on market prices which are readily available. The fair market value of the Marathon mineral property as of December 31, 2013, was based on comparable transactions for similar undeveloped mineral properties and market multiples for similar projects. The fair market value of the Company's Altar mineral property was remeasured at the end of the third quarter of 2013 based on Level 3 inputs such as comparable transactions for similar undeveloped mineral properties and market multiples for similar projects.

Related_Parties

Related Parties	3 Months Ended
	Mar. 31, 2014
Related Party Transactions [Abstract]	'
Related Parties	'
	RELATED PARTIES
	Mitsubishi owns a 25% interest in the Company's previously wholly-owned subsidiary, SCI, which owns the Marathon PGM-copper project and related properties located in northern Ontario, Canada. The Company made PGM sales of $48.0 million and $65.8 million to Mitsubishi in the three-month periods ended March 31, 2014 and 2013, respectively.

Sales_Tables

Sales (Tables)	3 Months Ended
	Mar. 31, 2014
Sales Revenue, Goods, Net [Abstract]	'
Percentage Of Total Revenues From Significant Customers	'
	Total sales to significant customers as a percentage of total revenues for the three-month periods ended March 31, 2014 and 2013 were as follows:
		Three Months Ended March 31,
		2014(1)		2013(1)
	Customer A	33	%	14	%
	Customer B	22	%	26	%
	Customer C	11	%	—
	Customer D	—		16	%
	Customer E	—		16	%
		66	%	72	%
	(1) The “—” symbol represents less than 10% of total revenues.

Derivative_Instruments_Tables

Derivative Instruments (Tables)	3 Months Ended
	Mar. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Schedule of Company's outstanding commodity derivatives	'
	The following is a summary of the Company's commodity derivatives in place as of March 31, 2014:
	PGM Recycling:
	Fixed Forwards	Platinum			Palladium			Rhodium
	Settlement Period	Ounces	Average		Ounces	Average		Ounces	Average
			Price			Price			Price
	Second Quarter 2014	30,523	$	1,424	51,033	$	743	7,018	$	1,014
	Third Quarter 2014	5,464	$	1,449	5,965	$	774	2,158	$	1,075

ShareBased_Compensation_Tables

Share-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Changes In The Company's Nonvested Shares	'
	The following table summarizes the status of and changes in the Company’s nonvested shares during the first three months of 2014:
		Nonvested Shares		Weighted-Average Grant-Date Fair Value
	Nonvested shares at January 1, 2014	31,057		$	11.55
	Granted	563,375		14.66
	Vested	—		—
	Forfeited	(200	)	11.81
	Nonvested shares at March 31, 2014	594,232		$	14.5
Compensation Expense of Nonvested Shares	'
	The following table presents the compensation expense of the nonvested shares outstanding at March 31, 2014 to be recognized over the remaining vesting periods:
	(In millions)	Compensation Expense
	Remaining 2014	$	2.3
	2015	2.9
	2016	2.9
	2017	0.3
	Total	$	8.4

Debt_and_Capital_Lease_Obligat1

Debt and Capital Lease Obligations (Tables)	3 Months Ended
	Mar. 31, 2014
Debt Disclosure [Abstract]	'
Schedule of Future Minimum Lease Payments for Capital Leases	'
	The following is a schedule, by year, of the future minimum lease payments for the capital lease together with the present value of the net minimum lease payments:
	(In thousands)
	Remaining 2014	$	1,625
	2015	2,168
	2016	590
	Total minimum lease payments	$	4,383
	Less interest at rates ranging from 5.21% to 5.46% (before-tax)	259
	Net minimum lease payments	$	4,124
	Less current portion	1,984
	Total long-term capital lease obligation	$	2,140

Mineral_Properties_and_Mine_De1

Mineral Properties and Mine Development (Tables)	3 Months Ended
	Mar. 31, 2014
Extractive Industries [Abstract]	'
Schedule of Mineral Properties and Mine Development	'
	Mineral properties and mine development reflected in the accompanying balance sheets consisted of the following:
	(In thousands)	March 31,			December 31, 2013
		2014
	Mineral Properties:
	Montana, United States of America
	Stillwater Mine	$	1,950		$	1,950
	Ontario, Canada
	Marathon properties	50,915			50,915
	Coldwell Complex property	4,417			4,417
	San Juan, Argentina
	Altar property	101,970			101,970
	Mine Development:
	Montana, United States of America
	Stillwater Mine	$	549,940		$	532,480
	East Boulder Mine	183,697			179,263
		$	892,889		$	870,995
	Less accumulated depletion and amortization	(375,961		)	(365,397		)
	Total mineral properties and mine development	$	516,928		$	505,598

Property_Plant_and_Equipment_T

Property, Plant and Equipment (Tables)	3 Months Ended
	Mar. 31, 2014
Property, Plant and Equipment [Abstract]	'
Schedule of Property, Plant and Equipment	'
	Property, plant and equipment reflected in the accompanying balance sheets consisted of the following:
	(In thousands)	March 31,			December 31, 2013
		2014
	Machinery and equipment	$	141,662		$	138,351
	Buildings and structural components	166,404			160,076
	Land	8,592			8,592
	Construction-in-progress:
	Stillwater Mine	1,541			5,818
	East Boulder Mine	904			1,057
	Marathon	402			402
	Processing facilities and other	2,886			5,841
		$	322,391		$	320,137
	Less accumulated depreciation	(200,970		)	(195,406		)
	Total property, plant, and equipment	$	121,421		$	124,731
Schedule Capital Expenditures	'
	The Company's capital outlay for the three-month periods ended March 31, 2014 and 2013, was as follows:
	(In thousands)	March 31,			March 31
		2014			2013
	Stillwater Mine	$	18,485		$	18,522
	East Boulder Mine	6,375			6,138
	Marathon project	—			2,988
	Altar project	—			94
	Other	1,273			1,664
	Total capital outlay	$	26,133		$	29,406

Segment_Information_Tables

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Financial Information Related To The Company's Business Segments	'
	The following financial information relates to the Company’s business segments:
	(In thousands)								South American Properties
	Three Months Ended March 31, 2014	Mine		PGM		Canadian						All Other			Total
		Production		Recycling		Properties
	Revenues	$	125,729	$	93,535	$	—		$	—		$	235		$	219,499
	Depletion, depreciation and amortization	$	14,910	$	241	$	—		$	—		$	—		$	15,151
	General and administrative expenses	$	—	$	—	$	1,656		$	200		$	7,748		$	9,604
	Interest income	$	—	$	579	$	2		$	16		$	228		$	825
	Interest expense	$	—	$	—	$	—		$	—		$	5,850		$	5,850
	Income (loss) before income taxes	$	32,827	$	3,168	$	(1,890	)	$	3,185		$	(13,126	)	$	24,164
	Capital expenditures	$	24,861	$	113	$	—		$	—		$	1,159		$	26,133
	Total assets	$	567,505	$	88,931	$	79,856		$	108,839		$	513,719		$	1,358,850
	(In thousands)								South American Properties
	Three Months Ended March 31, 2013	Mine		PGM		Canadian						All Other			Total
		Production		Recycling		Properties
	Revenues	$	128,314	$	122,334	$	—		$	—		$	—		$	250,648
	Depletion, depreciation and amortization	$	15,025	$	258	$	—		$	—		$	—		$	15,283
	General and administrative expenses	$	—	$	—	$	391		$	1,121		$	13,675		$	15,187
	Interest income	$	—	$	817	$	5		$	109		$	269		$	1,200
	Interest expense	$	—	$	—	$	—		$	—		$	6,652		$	6,652
	Income (loss) before income taxes	$	37,536	$	6,031	$	(851	)	$	(1,164	)	$	(22,398	)	$	19,154
	Capital expenditures	$	24,660	$	50	$	2,988		$	94		$	1,614		$	29,406
	Total assets	$	485,640	$	114,656	$	258,032		$	407,235		$	492,902		$	1,758,465

Investments_Tables

Investments (Tables)	3 Months Ended
	Mar. 31, 2014
Investments, Debt and Equity Securities [Abstract]	'
Schedule of Available-for-sale Securities	'
	The amortized cost, gross unrealized gains, gross unrealized losses, and fair market value of available-for-sale investment securities by major security type and class of security at March 31, 2014, and December 31, 2013, are as follows:
				Investments
	(In thousands)			Amortized cost				Gross unrealized gains		Gross unrealized losses			Fair market value
	2014
		Federal agency notes		$	142,221			$	111	$	—		$	142,332
		Commercial paper		107,711				10		(423		)	107,298
		Mutual funds		403				249		—			652
		Total		$	250,335			$	370	$	(423	)	$	250,282
	2013
		Federal agency notes		$	97,509			$	76	$	—		$	97,585
		Commercial paper		112,063				10		(320		)	111,753
		Mutual funds		359				245		—			604
		Total		$	209,931			$	331	$	(320	)	$	209,942
Schedule of Maturities of Available-for-sale Securities	'
	The maturities of available-for-sale securities at March 31, 2014, are as follows:
	(In thousands)	Amortized cost				Fair market value
	Federal agency notes
	Due in one year or less	$	54,968			$	55,009
	Due after one year through two years	87,253				87,323
	Total	$	142,221			$	142,332
	Commercial paper
	Due in one year or less	$	85,456			$	85,063
	Due after one year through two years	22,255				22,235
	Total	$	107,711			$	107,298

Inventories_Tables

Inventories (Tables)	3 Months Ended
	Mar. 31, 2014
Inventory Disclosure [Abstract]	'
Components Of Inventories	'
	Inventories reflected in the accompanying balance sheets consisted of the following:
	(In thousands)	March 31,		December 31, 2013
		2014
	Metals inventory
	Raw ore	$	5,093	$	4,638
	Concentrate and in-process	79,994		67,251
	Finished goods	53,631		60,100
		$	138,718	$	131,989
	Materials and supplies	26,618		26,661
	Total inventory	$	165,336	$	158,650

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Reconciliation of Basic and Diluted Earnings Per Share	'
		Three months ended					Three months ended
		31-Mar-14					31-Mar-13
	(In thousands, except per share amounts)	Income		Weighted	Per Share		Income		Weighted	Per Share
		(Numerator)		Average	Amount		(Numerator)		Average	Amount
				Shares					Shares
				(Denominator)					(Denominator)
	Basic EPS
	Net income attributable to common stockholders	$	19,572	119,608	$	0.16	$	14,583	117,433	$	0.12
	Effect of Dilutive Securities
	Stock options	—		41			—		66
	Nonvested shares	—		7			—		431
	1.875% Convertible debentures, net of tax	—		95			569		5,762
	1.75% Convertible debentures, net of tax	4,104		36,003			3,921		36,003
	Diluted EPS
	Net income attributable to common stockholders and assumed conversions	$	23,676	155,754	$	0.15	$	19,073	159,695	$	0.12

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Financial Assets And Liabilities Measured At Fair Value On A Recurring Basis	'
	Financial assets and liabilities measured at fair value on a recurring basis at March 31, 2014, and December 31, 2013, consisted of the following:
	(In thousands)	Fair Value Measurements
	At March 31, 2014	Total		Level 1		Level 2		Level 3
	Mutual funds	$	652	$	652	$	—	$	—
	Investments
	Federal agency notes	$	142,332	$	—	$	142,332	$	—
	Commercial paper	$	107,298	$	—	$	107,298	$	—
	(In thousands)	Fair Value Measurements
	At December 31, 2013	Total		Level 1		Level 2		Level 3
	Mutual funds	$	604	$	604	$	—	$	—
	Investments
	Federal agency notes	$	97,585	$	—	$	97,585	$	—
	Commercial paper	$	111,753	$	—	$	111,753	$	—
Financial Assets And Liabilities Measured At Fair Value On A Nonrecurring Basis	'
	ssets and liabilities measured at fair value on a nonrecurring basis at March 31, 2014, and December 31, 2013, consisted of the following:
	(In thousands)	Fair Value Measurements
	At March 31, 2014	Total		Level 1		Level 2		Level 3
	1.875% Convertible debentures	$	2,245	$	—	$	2,245	$	—
	1.75% Convertible debentures	$	360,021	$	—	$	360,021	$	—
	Exempt facility revenue bonds	$	31,776	$	—	$	—	$	31,776
	(In thousands)	Fair Value Measurements
	At December 31, 2013	Total		Level 1		Level 2		Level 3
	Marathon mineral properties and property, plant and equipment	$	57,272	$	—	$	—	$	57,272
	1.875% Convertible debentures	$	2,245	$	—	$	2,245	$	—
	1.75% Convertible debentures	$	308,574	$	—	$	308,574	$	—
	Exempt facility industrial revenue bonds	$	30,050	$	—	$	—	$	30,050
	Long-term investments	$	1,021	$	1,021	$	—	$	—

General_Details

General (Details) (Subsequent Event [Member], USD $)	1 Months Ended
In Millions, unless otherwise specified	1-May-14
Subsequent Event [Member]	'
Subsequent Event [Line Items]	'
Estimated restructuring costs to be recognized	$4.30

Sales_Narrative_Details

Sales (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Sales Revenue, Goods, Net [Abstract]	'	'
Platinum group metals purity percentage	99.95%	'
Rhodium purity percentage	99.90%	'
Revenues from by-product sales	$6,700,000	$7,500,000
Market-based platinum supply agreement, term	'1 year	'
Revenue from inventory purchased from a wholly-owned subsidiary	$235,000	$0

Sales_Percentage_Of_Total_Reve

Sales (Percentage Of Total Revenues From Significant Customers) (Details) (Sales Revenue, Goods, Net [Member], Customer Concentration Risk [Member])	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Revenue, Major Customer [Line Items]	'		'
Major customer, percentage of total revenues	66.00%	[1]	72.00%	[1]
Customer A	'		'
Revenue, Major Customer [Line Items]	'		'
Major customer, percentage of total revenues	33.00%	[1]	14.00%	[1]
Customer B	'		'
Revenue, Major Customer [Line Items]	'		'
Major customer, percentage of total revenues	22.00%	[1]	26.00%	[1]
Customer C	'		'
Revenue, Major Customer [Line Items]	'		'
Major customer, percentage of total revenues	11.00%	[1]	0.00%	[1]
Customer D	'		'
Revenue, Major Customer [Line Items]	'		'
Major customer, percentage of total revenues	0.00%	[1]	16.00%	[1]
Customer E	'		'
Revenue, Major Customer [Line Items]	'		'
Major customer, percentage of total revenues	0.00%	[1]	16.00%	[1]
[1]	The “—” symbol represents less than 10% of total revenues

Asset_Impairment_Details

Asset Impairment (Details) (USD $)	3 Months Ended
	Sep. 30, 2013	Dec. 31, 2013
	Altar Property [Member]	Marathon Property [Member]
	San Juan, Argentina [Member]
Impaired Long-Lived Assets Held and Used [Line Items]	'	'
Impairment charge	$290,400,000	$171,400,000
Marathon mineral properties and property, plant and equipment	102,000,000	'
Mineral Properties and Mine Development, and Property, Plant and Equipment, Fair Value Disclosure	'	$57,200,000

Noncontrolling_Interest_Detail

Noncontrolling Interest (Details) (USD $)	3 Months Ended		12 Months Ended		12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2014	Dec. 31, 2012
			Additional Paid-in Capital [Member]	Noncontrolling Interest [Member]	Stillwater Canada Inc [Member]
Noncontrolling Interest [Line Items]	'	'	'	'	'
Noncontrolling interest, ownership percentage by noncontrolling owners	'	'	'	'	25.00%
Cost of acquired entity, cash paid by third party	'	'	'	'	$81,250,000
Contribution, initial cash call, amount paid by third party	'	'	'	'	13,600,000
Maximum PGM production purchase percentage	100.00%	'	'	'	'
Issuance of noncontrolling interest	'	'	42,500,000	'	'
Expenses incurred for issuance of noncontrolling interest	'	'	1,100,000	'	'
Noncontrolling interest	$19,361,000	$19,894,000	'	$19,400,000	'

Derivative_Instruments_Company

Derivative Instruments (Company's Outstanding Commodity Derivatives) (Details)	3 Months Ended
	Mar. 31, 2014
	oz
Second Quarter 2014 | Platinum [Member]	'
Derivative [Line Items]	'
Ounces	30,523
Average Price	1,424
Second Quarter 2014 | Palladium [Member]	'
Derivative [Line Items]	'
Ounces	51,033
Average Price	743
Second Quarter 2014 | Rhodium [Member]	'
Derivative [Line Items]	'
Ounces	7,018
Average Price	1,014
Third Quarter 2014 | Platinum [Member]	'
Derivative [Line Items]	'
Ounces	5,464
Average Price	1,449
Third Quarter 2014 | Palladium [Member]	'
Derivative [Line Items]	'
Ounces	5,965
Average Price	774
Third Quarter 2014 | Rhodium [Member]	'
Derivative [Line Items]	'
Ounces	2,158
Average Price	1,075

ShareBased_Compensation_Narrat

Share-Based Compensation (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Number of stock plans	2	'	'
Number of terminated stock plans	2	'	'
Vesting period	'3 years	'	'
Award expiration period	'10 years	'	'
Cash received from stock options exercised	$500,000	'	'
Stillwater Mining Company [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Number of shares authorized for issuance	16,400,000	'	'
Maximum [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Cash received from stock options exercised	'	100,000	'
Restricted Stock Units (RSUs) [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Share-based compensation expense	200,000	1,700,000	'
Nonvested shares	594,232	'	31,057
Stock Options [Member] | General and administrative expense	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Share-based compensation expense	$0	$11,000	'
Time-Based Restricted Stock Units [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Nonvested shares	370,820	'	'
Performance-Based Restricted Stock Units [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Nonvested shares	223,412	'	'
2004 and 2012 Plans Combined [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Shares available and reserved for grant	4,400,000	'	'
2012 Equity Incentive Plan [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Number of shares authorized for issuance	5,000,000	'	'
2004 Equity Incentive Plan [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Number of shares authorized for issuance	5,200,000	'	'
General Employee Plan [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Number of shares authorized for issuance	1,400,000	'	'
1994 Incentive Plan [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Number of shares authorized for issuance	4,800,000	'	'

ShareBased_Compensation_Change

Share-Based Compensation (Changes In The Company's Nonvested Shares) (Details) (Restricted Stock Units (RSUs) [Member], USD $)	3 Months Ended
	Mar. 31, 2014
Restricted Stock Units (RSUs) [Member]	'
Nonvested Shares	'
Nonvested Shares, Beginning Balance	31,057
Nonvested Shares, Granted	563,375
Nonvested Shares, Vested	0
Nonvested Shares, Forfeited	-200
Nonvested Shares, Ending Balance	594,232
Weighted-Average Grant-Date Fair Value	'
Nonvested shares, Weighted-Average Grant-Date Fair Value, Beginning Balance (in usd per share)	$11.55
Nonvested shares, Weighted-Average Grant-Date Fair Value, Granted (in usd per share)	$14.66
Nonvested shares, Weighted-Average Grant-Date Fair Value, Vested (in usd per share)	$0
Nonvested shares, Weighted-Average Grant-Date Fair Value, Forfeited (in usd per share)	$11.81
Nonvested shares, Weighted-Average Grant-Date Fair Value, Ending Balance (in usd per share)	$14.50

ShareBased_Compensation_Compen

Share-Based Compensation Compensation Expense of Nonvested Shares (Details) (USD $)	Mar. 31, 2014
In Millions, unless otherwise specified
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Remaining 2014	$0
2015	0
2016	0
2017	0
Total	$0

Income_Taxes_Details

Income Taxes (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Income Tax Contingency [Line Items]	'	'
Alternative minimum tax credit carryforwards	$30,500,000	'
General business credits	1,200,000	'
State tax net operating loss carryforwards	2,400,000	'
Foreign net operating loss carryforward	56,100,000	'
Income tax provision	-5,125,000	-4,850,000
Interest and penalties accrued	2,100,000	'
Cash paid for income taxes	1,200,000	2,400,000
Year 2014 [Member]	'	'
Income Tax Contingency [Line Items]	'	'
Foreign net operating loss carryforward	20,100,000	'
Year 2024 to 2034 [Member]	'	'
Income Tax Contingency [Line Items]	'	'
Foreign net operating loss carryforward	26,400,000	'
Norilsk Nickel Change in Control [Member]	'	'
Income Tax Contingency [Line Items]	'	'
Net operating loss carryforwards	89,400,000	'
Annual limit on usage of net operating loss carryforwards	10,200,000	'
Federal [Member]	'	'
Income Tax Contingency [Line Items]	'	'
Net operating loss carryforwards	125,200,000	'
Foreign Tax Authority [Member]	'	'
Income Tax Contingency [Line Items]	'	'
Foreign net operating loss carryforward, not subject to expiration	9,600,000	'
State and Local [Member]	'	'
Income Tax Contingency [Line Items]	'	'
Tax provision impact of unpaid tax	$1,800,000	'

Debt_and_Capital_Lease_Obligat2

Debt and Capital Lease Obligations (Narrative) (Details) (USD $)

3 Months Ended

3 Months Ended

1 Months Ended

3 Months Ended

1 Months Ended

3 Months Ended

3 Months Ended

12 Months Ended

1 Months Ended

3 Months Ended

Mar. 31, 2014

Mar. 31, 2013

Dec. 31, 2013

Mar. 31, 2014

Oct. 31, 2012

Oct. 31, 2009

Mar. 31, 2014

Mar. 31, 2013

Dec. 31, 2013

Dec. 31, 2009

Mar. 31, 2008

Oct. 31, 2012

Mar. 31, 2014

Mar. 31, 2013

Dec. 31, 2013

Mar. 31, 2014

Mar. 31, 2013

Dec. 31, 2000

Dec. 31, 2013

Jan. 31, 2012

Dec. 31, 2011

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2013

Maximum [Member]

1.875% Convertible debentures [Member]

1.875% Convertible debentures [Member]

1.875% Convertible debentures [Member]

1.875% Convertible debentures [Member]

1.875% Convertible debentures [Member]

1.875% Convertible debentures [Member]

1.875% Convertible debentures [Member]

1.75% Convertible Debentures [Member]

1.75% Convertible Debentures [Member]

1.75% Convertible Debentures [Member]

1.75% Convertible Debentures [Member]

8% Series 2000 [Member]

8% Series 2000 [Member]

8% Series 2000 [Member]

8% Series 2000 [Member]

Credit Agreement [Member]

Credit Agreement [Member]

Credit Agreement [Member]

Credit Agreement [Member]

Credit Agreement [Member]

Credit Agreement [Member]

Credit Agreement [Member]

Minimum [Member]

Maximum [Member]

Maximum [Member]

Debt Instruments [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt, principal amount

'

'

'

'

'

'

'

'

'

'

$181,500,000

$396,750,000

$396,750,000

'

$396,750,000

$30,000,000

'

'

$30,000,000

'

'

'

'

'

'

'

Debt, maturity date

'

'

'

'

'

'

15-Mar-28

'

'

'

'

'

'

'

'

1-Jul-20

'

'

'

'

'

'

'

'

'

'

Stated interest rate

1.75%

'

'

'

'

'

1.88%

'

1.88%

'

'

'

1.75%

'

1.75%

8.00%

'

'

8.00%

'

'

'

'

'

'

'

Common stock issuable on conversion of debt per $1,000 (in shares)

'

'

'

'

'

'

42.5351

'

'

'

'

'

60.4961

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt conversion price (in usd per share)

'

'

'

'

'

'

$23.51

'

'

'

'

'

$16.53

'

'

'

'

'

'

'

'

'

'

'

'

'

Convertible debentures exchanged for shares, value

'

'

'

'

'

15,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Convertible debentures exchanged for shares, shares

'

'

'

'

'

1,840,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Senior Notes

'

'

'

'

'

'

'

'

'

166,500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Repayments of convertible debentures

'

'

'

'

164,300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Convertible debentures

'

'

'

'

'

'

2,200,000

'

2,200,000

'

'

'

278,200,000

'

274,000,000

'

'

'

'

'

'

'

'

'

'

'

Amortization expense related to issuance costs

364,000

557,000

'

'

'

'

0

200,000

'

'

'

'

300,000

300,000

'

'

'

'

'

'

'

'

'

'

100,000

100,000

Interest expense

'

'

'

'

'

'

10,500

700,000

'

'

'

'

5,900,000

5,600,000

'

'

'

'

'

'

'

'

'

'

'

'

Cash paid for interest

'

100,000

'

100,000

'

'

21,000

1,600,000

'

'

'

'

0

0

'

0

0

'

'

'

'

'

'

'

'

'

Embedded conversion feature, warrant, conversion ratio

'

'

'

'

'

'

'

'

'

'

'

'

30.2481

'

'

'

'

'

'

'

'

'

'

'

'

'

Embedded conversion feature, warrant, conversion price (in usd per share)

'

'

'

'

'

'

'

'

'

'

'

'

$16.53

'

'

'

'

'

'

'

'

'

'

'

'

'

Adjustments to equity, component of convertible debt treated as additional debt discount

'

'

'

'

'

'

'

'

'

'

'

141,600,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt and equity issuance costs

'

'

'

'

'

'

'

'

'

'

'

12,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt and equity issuance costs amortization period

'

'

'

'

'

'

'

'

'

'

'

'

'7 years

'

'

'

'

'

'

'

'

'

'

'

'

'

Effective interest rate

'

'

'

'

'

'

'

'

'

'

'

'

8.50%

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term debt, balance outstanding

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

29,600,000

'

'

29,600,000

'

'

'

'

'

'

'

Unamortized discount

'

'

'

'

'

'

'

'

'

'

'

'

118,600,000

'

122,800,000

400,000

'

'

400,000

'

'

'

'

'

'

'

Credit agreement

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

125,000,000

100,000,000

'

'

'

'

'

Debt issuance costs

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

200,000

1,100,000

'

'

'

'

'

Borrowing base comprised eligible accounts receivable

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

85.00%

'

'

'

'

Borrowing base comprised eligible accounts inventories

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

70.00%

'

'

'

'

Percentage of total borrowing capacity remaining when covenant takes effect

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

30.00%

'

Letter of credit sub-facility

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

60,000,000

'

'

'

'

Basis spread over LIBOR

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2.25%

2.75%

'

Unused line fee on committed but unutilized commitments

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0.38%

0.50%

'

Undrawn letters of credit issued as collateral for sureties

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

17,500,000

'

'

'

'

Asset-backed revolving credit facility fees recognized

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

300,000

300,000

'

'

'

Capital Lease Obligation

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Payments on capital lease obligations

500,000

500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash paid for interest

'

100,000

'

100,000

'

'

21,000

1,600,000

'

'

'

'

0

0

'

0

0

'

'

'

'

'

'

'

'

'

Capital lease obligations

4,100,000

'

4,600,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Capitalized Interest

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Capitalized interest

1,100,000

800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Proceeds from Issuance of Long-term Debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$28,700,000

'

'

'

'

'

'

'

'

Debt, Weighted Average Interest Rate

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

8.57%

'

'

'

'

'

'

'

'

'

'

Debt_and_Capital_Lease_Obligat3

Debt and Capital Lease Obligation (Schedule of Future Minimum Lease Payments for Capital Leases) (Details) (USD $)	Mar. 31, 2014
In Thousands, unless otherwise specified
Present Value of Net Minimum Lease Payments	'
Remaining 2014	$1,625
2015	2,168
2016	590
Total minimum lease payments	4,383
Less interest at rates ranging from 5.21% to 5.46% (before-tax)	259
Net minimum lease payments	4,124
Less current portion	1,984
Total long-term capital lease obligation	$2,140
Minimum [Member]	'
Present Value of Net Minimum Lease Payments	'
Capital lease, interest rate	5.21%
Maximum [Member]	'
Present Value of Net Minimum Lease Payments	'
Capital lease, interest rate	5.46%

Mineral_Properties_and_Mine_De2

Mineral Properties and Mine Development (Schedule of Mineral Properties) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Mining Properties, Mineral Rights and Mine Development [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Mineral properties and mine development, gross	$892,889	$870,995
Less accumulated depletion and amortization	-375,961	-365,397
Total mineral properties and mine development	516,928	505,598
Montana, United States of America [Member] | Mining Properties and Mineral Rights [Member] | Stillwater Mine [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Mineral properties and mine development, gross	1,950	1,950
Montana, United States of America [Member] | Mine Development [Member] | Stillwater Mine [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Mineral properties and mine development, gross	549,940	532,480
Montana, United States of America [Member] | Mine Development [Member] | East Boulder Mine [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Mineral properties and mine development, gross	183,697	179,263
Ontario, Canada [Member] | Mining Properties and Mineral Rights [Member] | Marathon Property [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Mineral properties and mine development, gross	50,915	50,915
Ontario, Canada [Member] | Mining Properties and Mineral Rights [Member] | Coldwell Complex Property [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Mineral properties and mine development, gross	4,417	4,417
San Juan, Argentina [Member] | Mining Properties and Mineral Rights [Member] | Altar Property [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Mineral properties and mine development, gross	$101,970	$101,970

Property_Plant_and_Equipment_S

Property, Plant and Equipment (Schedule of Property, Plant and Equipment) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Property, Plant and Equipment [Line Items]	'	'	'
Property, plant, and equipment, gross	$322,391	'	$320,137
Less accumulated depreciation	-200,970	'	-195,406
Total property, plant, and equipment	121,421	'	124,731
Total capital outlay	26,133	29,406	'
Stillwater Mine [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Total capital outlay	18,485	18,522	'
East Boulder Mine [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Total capital outlay	6,375	6,138	'
Marathon Property [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Total capital outlay	0	2,988	'
Altar Property [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Total capital outlay	0	94	'
Other Mine [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Total capital outlay	1,273	1,664	'
Machinery and equipment	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Property, plant, and equipment, gross	141,662	'	138,351
Buildings and structural components	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Property, plant, and equipment, gross	166,404	'	160,076
Land	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Property, plant, and equipment, gross	8,592	'	8,592
Construction-in progress | Stillwater Mine [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Property, plant, and equipment, gross	1,541	'	5,818
Construction-in progress | East Boulder Mine [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Property, plant, and equipment, gross	904	'	1,057
Construction-in progress | Processing Facilities and Other [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Property, plant, and equipment, gross	2,886	'	5,841
Construction-in progress | Marathon Property [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Property, plant, and equipment, gross	$402	'	$402

Segment_Information_Narrative_

Segment Information (Narrative) (Details)	3 Months Ended
	Mar. 31, 2014
	Business_Component
Mine Production [Member]	'
Segment Reporting Information [Line Items]	'
Number of business components	2
Stillwater Mining Company [Member]	'
Segment Reporting Information [Line Items]	'
Number of business segments	5

Segment_Information_Financial_

Segment Information (Financial Information Related To The Company's Business Segments) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Segment Reporting Information [Line Items]	'	'	'
Revenues	$219,499	$250,648	'
Depletion, depreciation and amortization	15,151	15,283	'
General and administrative expenses	9,604	15,187	'
Interest income	825	1,200	'
Interest expense	5,850	6,652	'
Income (loss) before income taxes	24,164	19,154	'
Capital expenditures	26,133	29,406	'
Total assets	1,358,850	1,758,465	1,346,680
Mine Production [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	125,729	128,314	'
Depletion, depreciation and amortization	14,910	15,025	'
General and administrative expenses	0	0	'
Interest income	0	0	'
Interest expense	0	0	'
Income (loss) before income taxes	32,827	37,536	'
Capital expenditures	24,861	24,660	'
Total assets	567,505	485,640	'
PGM Recycling [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	93,535	122,334	'
Depletion, depreciation and amortization	241	258	'
General and administrative expenses	0	0	'
Interest income	579	817	'
Interest expense	0	0	'
Income (loss) before income taxes	3,168	6,031	'
Capital expenditures	113	50	'
Total assets	88,931	114,656	'
Canadian Properties [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	0	0	'
Depletion, depreciation and amortization	0	0	'
General and administrative expenses	1,656	391	'
Interest income	2	5	'
Interest expense	0	0	'
Income (loss) before income taxes	-1,890	-851	'
Capital expenditures	0	2,988	'
Total assets	79,856	258,032	'
South American Properties [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	0	0	'
Depletion, depreciation and amortization	0	0	'
General and administrative expenses	200	1,121	'
Interest income	16	109	'
Interest expense	0	0	'
Income (loss) before income taxes	3,185	-1,164	'
Capital expenditures	0	94	'
Total assets	108,839	407,235	'
All Other [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	235	0	'
Depletion, depreciation and amortization	0	0	'
General and administrative expenses	7,748	13,675	'
Interest income	228	269	'
Interest expense	5,850	6,652	'
Income (loss) before income taxes	-13,126	-22,398	'
Capital expenditures	1,159	1,614	'
Total assets	$513,719	$492,902	'

Investments_Narrative_Details

Investments (Narrative) (Details) (Other Noncurrent Assets [Member], USD $)	Mar. 31, 2014
In Millions, unless otherwise specified
Other Noncurrent Assets [Member]	'
Schedule of Available-for-sale Securities [Line Items]	'
Long-term investments	$1

Investments_Schedule_of_Availa

Investments (Schedule of Available-for-sale Securities) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized cost	$250,335	$209,931
Gross unrealized gains	370	331
Gross unrealized losses	-423	-320
Fair market value	250,282	209,942
Federal agency notes [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized cost	142,221	97,509
Gross unrealized gains	111	76
Gross unrealized losses	0	0
Fair market value	142,332	97,585
Commercial paper [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized cost	107,711	112,063
Gross unrealized gains	10	10
Gross unrealized losses	-423	-320
Fair market value	107,298	111,753
Mutual funds [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized cost	403	359
Gross unrealized gains	249	245
Gross unrealized losses	0	0
Fair market value	$652	$604

Investments_Schedule_of_Maturi

Investments (Schedule of Maturities of Available-for-sale Securities) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized cost	$250,335	$209,931
Fair market value	250,282	209,942
Federal agency notes [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized cost, due in one year or less	54,968	'
Fair market value, due in one year or less	55,009	'
Amortized cost, due after year one through two years	87,253	'
Fair market value, due after year one through two years	87,323	'
Amortized cost	142,221	97,509
Fair market value	142,332	97,585
Commercial paper [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized cost, due in one year or less	85,456	'
Fair market value, due in one year or less	85,063	'
Amortized cost, due after year one through two years	22,255	'
Fair market value, due after year one through two years	22,235	'
Amortized cost	107,711	112,063
Fair market value	$107,298	$111,753

Inventories_Components_Of_Inve

Inventories (Components Of Inventories) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Metals inventory	'	'
Raw ore	$5,093	$4,638
Concentrate and in-process	79,994	67,251
Finished goods	53,631	60,100
Metals inventory	138,718	131,989
Materials and supplies	26,618	26,661
Total inventory	$165,336	$158,650

Narrative_Details

(Narrative) (Details) (Stock Options, Market Price Less Than Exercise Price [Member])	3 Months Ended
	Mar. 31, 2013
Stock Options, Market Price Less Than Exercise Price [Member]	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'
Outstanding options excluded from computation of diluted earnings per share	81,339

Earnings_Per_Share_Reconciliat

Earnings Per Share (Reconciliation of Basic and Diluted Earnings Per Share) (Details) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Basic EPS	'	'	'
Net income attributable to common stockholders	$19,572	$14,583	'
Basic EPS, Weighted Average Shares (Denominator) (in shares)	119,608	117,433	'
Basic earnings per share attributable to common stockholders (in usd per share)	$0.16	$0.12	'
Effect of Dilutive Securities	'	'	'
Effect of stock options (in shares)	41	66	'
Effect of nonvested shares (in shares)	7	431	'
Diluted EPS	'	'	'
Net income attributable to common stockholders and assumed conversions	23,676	19,073	'
Diluted EPS, Weighted Average Shares (Denominator) (in shares)	155,754	159,695	'
Diluted earnings per share attributable to common stockholders (in usd per share)	$0.15	$0.12	'
Stated interest rate	1.75%	'	'
1.875% Convertible debentures [Member]	'	'	'
Effect of Dilutive Securities	'	'	'
Effect of convertible debentures, net of tax	0	569	'
Effect of convertible debentures (in shares)	95	5,762	'
Diluted EPS	'	'	'
Stated interest rate	1.88%	'	1.88%
1.75% Convertible Debentures [Member]	'	'	'
Effect of Dilutive Securities	'	'	'
Effect of convertible debentures, net of tax	$4,104	$3,921	'
Effect of convertible debentures (in shares)	36,003	36,003	'
Diluted EPS	'	'	'
Stated interest rate	1.75%	'	1.75%

Fair_Value_Measurements_Narrat

Fair Value Measurements (Narrative) (Details) (USD $)	Mar. 31, 2014	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2008	Mar. 31, 2014	Dec. 31, 2013	Oct. 31, 2012
		8% Series 2000 [Member]	8% Series 2000 [Member]	1.875% Convertible debentures [Member]	1.875% Convertible debentures [Member]	1.875% Convertible debentures [Member]	1.75% Convertible Debentures [Member]	1.75% Convertible Debentures [Member]	1.75% Convertible Debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'	'	'	'
Debt, principal amount	'	$30,000,000	$30,000,000	'	'	$181,500,000	$396,750,000	$396,750,000	$396,750,000
Stated interest rate	1.75%	8.00%	8.00%	1.88%	1.88%	'	1.75%	1.75%	'
Convertible debentures	'	'	'	$2,200,000	$2,200,000	'	$278,200,000	$274,000,000	'

Fair_Value_Measurements_Financ

Fair Value Measurements (Financial Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Investments	$249,630	$209,338
Fair Value, Measurements, Recurring [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Mutual funds	652	604
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Mutual funds	652	604
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Mutual funds	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Mutual funds	0	0
Fair Value, Measurements, Recurring [Member] | Federal Agency Notes [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Investments	142,332	97,585
Fair Value, Measurements, Recurring [Member] | Federal Agency Notes [Member] | Level 1 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Investments	0	0
Fair Value, Measurements, Recurring [Member] | Federal Agency Notes [Member] | Level 2 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Investments	142,332	97,585
Fair Value, Measurements, Recurring [Member] | Federal Agency Notes [Member] | Level 3 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Investments	0	0
Fair Value, Measurements, Recurring [Member] | Commercial paper [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Investments	107,298	111,753
Fair Value, Measurements, Recurring [Member] | Commercial paper [Member] | Level 1 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Investments	0	0
Fair Value, Measurements, Recurring [Member] | Commercial paper [Member] | Level 2 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Investments	107,298	111,753
Fair Value, Measurements, Recurring [Member] | Commercial paper [Member] | Level 3 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Investments	$0	$0

Fair_Value_Measurements_Financ1

Fair Value Measurements (Financial Assets And Liabilities Measured At Fair Value On A Nonrecurring Basis) (Details) (Fair Value, Measurements, Nonrecurring [Member], USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Marathon mineral properties and property, plant and equipment	'	$57,272
Exempt facility revenue bonds	31,776	30,050
Long-term investments	'	1,021
Level 1 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Marathon mineral properties and property, plant and equipment	'	0
Exempt facility revenue bonds	0	0
Long-term investments	'	1,021
Level 2 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Marathon mineral properties and property, plant and equipment	'	0
Exempt facility revenue bonds	0	0
Long-term investments	'	0
Level 3 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Marathon mineral properties and property, plant and equipment	'	57,272
Exempt facility revenue bonds	31,776	30,050
Long-term investments	'	0
1.875% Convertible debentures [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Convertible debentures, fair value	2,245	2,245
1.875% Convertible debentures [Member] | Level 1 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Convertible debentures, fair value	0	0
1.875% Convertible debentures [Member] | Level 2 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Convertible debentures, fair value	2,245	2,245
1.875% Convertible debentures [Member] | Level 3 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Convertible debentures, fair value	0	0
1.75% Convertible Debentures [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Convertible debentures, fair value	360,021	308,574
1.75% Convertible Debentures [Member] | Level 1 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Convertible debentures, fair value	0	0
1.75% Convertible Debentures [Member] | Level 2 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Convertible debentures, fair value	360,021	308,574
1.75% Convertible Debentures [Member] | Level 3 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Convertible debentures, fair value	$0	$0

Related_Parties_Narrative_Deta

Related Parties (Narrative) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2014
	Mitsubishi Corporation [Member]	Mitsubishi Corporation [Member]	Stillwater Canada Inc [Member]	Stillwater Canada Inc [Member]
				Mitsubishi Corporation [Member]
Related Party Transaction [Line Items]	'	'	'	'
Noncontrolling interest, ownership percentage by noncontrolling owners	'	'	25.00%	25.00%
Revenue from related parties	$48	$65.80	'	'