Stillwater Mining (SWC) 10-Q 6 May 16 2016 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2016	May. 05, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q1
Entity Registrant Name	STILLWATER MINING CO /DE/
Entity Central Index Key	931,948
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		121,073,388

Consolidated Statements of Comp

Consolidated Statements of Comprehensive (Loss) Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
REVENUES
Mine Production	$ 85,802	$ 125,738
PGM Recycling	47,736	74,682
Other	100	100
Total revenues	133,638	200,520
Costs of metals sold
Mine Production	67,443	80,041
PGM Recycling	46,044	72,705
Total costs of metals sold (excludes depletion, depreciation and amortization)	113,487	152,746
Depletion, depreciation and amortization
Mine Production	17,069	16,869
PGM Recycling	191	252
Total depletion, depreciation and amortization	17,260	17,121
Total costs of revenues	130,747	169,867
Exploration	2,848	1,080
General and administrative	8,297	8,345
Loss on long-term investments	0	55
(Gain) loss on disposal of property, plant and equipment	(1)	3
Total costs and expenses	141,891	179,350
OPERATING (LOSS) INCOME	(8,253)	21,170
OTHER (EXPENSE) INCOME
Other	42	884
Interest income	710	703
Interest expense	(4,182)	(5,304)
Foreign currency transaction gain (loss), net	1,192	(608)
(LOSS) INCOME BEFORE INCOME TAX BENEFIT	(10,491)	16,845
Income tax benefit	561	6,043
NET (LOSS) INCOME	(9,930)	22,888
Net loss attributable to noncontrolling interest	0	(115)
NET (LOSS) INCOME ATTRIBUTABLE TO COMMON STOCKHOLDERS	(9,930)	23,003
Other comprehensive income, net of tax
Net unrealized gain on investments available-for-sale and deferred compensation	347	136
COMPREHENSIVE (LOSS) INCOME ATTRIBUTABLE TO COMMON STOCKHOLDERS	(9,583)	23,139
Comprehensive loss attributable to noncontrolling interest	0	(115)
TOTAL COMPREHENSIVE (LOSS) INCOME	$ (9,583)	$ 23,024
Weighted average common shares outstanding
Basic (in shares)	121,071	120,521
Diluted (in shares)	121,071	156,807
Basic (loss) earnings per share attributable to common stockholders (in usd per share)	$ (0.08)	$ 0.19
Diluted (loss) earnings per share attributable to common stockholders (in usd per share)	$ (0.08)	$ 0.17

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Current assets
Cash and cash equivalents	$ 171,724	$ 147,336
Investments, at fair value (Note 11)	280,658	316,429
Inventories	105,185	102,072
Trade receivables	1,223	800
Prepaid expenses	1,295	2,821
Other current assets	26,617	21,628
Total current assets	586,702	591,086
Mineral properties	112,480	112,480
Mine development, net	467,285	460,751
Property, plant and equipment, net	104,630	109,957
Other noncurrent assets	4,142	4,115
Total assets	1,275,239	1,278,389
Current liabilities
Accounts payable	17,779	18,205
Accrued compensation and benefits	28,646	30,046
Property, production and franchise taxes payable	12,676	13,907
Current portion of long-term debt and capital lease obligations	46	657
Other current liabilities	6,768	5,286
Total current liabilities	65,915	68,101
Long-term debt and capital lease obligations	259,661	255,099
Deferred income taxes	22,235	22,761
Accrued workers compensation	6,347	6,070
Asset retirement obligation	10,947	11,027
Other noncurrent liabilities	9,826	6,102
Total liabilities	374,931	369,160
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; 121,072,613 and 121,049,471 issued and outstanding at March 31, 2016 and December 31, 2015, respectively	1,211	1,210
Paid-in capital	1,099,944	1,099,283
Accumulated deficit	(200,997)	(191,067)
Accumulated other comprehensive income (loss)	150	(197)
Total stockholders’ equity	900,308	909,229
Total liabilities and equity	$ 1,275,239	$ 1,278,389

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2016	Dec. 31, 2015
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)	121,072,613	121,049,471
Common stock, shares outstanding (in shares)	121,072,613	121,049,471

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES
Net (loss) income	$ (9,930)	$ 22,888
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depletion, depreciation and amortization	17,260	17,121
Loss on long-term investments	0	55
Amortization / accretion on investment premium / discount	607	420
(Gain) loss on disposal of property, plant and equipment	(1)	3
Foreign currency transaction (gain) loss, net	(1,192)	608
Deferred income taxes	355	(12,409)
Accretion of asset retirement obligation	208	191
Amortization of deferred debt issuance costs	217	303
Accretion of convertible debenture debt discount	4,345	4,525
Share based compensation and other benefits	732	3,438
Non-cash capitalized interest	(1,292)	(866)
Changes in operating assets and liabilities:
Inventories	(2,057)	5,997
Trade receivables	(423)	125
Prepaid expenses	1,526	1,183
Accrued compensation and benefits	(1,400)	(2,152)
Accounts payable	(83)	(2,043)
Property, production and franchise taxes payable	2,494	794
Accrued workers compensation	277	(146)
Other operating assets	(4,879)	(1,879)
Other operating liabilities	1,357	156
NET CASH PROVIDED BY OPERATING ACTIVITIES	8,121	38,312
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(18,842)	(27,902)
Proceeds from disposal of property, plant and equipment	1	0
Purchases of investments	(75,531)	(57,371)
Proceeds from maturities and sales of investments	111,250	29,839
NET CASH PROVIDED BY (USED IN) INVESTING ACTIVITIES	16,878	(55,434)
CASH FLOWS FROM FINANCING ACTIVITIES
Payments on debt and capital lease obligations	(612)	(584)
Proceeds from issuance of common stock	1	28
NET CASH USED IN FINANCING ACTIVITIES	(611)	(556)
CASH AND CASH EQUIVALENTS
Net increase (decrease)	24,388	(17,678)
Balance at beginning of period	147,336	280,286
BALANCE AT END OF PERIOD	$ 171,724	$ 262,608

General

General	3 Months Ended
	Mar. 31, 2016
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”) at March 31, 2016 , and the results of its operations and cash flows for the three months ended March 31, 2016 and 2015 , respectively. The results of operations for the first three months of 2016 are not necessarily indicative of the results to be expected for the 2016 year. The accompanying consolidated financial statements in this Quarterly Report on Form 10-Q should be read in conjunction with the consolidated financial statements and notes thereto included in the Company's 2015 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. On May 28, 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2014-09, Revenue from Contracts with Customers , which requires an entity to recognize the amount of revenue it expects to be entitled to for the transfer of promised goods or services to customers. In August 2015, the FASB issued ASU 2015-14, Deferral of the Effective Date , which defers the effective date of ASU 2014-09 by one year to January 1, 2018. ASU 2014-09 will replace most existing revenue recognition guidance in U.S. GAAP. The standard permits the use of either the retrospective or cumulative effect transition method. The Company continues to evaluate the effect that ASU 2014-09 will have on its consolidated financial statements and disclosures and has not yet selected a transition method nor has it determined the effect of the standard on its ongoing financial reporting. Early application is not permitted. On April 7, 2015, as part of its initiative to simplify and reduce complexity in financial statements, the FASB issued ASU 2015-03, Interest - Imputation, (Subtopic 835-30): Simplifying the Presentation of Debt Issuance. This ASU requires the debt issuance costs be presented in the balance sheet as a direct deduction from the carrying amount of the debt liability. Also, it requires retrospective application for all prior periods presented in the financial statements and a disclosure of the nature of and reason for the change in accounting principle, the transition method, a description of the prior-period information that has been retrospectively adjusted and the effect of the change on the financial statement line items. ASU 2015-03 is effective for financial statements issued for fiscal years beginning after December 31, 2015, and interim periods within those fiscal years. Early adoption is permitted for financial statements that have not been previously issued. The Company elected early adoption of ASU 2015-03 and has reclassified Deferred debt issue costs against the related liability for all periods presented. Prior to the adoption of ASU 2015-03, the balance reported at December 31, 2015 for total Long-term debt and capital lease obligations was $258.9 million , after adoption and reclassification of Deferred debt issue costs of $3.8 million , the total balance reported at December 31, 2015 is $255.1 million . On July 22, 2015, as part of its initiative to simplify and reduce complexity in financial statements, the FASB issued ASU 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory. ASU 2015-11, which will change the measurement principle for inventory from the lower of cost or market to the lower of cost and net realizable value. ASU 2015-11 is effective for financial statements issued for fiscal years beginning after December 15, 2016, and interim periods within those fiscal years. The Company is evaluating the effect that ASU 2015-11 will have on its consolidated financial statements and disclosures and has not yet selected a transition method nor has it determined the effect of the standard on its ongoing financial reporting. The ASU requires prospective adoption and permits early application. On February 25, 2016, the FASB issued ASU 2016-02, Leases, (Topic 840) , which requires an entity that leases assets, with terms of more than 12 months, to recognize on the balance sheet the assets and liabilities for the rights and obligations created by those leases. ASU 2016-02 is effective for financial statements issued for fiscal years beginning after December 31, 2018, and interim periods within those fiscal years. The Company is evaluating the effect that ASU 2016-02 will have on its consolidated financial statements and disclosures and has not yet selected a transition method nor has it determined the effect of the standard on its ongoing financial reporting. Early application is permitted. On March 30, 2016, as part of its initiative to simplify and reduce complexity in the financial statements, the FASB issued ASU 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employees Shared-Based Payment Accounting. The ASU will change several aspects within share based payments: (1) Accounting for Income Taxes, (2) Classification of Excess Tax Benefits on the Statement of Cash Flows, (3) Forfeitures, (4) Minimum Statutory Tax Withholding Requirements, (5) Classification of Employee Taxes Paid on the Statement of Cash Flows When an Employer Withholds Shares for Tax-Withholding Purposes, (6) Practical Expedient - Expected Term, (7) Intrinsic Value, and (8) Eliminating the Indefinite Deferral. ASU 2016-09 is effective for financial statements issued for fiscal years beginning after December 15, 2016, and interim periods within those fiscal years. The Company is evaluating the effect that ASU 2016-09 will have on its consolidated financial statements and disclosures and has not yet selected a transition method nor has it determined the effect of the standard on its ongoing financial reporting. Early application is permitted in any interim or annual period provided that the entire ASU is adopted.

Sales

Sales	3 Months Ended
	Mar. 31, 2016
Sales Revenue, Goods, Net [Abstract]
Sales	SALES MINE PRODUCTION The Company mines and processes ores 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 a third-party refiner for final processing from which they are sold to customers with whom the Company has established trading relationships. Refined platinum group metals (PGMs) in sponge form are transferred upon sale from the Company’s account at the third-party refiner to the account of the purchaser. By-product metals are normally sold at market price to customers, brokers or outside refiners. Copper and nickel by-products are typically sold at a discount to the quoted market prices. By-product sales (gold, nickel, mined rhodium, copper and silver) are included in revenues from Mine Production. During each of the three months ended March 31, 2016 and 2015 , total by-product sales were $5.1 million and $6.7 million , respectively. In July 2014, the Company executed five -year supply and refining agreements with Johnson Matthey (JM). Under the terms of these agreements, JM has an exclusive five -year right to refine all of the PGM filter cake the Company produces at its Columbus, Montana facilities. JM also has the right to purchase all of the Company's mine production of palladium and platinum at competitive market prices (except for platinum sales under the Company's sales agreement with Tiffany & Co., which are specifically excluded from the JM agreements) and has the right to bid for any recycling volumes the Company has available. Other provisions of the agreements include a good-faith effort by JM to assist in growing the Company's recycling volumes and the sharing of market intelligence to the extent permitted by law. The Company has the right to exit the JM PGM supply arrangement in return for the payment of a nominal fee. In addition, the Company, in its sole discretion, may elect to terminate the refining arrangement after four years . In accordance with the terms of the JM PGM supply agreement, for the three months ended March 31, 2016 and 2015 all Company sales of mined PGMs, other than the platinum sales under the Company's sales agreement with Tiffany & Co., were to JM. PGM RECYCLING The Company purchases spent catalyst materials from third-parties for recycling and processes these materials within its facilities in Columbus, Montana to recover palladium, platinum and rhodium for sale. The Company has entered into sourcing arrangements for catalyst materials with various suppliers. Under these sourcing arrangements the Company may advance cash as general working capital or against a shipment of material shortly before actually receiving the physical shipment at the Company's processing facilities. These advances are included in Other current assets on the Company’s Consolidated Balance Sheets until such time as the materials have 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 cash advance was made until the out-turn date of the inventory from the final refiner. The Company also accepts materials supplied from third-parties on a tolling basis, processes it for a fee and returns the recovered metals to the suppli TOTAL SALES Total sales to significant customers as a percentage of total revenues for the three months ended March 31, 2016 and 2015 were as follows: Three Months Ended March 31, 2016 2015 Customer A 80 % 74 %

Noncontrolling Interest

Noncontrolling Interest	3 Months Ended
	Mar. 31, 2016
Noncontrolling Interest [Abstract]
Noncontrolling Interest	NONCONTROLLING INTEREST In the fourth quarter of 2015, the Company purchased the 25% interest held by Mitsubishi Corporation (Mitsubishi) in the Company's wholly-owned subsidiary, Stillwater Canada Inc (SCI) which holds the Marathon PGM-copper assets. The Company paid total cash consideration of $5.2 million which was comprised of $1.0 million in cash and the equivalent of 25% of the total cash and cash equivalents held by SCI. Prior to the repurchase, Mitsubishi's 25% interest in the SCI net loss in each period was shown as Net loss attributable to noncontrolling interest in the Company's Consolidated Statements of Comprehensive (Loss) Income . The amount of the loss was added back to the Company's reported Net (loss) income in each period in arriving at Net (loss) income attributable to common stockholders . The reported Net loss attributable to noncontrolling interest for the three months ended March 31, 2015 was $0.1 million .

Derivative Instruments

Derivative Instruments	3 Months Ended
	Mar. 31, 2016
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 PGM market commodity prices. COMMODITY DERIVATIVES PGM Recycling The Company customarily enters into fixed forward sales relating to PGM recycling of catalyst and other industrial sourced materials. 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 to set in advance the pricing for metals acquired and processed in its recycling segment. 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 this forward price is also used to set the acquisition price the Company pays for recycling materials, 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 purchases and normal sales. All of the Company's fixed forward sales contracts open at March 31, 2016 , will settle at various periods through September 2016 . 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. At March 31, 2016 , and December 31, 2015, no margin deposits were outstanding or due. The following is a summary of the Company's outstanding commodity derivatives in its Recycling Business Segment at March 31, 2016 : PGM Recycling: Fixed Forward Contracts Platinum Palladium Rhodium Settlement Period Ounces Average Price/Ounce Ounces Average Price/Ounce Ounces Average Price/Ounce Second Quarter 2016 21,120 $ 915 39,807 $ 532 4,608 $ 653 Third Quarter 2016 4,203 $ 963 4,072 $ 548 1,536 $ 684

Share Compensation Plans

Share Compensation Plans	3 Months Ended
	Mar. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share Compensation Plans	SHARE COMPENSATION PLANS EQUITY PLANS The Company sponsors equity plans (the Plans) that enable the Company to grant equity based compensation to employees and non-employee directors. The Company currently issues restricted stock units as incentive compensation under the Plans. In total approximately 11.6 million shares of common stock have been authorized under the Plans, including approximately 5.0 million , 5.2 million , and 1.4 million authorized shares for the 2012 Equity Incentive Plan, 2004 Equity Incentive Plan and the General Employee Plan, respectively. Approximately 4.1 million shares were available and reserved for grant under the 2012 Equity Incentive Plan at March 31, 2016 . 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. NONVESTED SHARES Time-Based Restricted Stock Unit Awards Time-based restricted stock unit awards provide the participant with the right to receive a number of shares of the Company's common stock upon vesting of the awards provided the participant is employed by the Company on the vesting date. Time-based awards are valued using the Company's common stock price on the date of grant. Time-based awards are not entitled to any dividend equivalents with respect to the restricted stock units unless otherwise determined by the Board, 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. Nonvested time-based share activity during the three months ended March 31, 2016 , is detailed in the following table: Nonvested Shares Weighted-Average Grant-Date Fair Value Nonvested time-based shares at January 1, 2016 186,655 $ 13.97 Granted 206,974 8.03 Vested (33,080 ) 13.88 Forfeited — — Nonvested time-based shares at March 31, 2016 360,549 $ 10.68 Total compensation expense, included within General and administrative in the Company's Consolidated Statements of Comprehensive (Loss) Income related to grants of time-based nonvested shares for the three months ended March 31, 2016 and 2015 was $0.4 million and $0.3 million , respectively. 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 common stock depending on achievement of specific measurable performance criteria. The number of shares earned is determined at the end of each performance period, generally three years, based on the actual performance criteria predetermined by the Compensation Committee at the time of grant. 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. For awards that contain performance-based conditions, and for which 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. The Company grants performance-based restricted stock unit awards under its Long Term Incentive Plan (LTIP). The payout of the awards is dependent upon distinct components with separate sub-targets. The sub-targets are either market-based or performance-based and classified as either equity or liability. The market-based sub-targets are valued using a Monte Carlo simulation valuation model on the date of grant. The fair value of the liability classified sub-targets are remeasured each reporting period. The existence of a market condition requires recognition of compensation cost for the performance share awards over the requisite period regardless of whether the market condition is satisfied. Total compensation expense, included within General and administrative in the Company's Consolidated Statements of Comprehensive (Loss) Income , related to grants of performance-based shares for the three months ended March 31, 2016 and 2015 was $0.4 million and $0.1 million , respectively. Performance-based awards are not entitled to any dividend equivalents with respect to the restricted stock units unless otherwise determined by the Board, 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. Nonvested performance-based share activity during the first three months of 2016 is detailed in the following table: Nonvested Shares Weighted-Average Grant-Date Fair Value Nonvested performance-based shares at January 1, 2016 379,277 $ 15.34 Granted * 186,285 11.45 Vested — Forfeited * — — Nonvested performance-based shares at March 31, 2016 565,562 $ 14.06 * The number of performance-based shares granted is based on the target award amounts in the performance share grant agreements. The following table presents the compensation expense of the nonvested shares outstanding at March 31, 2016 , to be recognized over the remaining vesting periods: (In thousands) Time-based shares Performance -based shares Remaining 2016 $ 1,655 $ 1,737 2017 1,198 1,607 2018 577 771 Total $ 3,430 $ 4,115

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2016
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. These assets and liabilities reflect 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 credit 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. In assessing the realizability of deferred tax assets, the Company considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The Company considers the scheduled reversal of deferred tax liabilities, projected future taxable income and tax planning strategies in making this assessment. The Company has a valuation allowance in 2016 and 2015 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, and certain tax credits. The benefit for income taxes for the three months ended March 31, 2016 is related to the carryback of the U.S. Federal and state current year losses and the deferred tax benefits from certain foreign jurisdictions, offset by an increase in uncertain (FIN 48) tax positions in the U.S. Changes in the Company’s net deferred tax assets and liabilities have been partially offset by a corresponding change in the valuation allowance. The Company recognized an income tax benefit for the three months ended March 31, 2016 and 2015, of $0.6 million and $6.0 million , respectively. The current year loss, partially offset by the discrete provision of $3.4 million for an increase in uncertain (FIN 48) tax positions, is primarily responsible for the tax benefit for the three months ended March 31, 2016. The partial restructure of internal operations and the creation of a separate metal sales and trading subsidiary was primarily responsible for the income tax benefit recognized for the three months ended March 31, 2015, which included an $8.6 million discrete tax benefit. The Company’s policy is to recognize interest and penalties on unrecognized tax benefits in Income tax benefit in the Company's Consolidated Statements of Comprehensive (Loss) Income . The Company had uncertain benefits of $3.4 million at March 31, 2016 . Interest and penalties of $0.1 million have been accrued at March 31, 2016 . The Company anticipates there could be a change in uncertain tax positions during the next twelve months. The Company made income tax payments of $0.3 million and $8.2 million in the three months ended March 31, 2016 and 2015 , respectively. Tax years still open for examination by the taxing authorities are the years ended December 31, 2014, 2013, 2012 and 2011, although net operating loss and credit carryforwards from all years are subject to examination and adjustment for the three years following the year in which the carryforwards are utilized.

Debt and Capital Lease Obligati

Debt and Capital Lease Obligations	3 Months Ended
	Mar. 31, 2016
Debt Disclosure [Abstract]
Debt and Capital Lease Obligations	DEBT AND CAPITAL LEASE OBLIGATIONS 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 each debenture with a warrant initially exercisable for 30.2481 shares at an exercise price of $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 call 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 . In the third quarter of 2015, the Company repurchased $61.6 million of the outstanding principal of the 1.75% debentures, paying cash of $59.4 million . The Company reduced the debt component by $50.7 million , which includes a reduction of the debt discount by $10.9 million . The difference between the book value and the fair value (including $0.7 million of debt and equity issuance costs) of the debt component resulted in a $4.2 million loss. 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, 2016 was approximately $259.1 million which is net of unamortized discount of $72.4 million and $3.6 million deferred debt issue costs. The balance outstanding at December 31, 2015 was $254.6 million , which was net of unamortized discount of $76.8 million and $3.8 million of deferred debt issue costs. 1.875% CONVERTIBLE DEBENTURES Holders of the remaining $0.5 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 including a change in control. Effective March 22, 2013, the Company has the right at its discretion to redeem the remaining $0.5 million of outstanding 1.875% debentures for cash at any time prior to maturity. The outstanding balance at March 31, 2016 and December 31, 2015 , of $0.5 million aggregate principal amount, is reported as a long-term debt obligation. In the third quarter of 2015, the Company repurchased $1.7 million of the outstanding principal of the 1.875% debentures, paying cash of $1.6 million and recorded a gain of approximately $0.1 million . 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 . The Company also paid an unused line fee on the committed but unutilized balance under the facility at a rate per annum of 0.375% or 0.5% , depending on utilization of the facility. The Company terminated this credit facility on December 31, 2015, incurring expenses and fees of approximately $0.2 million . The following table reflects the amortization of debt issuance costs, interest expense and cash payments on the Company's outstanding debt for the three months ended March 31, 2016 and 2015: Three months ended March 31, (In thousands) 2016 2015 1.75% Convertible Debentures Amortization of debt issuance costs $ 217 $ 236 Interest expense, net of capitalized interest $ 3,993 $ 5,001 Cash payments for interest $ — $ 3,472 1.875% Convertible Debentures Interest expense, net of capitalized interest $ — $ — Cash payments for interest $ 5 $ — Asset-Backed Revolving Credit Facility Amortization of debt issuance costs $ — $ 67 Fees $ — $ 251 The Company's total current and long-term debt balances at March 31, 2016 and December 31, 2015 were as follows: March 31, 2016 December 31, 2015 (In thousands) Current Long-Term Current Long-Term 1.75% Convertible Debentures Aggregate principal $ — $ 335,150 $ — $ 335,150 Debt discount — (72,409 ) — (76,754 ) Deferred debt issue costs — (3,604 ) — (3,821 ) Debt balance — 259,137 — 254,575 1.875% Convertible Debentures — 524 — 524 Capital Lease Obligation 46 — 580 — Small Land Purchase — — 77 — Total debt balances $ 46 $ 259,661 $ 657 $ 255,099 CAPITALIZED INTEREST The Company capitalizes interest incurred on its various debt instruments as a cost of specific and identified areas under development. For the three months ended March 31, 2016 and 2015 , the Company capitalized interest of $1.9 million and $1.3 million , respectively. Capitalized interest is recorded as a reduction to Interest expense in the Company's Consolidated Statements of Comprehensive (Loss) Income .

Mineral Properties and Mine Dev

Mineral Properties and Mine Development	3 Months Ended
	Mar. 31, 2016
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: March 31, December 31, (In thousands) 2016 2015 Mineral Properties: Montana, United States of America Stillwater Mine $ 1,950 $ 1,950 Ontario, Canada Marathon properties 8,560 8,560 San Juan, Argentina Altar property 101,970 101,970 Mine Development: Montana, United States of America Stillwater Mine 713,614 697,781 East Boulder Mine 224,475 220,281 1,050,569 1,030,542 Accumulated depletion and amortization (470,804 ) (457,311 ) Total mineral properties and mine development, net $ 579,765 $ 573,231

Property, Plant and Equipment

Property, Plant and Equipment	3 Months Ended
	Mar. 31, 2016
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	PROPERTY, PLANT AND EQUIPMENT Property, plant and equipment reflected in the accompanying consolidated balance sheets consisted of the following: March 31, December 31, (In thousands) 2016 2015 Machinery and equipment $ 161,675 $ 161,292 Buildings and structural components 173,795 173,580 Land 11,740 11,740 Construction-in-progress: Stillwater Mine 2,731 2,615 East Boulder Mine 266 435 Marathon 148 148 Processing facilities and other 2,360 1,982 352,715 351,792 Accumulated depreciation (248,085 ) (241,835 ) Total property, plant, and equipment, net $ 104,630 $ 109,957 The Company's total capital outlay for mine development and property, plant and equipment for the three months ended March 31, 2016 and 2015 were as follows: Three Months Ended March 31, (In thousands) 2016 2015 Stillwater Mine $ 16,770 $ 21,013 East Boulder Mine 4,078 4,269 Other 418 3,093 Total U.S. capital expenditures 21,266 28,375 Non-cash capitalized interest and depreciation (2,609 ) (2,167 ) Change in accounts payables for capital expenditures 185 1,694 Cash capital spend for the period $ 18,842 $ 27,902

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2016
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 has agreements in place to sell its PGMs from mine production. 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 materials to recover the PGMs contained in the materials. The Company purchases catalyst materials 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 materials from 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 mineral property assets. The exploration-stage Marathon mineral properties include a large PGM and copper deposit located near the town of Marathon, Ontario, Canada as well as additional mineral properties located adjacent to the Marathon properties. The South American Properties segment consists of the Peregrine Metals Ltd. assets. The principal Peregrine property is the Altar property, an exploration-stage copper-gold resource located in the San Juan province of Argentina. The All Other group primarily consists of assets, including investments, revenues, and expenses of various corporate and support functions. 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, 2016 Mine Production PGM Recycling Canadian Properties All Other Total Revenues $ 85,802 $ 47,736 $ — $ — $ 100 $ 133,638 Depletion, depreciation and amortization $ 17,069 $ 191 $ — $ — $ — $ 17,260 General and administrative expenses $ — $ — $ 136 $ 308 $ 7,853 $ 8,297 Interest income $ — $ 293 $ — $ 1 $ 416 $ 710 Interest expense $ — $ — $ — $ — $ 4,182 $ 4,182 Income (loss) before income taxes $ 1,291 $ 1,793 $ (168 ) $ (1,243 ) $ (12,164 ) $ (10,491 ) Capital expenditures $ 18,435 $ 10 $ — $ — $ 397 $ 18,842 Total assets $ 621,003 $ 33,349 $ 26,327 $ 105,749 $ 488,811 $ 1,275,239 (In thousands) South American Properties Three Months Ended March 31, 2015 Mine Production PGM Recycling Canadian Properties All Other Total Revenues $ 125,738 $ 74,682 $ — $ — $ 100 $ 200,520 Depletion, depreciation and amortization $ 16,869 $ 252 $ — $ — $ — $ 17,121 General and administrative expenses $ — $ — $ 235 $ 182 $ 7,928 $ 8,345 Interest income $ — $ 403 $ 3 $ 14 $ 283 $ 703 Interest expense $ — $ — $ — $ — $ 5,304 $ 5,304 Income (loss) before income taxes $ 28,828 $ 2,127 $ (433 ) $ (773 ) $ (12,904 ) $ 16,845 Capital expenditures $ 25,548 $ 59 $ — $ — $ 2,295 $ 27,902 Total assets $ 607,117 $ 57,740 $ 74,734 $ 105,795 $ 563,657 $ 1,409,043

Investments

Investments	3 Months Ended
	Mar. 31, 2016
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 value in the financial statements with unrealized gains or losses recorded in Other comprehensive income in the Company's Consolidated Statements of Comprehensive (Loss) Income . At the time the securities are sold or otherwise disposed of, gross realized gains and losses are included in Net (loss) income . Gross realized gains and losses are based on the carrying value (cost, net of discounts or premiums) of the sold investment. The amounts reclassified out of Other comprehensive income during the three months ended March 31, 2016 and 2015 , were insignificant. The amortized cost, gross unrealized gains, gross unrealized losses, and fair value of available-for-sale investment securities by major security type and class of security at March 31, 2016 , and December 31, 2015 were as follows: Investments (In thousands) Amortized cost Gross unrealized gains Gross unrealized losses Fair value 2016 Federal agency notes $ 248,200 $ 49 $ (85 ) $ 248,164 Commercial paper 32,480 14 — 32,494 Subtotal 280,680 63 (85 ) 280,658 Mutual funds 656 255 — 911 Total $ 281,336 $ 318 $ (85 ) $ 281,569 2015 Federal agency notes $ 285,276 $ — $ (519 ) $ 284,757 Commercial paper 31,730 — (58 ) 31,672 Subtotal 317,006 — (577 ) 316,429 Mutual funds 482 261 — 743 Total $ 317,488 $ 261 $ (577 ) $ 317,172 The mutual funds included in the investment table above are included in Other noncurrent assets on the Company's Consolidated Balance Sheets . Included in the investments balance at March 31, 2016 and December 31, 2015 is $18.5 million which has been reserved as collateral on the Company's undrawn letters of credit of approximately $17.5 million . The maturities of available-for-sale securities at March 31, 2016 were as follows: (In thousands) Amortized cost Fair value Federal agency notes Due in one year or less $ 172,432 $ 172,433 Due after one year through two years 75,768 75,731 Total $ 248,200 $ 248,164 Commercial paper Due in one year or less $ 18,990 $ 18,990 Due after one year through two years 13,490 13,504 Total $ 32,480 $ 32,494 The Company has long-term investments in several Canadian junior exploration companies, recorded on the Company's Consolidated Balance Sheets at cost. These long-term investments totaled approximately $0.5 million at March 31, 2016 and December 31, 2015, and are recorded in Other noncurrent assets on the Company's Consolidated Balance Sheets .

Inventories

Inventories	3 Months Ended
	Mar. 31, 2016
Inventory Disclosure [Abstract]
Inventories	INVENTORIES The Company carries items in its inventories at the lower of cost or market value. If market value in any period falls below the carrying value, the carrying value of the inventory item is reduced to its market value. 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 reduction to inventory value was necessary in the first three months of 2016 or 2015 . 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 and amortization and other overhead costs relating to mining and processing activities incurred as of such date. Costs are aggregated and averaged for mined material carried in inventory. The costs of PGM recycling 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. Costs incurred are allocated and tracked separately for each specific lot of recycling material (including material tolled on behalf of others). Inventories reflected in the accompanying balance sheets consisted of the following: March 31, December 31, (In thousands) 2016 2015 Metals inventory Raw ore $ 4,490 $ 4,234 Concentrate and in-process 55,888 43,727 Finished goods 24,473 32,618 Total metals inventory 84,851 80,579 Materials and supplies 20,334 21,493 Total inventory $ 105,185 $ 102,072

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2016
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 shares of common stock 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 or nonvested shares were exercised or vested, the contingently issuable shares were issued and the Company’s convertible debt was converted. The Company currently has only one class of shares of capital stock outstanding. No adjustment was made to reported net loss attributable to common stockholders when calculating diluted loss per share attributable to common stockholders at March 31, 2016 because the effect would have been anti-dilutive. There was no effect of outstanding nonvested shares on diluted weighted average shares outstanding for the three months ended March 31, 2016 because the Company reported a consolidated net loss attributable to common stockholders and inclusion of these shares would have been anti-dilutive. Potential dilutive common shares include those associated with outstanding stock options, restricted stock units, performance shares and convertible debentures. The following table shows the shares that were excluded from the computation of diluted earnings per share, for the three months ended March 31, 2016 and 2015: Three Months Ended March 31, (In thousands) 2016 2015 Stock options 1 — Nonvested shares 309 — Contingently issuable 255 160 1.875% Convertible debentures, net of tax 22 — 1.75% Convertible debentures, net of tax 30,413 — In calculating earnings per share attributable to common stockholders for the three months ended March 31, 2015 , reported consolidated net income attributable to common stockholders was adjusted for interest expense, net of capitalized interest (including amortization expense of deferred debt fees), a related income tax effect and the loss attributable to the noncontrolling interest in computing basic and diluted earnings per share attributable to common stockholders. Reconciliations showing the computation of basic and diluted shares and the related impact on income for the three months ended March 31, 2015, is provided in the following table: Three Months Ended March 31, 2015 (In thousands, except per share amounts) Income (Numerator) Weighted Average Shares (Denominator) Per Share Amount Basic EPS Net income attributable to common stockholders $ 23,003 120,521 $ 0.19 Effect of Dilutive Securities Stock options — 3 Nonvested shares — 31 Contingently issuable shares — 154 1.875% Convertible debentures, net of tax — 95 1.75% Convertible debentures, net of tax 4,424 36,003 Diluted EPS Net income attributable to common stockholders and assumed conversions $ 27,427 156,807 $ 0.17

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2016
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, 2016 , and December 31, 2015 , consisted of the following: (In thousands) Fair Value Measurements At March 31, 2016 Total Level 1 Level 2 Level 3 Money market fund $ 91,721 $ 91,721 $ — $ — Mutual funds $ 911 $ 911 $ — $ — Investments Federal agency notes $ 248,164 $ — $ 248,164 $ — Commercial paper $ 32,494 $ — $ 32,494 $ — (In thousands) Fair Value Measurements At December 31, 2015 Total Level 1 Level 2 Level 3 Money market fund $ 54,761 $ 54,761 $ — $ — Mutual funds $ 743 $ 743 $ — $ — Investments Federal agency notes $ 284,757 $ — $ 284,757 $ — Commercial paper $ 31,672 $ — $ 31,672 $ — The money market funds are recorded in Cash and cash equivalents on the Company's Consolidated Balance Sheets . The fair value of the mutual funds is based on market prices that are readily available and are recorded in Other noncurrent assets on the Company's Consolidated Balance Sheets . 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 income (loss) on the Company's Consolidated Balance Sheets . Assets and liabilities measured at fair value on a nonrecurring basis at March 31, 2016 , and December 31, 2015 , consisted of the following: (In thousands) Fair Value Measurements At March 31, 2016 Total Level 1 Level 2 Level 3 1.875% Convertible debentures $ 524 $ — $ 524 $ — 1.75% Convertible debentures $ 301,127 $ — $ 301,127 $ — (In thousands) Fair Value Measurements At December 31, 2015 Total Level 1 Level 2 Level 3 1.875% Convertible Debentures $ 524 $ — $ 524 $ — 1.75% Convertible Debentures $ 285,446 $ — $ 285,446 $ — Long-term investments $ 524 $ 524 $ — $ — The Company determined the fair value of the liability component of its outstanding 1.75% convertible debentures at March 31, 2016 and December 31, 2015 by using observable market based information for debt instruments of similar amounts and duration. The Company used the book value of its outstanding 1.875% convertible debentures to represent the fair value at March 31, 2016 and December 31, 2015 .The fair value of the Company's long-term investments in certain Canadian junior exploration companies at December 31, 2015 is based on quoted market prices which are readily available.

Related Parties

Related Parties	3 Months Ended
	Mar. 31, 2016
Related Party Transactions [Abstract]
Related Parties	RELATED PARTIES The Company purchased Mitsubishi's 25% ownership interest in the Company's subsidiary, Stillwater Canada Inc (SCI) in the fourth quarter of 2015. The Company made PGM sales of $15.9 million to Mitsubishi in the three months ended March 31, 2015 .

General (Policies)

General (Policies)	3 Months Ended
	Mar. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Use of Estimates	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.
New Accounting Pronouncements	On May 28, 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2014-09, Revenue from Contracts with Customers , which requires an entity to recognize the amount of revenue it expects to be entitled to for the transfer of promised goods or services to customers. In August 2015, the FASB issued ASU 2015-14, Deferral of the Effective Date , which defers the effective date of ASU 2014-09 by one year to January 1, 2018. ASU 2014-09 will replace most existing revenue recognition guidance in U.S. GAAP. The standard permits the use of either the retrospective or cumulative effect transition method. The Company continues to evaluate the effect that ASU 2014-09 will have on its consolidated financial statements and disclosures and has not yet selected a transition method nor has it determined the effect of the standard on its ongoing financial reporting. Early application is not permitted. On April 7, 2015, as part of its initiative to simplify and reduce complexity in financial statements, the FASB issued ASU 2015-03, Interest - Imputation, (Subtopic 835-30): Simplifying the Presentation of Debt Issuance. This ASU requires the debt issuance costs be presented in the balance sheet as a direct deduction from the carrying amount of the debt liability. Also, it requires retrospective application for all prior periods presented in the financial statements and a disclosure of the nature of and reason for the change in accounting principle, the transition method, a description of the prior-period information that has been retrospectively adjusted and the effect of the change on the financial statement line items. ASU 2015-03 is effective for financial statements issued for fiscal years beginning after December 31, 2015, and interim periods within those fiscal years. Early adoption is permitted for financial statements that have not been previously issued. The Company elected early adoption of ASU 2015-03 and has reclassified Deferred debt issue costs against the related liability for all periods presented. Prior to the adoption of ASU 2015-03, the balance reported at December 31, 2015 for total Long-term debt and capital lease obligations was $258.9 million , after adoption and reclassification of Deferred debt issue costs of $3.8 million , the total balance reported at December 31, 2015 is $255.1 million . On July 22, 2015, as part of its initiative to simplify and reduce complexity in financial statements, the FASB issued ASU 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory. ASU 2015-11, which will change the measurement principle for inventory from the lower of cost or market to the lower of cost and net realizable value. ASU 2015-11 is effective for financial statements issued for fiscal years beginning after December 15, 2016, and interim periods within those fiscal years. The Company is evaluating the effect that ASU 2015-11 will have on its consolidated financial statements and disclosures and has not yet selected a transition method nor has it determined the effect of the standard on its ongoing financial reporting. The ASU requires prospective adoption and permits early application. On February 25, 2016, the FASB issued ASU 2016-02, Leases, (Topic 840) , which requires an entity that leases assets, with terms of more than 12 months, to recognize on the balance sheet the assets and liabilities for the rights and obligations created by those leases. ASU 2016-02 is effective for financial statements issued for fiscal years beginning after December 31, 2018, and interim periods within those fiscal years. The Company is evaluating the effect that ASU 2016-02 will have on its consolidated financial statements and disclosures and has not yet selected a transition method nor has it determined the effect of the standard on its ongoing financial reporting. Early application is permitted. On March 30, 2016, as part of its initiative to simplify and reduce complexity in the financial statements, the FASB issued ASU 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employees Shared-Based Payment Accounting. The ASU will change several aspects within share based payments: (1) Accounting for Income Taxes, (2) Classification of Excess Tax Benefits on the Statement of Cash Flows, (3) Forfeitures, (4) Minimum Statutory Tax Withholding Requirements, (5) Classification of Employee Taxes Paid on the Statement of Cash Flows When an Employer Withholds Shares for Tax-Withholding Purposes, (6) Practical Expedient - Expected Term, (7) Intrinsic Value, and (8) Eliminating the Indefinite Deferral. ASU 2016-09 is effective for financial statements issued for fiscal years beginning after December 15, 2016, and interim periods within those fiscal years. The Company is evaluating the effect that ASU 2016-09 will have on its consolidated financial statements and disclosures and has not yet selected a transition method nor has it determined the effect of the standard on its ongoing financial reporting. Early application is permitted in any interim or annual period provided that the entire ASU is adopted.

Sales (Tables)

Sales (Tables)	3 Months Ended
	Mar. 31, 2016
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 months ended March 31, 2016 and 2015 were as follows: Three Months Ended March 31, 2016 2015 Customer A 80 % 74 %

Derivative Instruments (Tables)

Derivative Instruments (Tables)	3 Months Ended
	Mar. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Company's outstanding commodity derivatives	The following is a summary of the Company's outstanding commodity derivatives in its Recycling Business Segment at March 31, 2016 : PGM Recycling: Fixed Forward Contracts Platinum Palladium Rhodium Settlement Period Ounces Average Price/Ounce Ounces Average Price/Ounce Ounces Average Price/Ounce Second Quarter 2016 21,120 $ 915 39,807 $ 532 4,608 $ 653 Third Quarter 2016 4,203 $ 963 4,072 $ 548 1,536 $ 684

Share Compensation Plans (Table

Share Compensation Plans (Tables)	3 Months Ended
	Mar. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Changes In The Company's Nonvested Shares	Nonvested performance-based share activity during the first three months of 2016 is detailed in the following table: Nonvested Shares Weighted-Average Grant-Date Fair Value Nonvested performance-based shares at January 1, 2016 379,277 $ 15.34 Granted * 186,285 11.45 Vested — Forfeited * — — Nonvested performance-based shares at March 31, 2016 565,562 $ 14.06 * The number of performance-based shares granted is based on the target award amounts in the performance share grant agreements. Nonvested time-based share activity during the three months ended March 31, 2016 , is detailed in the following table: Nonvested Shares Weighted-Average Grant-Date Fair Value Nonvested time-based shares at January 1, 2016 186,655 $ 13.97 Granted 206,974 8.03 Vested (33,080 ) 13.88 Forfeited — — Nonvested time-based shares at March 31, 2016 360,549 $ 10.68
Compensation Expense of Nonvested Shares	The following table presents the compensation expense of the nonvested shares outstanding at March 31, 2016 , to be recognized over the remaining vesting periods: (In thousands) Time-based shares Performance -based shares Remaining 2016 $ 1,655 $ 1,737 2017 1,198 1,607 2018 577 771 Total $ 3,430 $ 4,115

Debt and Capital Lease Obliga25

Debt and Capital Lease Obligations (Tables)	3 Months Ended
	Mar. 31, 2016
Debt Disclosure [Abstract]
Schedule of Debt Issuance Costs, Interest Expense and Cash Paid For Interest	The following table reflects the amortization of debt issuance costs, interest expense and cash payments on the Company's outstanding debt for the three months ended March 31, 2016 and 2015: Three months ended March 31, (In thousands) 2016 2015 1.75% Convertible Debentures Amortization of debt issuance costs $ 217 $ 236 Interest expense, net of capitalized interest $ 3,993 $ 5,001 Cash payments for interest $ — $ 3,472 1.875% Convertible Debentures Interest expense, net of capitalized interest $ — $ — Cash payments for interest $ 5 $ — Asset-Backed Revolving Credit Facility Amortization of debt issuance costs $ — $ 67 Fees $ — $ 251
Schedule of Current and Long-term Debt	The Company's total current and long-term debt balances at March 31, 2016 and December 31, 2015 were as follows: March 31, 2016 December 31, 2015 (In thousands) Current Long-Term Current Long-Term 1.75% Convertible Debentures Aggregate principal $ — $ 335,150 $ — $ 335,150 Debt discount — (72,409 ) — (76,754 ) Deferred debt issue costs — (3,604 ) — (3,821 ) Debt balance — 259,137 — 254,575 1.875% Convertible Debentures — 524 — 524 Capital Lease Obligation 46 — 580 — Small Land Purchase — — 77 — Total debt balances $ 46 $ 259,661 $ 657 $ 255,099

Mineral Properties and Mine D26

Mineral Properties and Mine Development (Tables)	3 Months Ended
	Mar. 31, 2016
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: March 31, December 31, (In thousands) 2016 2015 Mineral Properties: Montana, United States of America Stillwater Mine $ 1,950 $ 1,950 Ontario, Canada Marathon properties 8,560 8,560 San Juan, Argentina Altar property 101,970 101,970 Mine Development: Montana, United States of America Stillwater Mine 713,614 697,781 East Boulder Mine 224,475 220,281 1,050,569 1,030,542 Accumulated depletion and amortization (470,804 ) (457,311 ) Total mineral properties and mine development, net $ 579,765 $ 573,231

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	3 Months Ended
	Mar. 31, 2016
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant and Equipment	Property, plant and equipment reflected in the accompanying consolidated balance sheets consisted of the following: March 31, December 31, (In thousands) 2016 2015 Machinery and equipment $ 161,675 $ 161,292 Buildings and structural components 173,795 173,580 Land 11,740 11,740 Construction-in-progress: Stillwater Mine 2,731 2,615 East Boulder Mine 266 435 Marathon 148 148 Processing facilities and other 2,360 1,982 352,715 351,792 Accumulated depreciation (248,085 ) (241,835 ) Total property, plant, and equipment, net $ 104,630 $ 109,957
Schedule Capital Expenditures	The Company's total capital outlay for mine development and property, plant and equipment for the three months ended March 31, 2016 and 2015 were as follows: Three Months Ended March 31, (In thousands) 2016 2015 Stillwater Mine $ 16,770 $ 21,013 East Boulder Mine 4,078 4,269 Other 418 3,093 Total U.S. capital expenditures 21,266 28,375 Non-cash capitalized interest and depreciation (2,609 ) (2,167 ) Change in accounts payables for capital expenditures 185 1,694 Cash capital spend for the period $ 18,842 $ 27,902

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2016
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, 2016 Mine Production PGM Recycling Canadian Properties All Other Total Revenues $ 85,802 $ 47,736 $ — $ — $ 100 $ 133,638 Depletion, depreciation and amortization $ 17,069 $ 191 $ — $ — $ — $ 17,260 General and administrative expenses $ — $ — $ 136 $ 308 $ 7,853 $ 8,297 Interest income $ — $ 293 $ — $ 1 $ 416 $ 710 Interest expense $ — $ — $ — $ — $ 4,182 $ 4,182 Income (loss) before income taxes $ 1,291 $ 1,793 $ (168 ) $ (1,243 ) $ (12,164 ) $ (10,491 ) Capital expenditures $ 18,435 $ 10 $ — $ — $ 397 $ 18,842 Total assets $ 621,003 $ 33,349 $ 26,327 $ 105,749 $ 488,811 $ 1,275,239 (In thousands) South American Properties Three Months Ended March 31, 2015 Mine Production PGM Recycling Canadian Properties All Other Total Revenues $ 125,738 $ 74,682 $ — $ — $ 100 $ 200,520 Depletion, depreciation and amortization $ 16,869 $ 252 $ — $ — $ — $ 17,121 General and administrative expenses $ — $ — $ 235 $ 182 $ 7,928 $ 8,345 Interest income $ — $ 403 $ 3 $ 14 $ 283 $ 703 Interest expense $ — $ — $ — $ — $ 5,304 $ 5,304 Income (loss) before income taxes $ 28,828 $ 2,127 $ (433 ) $ (773 ) $ (12,904 ) $ 16,845 Capital expenditures $ 25,548 $ 59 $ — $ — $ 2,295 $ 27,902 Total assets $ 607,117 $ 57,740 $ 74,734 $ 105,795 $ 563,657 $ 1,409,043

Investments (Tables)

Investments (Tables)	3 Months Ended
	Mar. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Schedule of Available-for-sale Securities	The amortized cost, gross unrealized gains, gross unrealized losses, and fair value of available-for-sale investment securities by major security type and class of security at March 31, 2016 , and December 31, 2015 were as follows: Investments (In thousands) Amortized cost Gross unrealized gains Gross unrealized losses Fair value 2016 Federal agency notes $ 248,200 $ 49 $ (85 ) $ 248,164 Commercial paper 32,480 14 — 32,494 Subtotal 280,680 63 (85 ) 280,658 Mutual funds 656 255 — 911 Total $ 281,336 $ 318 $ (85 ) $ 281,569 2015 Federal agency notes $ 285,276 $ — $ (519 ) $ 284,757 Commercial paper 31,730 — (58 ) 31,672 Subtotal 317,006 — (577 ) 316,429 Mutual funds 482 261 — 743 Total $ 317,488 $ 261 $ (577 ) $ 317,172
Schedule of Maturities of Available-for-sale Securities	The maturities of available-for-sale securities at March 31, 2016 were as follows: (In thousands) Amortized cost Fair value Federal agency notes Due in one year or less $ 172,432 $ 172,433 Due after one year through two years 75,768 75,731 Total $ 248,200 $ 248,164 Commercial paper Due in one year or less $ 18,990 $ 18,990 Due after one year through two years 13,490 13,504 Total $ 32,480 $ 32,494

Inventories (Tables)

Inventories (Tables)	3 Months Ended
	Mar. 31, 2016
Inventory Disclosure [Abstract]
Components of Inventories	Inventories reflected in the accompanying balance sheets consisted of the following: March 31, December 31, (In thousands) 2016 2015 Metals inventory Raw ore $ 4,490 $ 4,234 Concentrate and in-process 55,888 43,727 Finished goods 24,473 32,618 Total metals inventory 84,851 80,579 Materials and supplies 20,334 21,493 Total inventory $ 105,185 $ 102,072

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
Anti-dilutive Shares Excluded From Computation of Diluted Earnings Per Share	The following table shows the shares that were excluded from the computation of diluted earnings per share, for the three months ended March 31, 2016 and 2015: Three Months Ended March 31, (In thousands) 2016 2015 Stock options 1 — Nonvested shares 309 — Contingently issuable 255 160 1.875% Convertible debentures, net of tax 22 — 1.75% Convertible debentures, net of tax 30,413 —
Reconciliation of Basic and Diluted Earnings Per Share	Reconciliations showing the computation of basic and diluted shares and the related impact on income for the three months ended March 31, 2015, is provided in the following table: Three Months Ended March 31, 2015 (In thousands, except per share amounts) Income (Numerator) Weighted Average Shares (Denominator) Per Share Amount Basic EPS Net income attributable to common stockholders $ 23,003 120,521 $ 0.19 Effect of Dilutive Securities Stock options — 3 Nonvested shares — 31 Contingently issuable shares — 154 1.875% Convertible debentures, net of tax — 95 1.75% Convertible debentures, net of tax 4,424 36,003 Diluted EPS Net income attributable to common stockholders and assumed conversions $ 27,427 156,807 $ 0.17

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2016
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, 2016 , and December 31, 2015 , consisted of the following: (In thousands) Fair Value Measurements At March 31, 2016 Total Level 1 Level 2 Level 3 Money market fund $ 91,721 $ 91,721 $ — $ — Mutual funds $ 911 $ 911 $ — $ — Investments Federal agency notes $ 248,164 $ — $ 248,164 $ — Commercial paper $ 32,494 $ — $ 32,494 $ — (In thousands) Fair Value Measurements At December 31, 2015 Total Level 1 Level 2 Level 3 Money market fund $ 54,761 $ 54,761 $ — $ — Mutual funds $ 743 $ 743 $ — $ — Investments Federal agency notes $ 284,757 $ — $ 284,757 $ — Commercial paper $ 31,672 $ — $ 31,672 $ —
Financial Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis	Assets and liabilities measured at fair value on a nonrecurring basis at March 31, 2016 , and December 31, 2015 , consisted of the following: (In thousands) Fair Value Measurements At March 31, 2016 Total Level 1 Level 2 Level 3 1.875% Convertible debentures $ 524 $ — $ 524 $ — 1.75% Convertible debentures $ 301,127 $ — $ 301,127 $ — (In thousands) Fair Value Measurements At December 31, 2015 Total Level 1 Level 2 Level 3 1.875% Convertible Debentures $ 524 $ — $ 524 $ — 1.75% Convertible Debentures $ 285,446 $ — $ 285,446 $ — Long-term investments $ 524 $ 524 $ — $ —

General (Details)

General (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Long-term debt and capital lease obligations	$ 259,661	$ 255,099
Accounting Standards Update 2015-03 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Long-term debt and capital lease obligations		255,100
Accounting Standards Update 2015-03 [Member] | Scenario, Previously Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Long-term debt and capital lease obligations		258,900
Accounting Standards Update 2015-03 [Member] | Scenario, Adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Long-term debt and capital lease obligations		$ 3,800

Sales (Details)

Sales (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Jul. 31, 2014	Mar. 31, 2016	Mar. 31, 2015
Sales Revenue, Goods, Net [Abstract]
Revenues from by-product sales		$ 5.1	$ 6.7
Term of refining agreement	5 years
Period after which refining agreement may be terminated	4 years
Customer Concentration Risk [Member] | Total revenues [Member] | Customer A [Member]
Revenue, Major Customer [Line Items]
Sales to significant customers (10% or more), percentage of total revenues		80.00%	74.00%

Noncontrolling Interest (Detail

Noncontrolling Interest (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Noncontrolling Interest [Abstract]
Noncontrolling interest, ownership percentage by noncontrolling owners	25.00%	25.00%
Purchase of noncontrolling interest, total consideration		$ 5,200
Purchase of noncontrolling interest, net of cash acquired		$ 1,000
Net income (loss) attributable to noncontrolling interest	$ 0		$ (115)

Derivative Instruments (Company

Derivative Instruments (Company's Outstanding Commodity Derivatives) (Details)	3 Months Ended
	Mar. 31, 2016oz$ / oz
Second Quarter 2016 [Member] | Platinum [Member]
Derivative [Line Items]
Ounces | oz	21,120
Average Price/Ounce | $ / oz	915
Second Quarter 2016 [Member] | Palladium [Member]
Derivative [Line Items]
Ounces | oz	39,807
Average Price/Ounce | $ / oz	532
Second Quarter 2016 [Member] | Rhodium [Member]
Derivative [Line Items]
Ounces | oz	4,608
Average Price/Ounce | $ / oz	653
Third Quarter 2016 [Member] | Platinum [Member]
Derivative [Line Items]
Ounces | oz	4,203
Average Price/Ounce | $ / oz	963
Third Quarter 2016 [Member] | Palladium [Member]
Derivative [Line Items]
Ounces | oz	4,072
Average Price/Ounce | $ / oz	548
Third Quarter 2016 [Member] | Rhodium [Member]
Derivative [Line Items]
Ounces | oz	1,536
Average Price/Ounce | $ / oz	684

Share Compensation Plans (Narra

Share Compensation Plans (Narrative) (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Apr. 30, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for issuance			11.6
Nonvested time-based shares [Member] | General and administrative expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 0.4	$ 0.3
Nonvested performance-based shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Nonvested performance-based shares [Member] | General and administrative expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 0.4	$ 0.1
2004 and 2012 Plans Combined [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available and reserved for grant	4.1
2012 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for issuance			5
2004 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for issuance			5.2
General Employee Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for issuance			1.4

Share Compensation Plans (Chang

Share Compensation Plans (Changes In The Company's Nonvested Shares) (Details)	3 Months Ended
	Mar. 31, 2016$ / sharesshares
Nonvested time-based shares [Member]
Nonvested Shares
Nonvested Shares, Beginning Balance | shares	186,655
Nonvested Shares, Granted | shares	206,974
Nonvested Shares, Vested | shares	(33,080)
Nonvested Shares, Forfeited | shares	0
Nonvested Shares, Ending Balance | shares	360,549
Weighted-Average Grant-Date Fair Value
Nonvested shares, Weighted-Average Grant-Date Fair Value, Beginning Balance (in usd per share) | $ / shares	$ 13.97
Nonvested shares, Weighted-Average Grant-Date Fair Value, Granted (in usd per share) | $ / shares	8.03
Nonvested shares, Weighted-Average Grant-Date Fair Value, Vested (in usd per share) | $ / shares	13.88
Nonvested shares, Weighted-Average Grant-Date Fair Value, Forfeited (in usd per share) | $ / shares	0
Nonvested shares, Weighted-Average Grant-Date Fair Value, Ending Balance (in usd per share) | $ / shares	$ 10.68
Nonvested performance-based shares [Member]
Nonvested Shares
Nonvested Shares, Beginning Balance | shares	379,277
Nonvested Shares, Granted | shares	186,285
Nonvested Shares, Vested | shares	0
Nonvested Shares, Forfeited | shares	0
Nonvested Shares, Ending Balance | shares	565,562
Weighted-Average Grant-Date Fair Value
Nonvested shares, Weighted-Average Grant-Date Fair Value, Beginning Balance (in usd per share) | $ / shares	$ 15.34
Nonvested shares, Weighted-Average Grant-Date Fair Value, Granted (in usd per share) | $ / shares	$ 11.45
Nonvested shares, Weighted-Average Grant-Date Fair Value, Vested (in usd per share) | $ / shares
Nonvested shares, Weighted-Average Grant-Date Fair Value, Forfeited (in usd per share) | $ / shares	$ 0
Nonvested shares, Weighted-Average Grant-Date Fair Value, Ending Balance (in usd per share) | $ / shares	$ 14.06

Share Compensation Plans (Compe

Share Compensation Plans (Compensation Expense of Nonvested Shares) (Details) $ in Thousands	Mar. 31, 2016USD ($)
Nonvested time-based shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining 2,016	$ 1,655
2,017	1,198
2,018	577
Total	3,430
Nonvested performance-based shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining 2,016	1,737
2,017	1,607
2,018	771
Total	$ 4,115

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Income tax benefit	$ 561	$ 6,043
Discrete income tax benefit, restructuring	3,400
Discrete income tax benefit, remeasurement of deferred state tax		8,600
Uncertain tax benefits	3,400
Interest and penalties accrued	100
Cash paid for income taxes	$ 300	$ 8,200

Debt and Capital Lease Obliga41

Debt and Capital Lease Obligations (Narrative) (Details)	Dec. 31, 2015USD ($)	Oct. 31, 2012USD ($)$ / sharesshares	Jan. 31, 2012USD ($)	Dec. 31, 2011USD ($)	Mar. 31, 2016USD ($)	Sep. 30, 2015USD ($)	Mar. 31, 2015USD ($)
Debt Instruments
Credit facility termination fees	$ 200,000
Capitalized Interest
Capitalized interest					$ 1,900,000		$ 1,300,000
1.75% Convertible Debentures [Member]
Debt Instruments
Debt, principal amount		$ 396,750,000
Stated interest rate	1.75%	1.75%			1.75%		1.75%
Convertible debt ratio		0.0604961
Debt conversion price (in usd per share) | $ / shares		$ 16.53
Embedded conversion feature, warrant, conversion ratio | shares		30.2481
Embedded conversion feature, warrant, conversion price (in usd per share) | $ / shares		$ 16.53
Effective term of debt instrument		7 years
Adjustments to equity, component of convertible debt treated as additional debt discount		$ 141,600,000
Debt issuance costs		$ 12,400,000
Debt and equity issuance costs amortization period		7 years
Principal amount of debt repurchased						$ 61,600,000
Cash paid to repurchase debt						59,400,000
Reduction of debt component						50,700,000
Reduction of debt discount						10,900,000
Write off of debt and equity issuance costs						700,000
Gain (loss) on extinguishment of debt, net						(4,200,000)
Effective interest rate		8.50%
Convertible debentures	$ 254,600,000				$ 259,100,000
Unamortized discount	76,754,000				72,409,000
Deferred debt issue costs	$ 3,821,000				$ 3,604,000
1.875% Convertible Debentures [Member]
Debt Instruments
Stated interest rate	1.875%				1.875%		1.875%
Principal amount of debt repurchased						1,700,000
Cash paid to repurchase debt						1,600,000
Gain (loss) on extinguishment of debt, net						$ 100,000
Convertible debentures	$ 500,000				$ 500,000
Credit Agreement [Member]
Debt Instruments
Debt issuance costs			$ 200,000	$ 1,100,000
Credit agreement			$ 125,000,000	$ 100,000,000
Credit Agreement [Member] | Minimum [Member]
Debt Instruments
Commitment fee on unutilized borrowing capacity				0.375%
Credit Agreement [Member] | Maximum [Member]
Debt Instruments
Commitment fee on unutilized borrowing capacity				0.50%

Debt and Capital Lease Obliga42

Debt and Capital Lease Obligations (Amortization of Debt Issuance Costs, Interest Expense and Cash Payments) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Oct. 31, 2012
Debt Instrument [Line Items]
Amortization of debt issuance costs	$ 217	$ 303
1.75% Convertible Debentures [Member]
Debt Instrument [Line Items]
Stated interest rate	1.75%	1.75%	1.75%	1.75%
Amortization of debt issuance costs	$ 217	$ 236
Interest expense, net of capitalized interest	3,993	5,001
Cash payments for interest	$ 0	$ 3,472
1.875% Convertible Debentures [Member]
Debt Instrument [Line Items]
Stated interest rate	1.875%	1.875%	1.875%
Interest expense, net of capitalized interest	$ 0	$ 0
Cash payments for interest	5	0
Credit Agreement [Member]
Debt Instrument [Line Items]
Amortization of debt issuance costs	0	67
Fees	$ 0	$ 251

Debt and Capital Lease Obliga43

Debt and Capital Lease Obligations (Current and Long-Term Debt Balances) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Oct. 31, 2012
Current
Capital Lease Obligation	$ 46	$ 580
Small Land Purchase	0	77
Total debt balances, Current	46	657
Long-Term
Capital Lease Obligation	0	0
Small Land Purchase	0	0
Total debt balances, Long-Term	$ 259,661	$ 255,099
1.75% Convertible Debentures [Member]
Debt Instrument [Line Items]
Stated interest rate	1.75%	1.75%	1.75%	1.75%
Current
Debt, Current	$ 0	$ 0
Long-Term
Aggregate principal	335,150	335,150
Debt discount	(72,409)	(76,754)
Deferred debt issue costs	(3,604)	(3,821)
Debt balance	$ 259,137	$ 254,575
1.875% Convertible Debentures [Member]
Debt Instrument [Line Items]
Stated interest rate	1.875%	1.875%	1.875%
Current
Debt, Current	$ 0	$ 0
Long-Term
Aggregate principal	$ 524	$ 524

Mineral Properties and Mine D44

Mineral Properties and Mine Development (Schedule of Mineral Properties) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Mining Properties, Mineral Rights and Mine Development [Member]
Property, Plant and Equipment [Line Items]
Mineral properties and mine development, gross	$ 1,050,569	$ 1,030,542
Accumulated depletion and amortization	(470,804)	(457,311)
Total mineral properties and mine development, net	579,765	573,231
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	713,614	697,781
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	224,475	220,281
Ontario, Canada [Member] | Mining Properties and Mineral Rights [Member] | Marathon Property [Member]
Property, Plant and Equipment [Line Items]
Mineral properties and mine development, gross	8,560	8,560
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 Equipment45

Property, Plant and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	$ 352,715		$ 351,792
Accumulated depreciation	(248,085)		(241,835)
Total property, plant, and equipment, net	104,630		109,957
Payments to Acquire Productive Assets [Abstract]
Non-cash capitalized interest and depreciation	(2,609)	$ (2,167)
Change in accounts payables for capital expenditures	185	1,694
Cash capital spend for the period	18,842	27,902
Machinery and equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	161,675		161,292
Buildings and structural components [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	173,795		173,580
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	11,740		11,740
Construction-in progress [Member] | Stillwater Mine [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	2,731		2,615
Construction-in progress [Member] | East Boulder Mine [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	266		435
Construction-in progress [Member] | Marathon Property [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	148		148
Construction-in progress [Member] | Processing Facilities and Other [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	2,360		$ 1,982
United States [Member]
Payments to Acquire Productive Assets [Abstract]
Capital expenditures	21,266	28,375
United States [Member] | Stillwater Mine [Member]
Payments to Acquire Productive Assets [Abstract]
Capital expenditures	16,770	21,013
United States [Member] | East Boulder Mine [Member]
Payments to Acquire Productive Assets [Abstract]
Capital expenditures	4,078	4,269
United States [Member] | Other Mine [Member]
Payments to Acquire Productive Assets [Abstract]
Capital expenditures	$ 418	$ 3,093

Segment Information (Narrative)

Segment Information (Narrative) (Details)	3 Months Ended
	Mar. 31, 2016SegmentBusiness_Component
Segment Reporting Information [Line Items]
Number of business segments | Segment	5
Mine Production [Member]
Segment Reporting Information [Line Items]
Number of business components | Business_Component	2

Segment Information (Financial

Segment Information (Financial Information Related To The Company's Business Segments) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Segment Reporting Information [Line Items]
Revenues	$ 133,638	$ 200,520
Depletion, depreciation and amortization	17,260	17,121
General and administrative expenses	8,297	8,345
Interest income	710	703
Interest expense	4,182	5,304
Income (loss) before income taxes	(10,491)	16,845
Capital expenditures	18,842	27,902
Total assets	1,275,239	1,409,043	$ 1,278,389
Mine Production [Member] | Business Segments [Member]
Segment Reporting Information [Line Items]
Revenues	85,802	125,738
Depletion, depreciation and amortization	17,069	16,869
General and administrative expenses	0	0
Interest income	0	0
Interest expense	0	0
Income (loss) before income taxes	1,291	28,828
Capital expenditures	18,435	25,548
Total assets	621,003	607,117
PGM Recycling [Member] | Business Segments [Member]
Segment Reporting Information [Line Items]
Revenues	47,736	74,682
Depletion, depreciation and amortization	191	252
General and administrative expenses	0	0
Interest income	293	403
Interest expense	0	0
Income (loss) before income taxes	1,793	2,127
Capital expenditures	10	59
Total assets	33,349	57,740
Canadian Properties [Member] | Business Segments [Member]
Segment Reporting Information [Line Items]
Revenues	0	0
Depletion, depreciation and amortization	0	0
General and administrative expenses	136	235
Interest income	0	3
Interest expense	0	0
Income (loss) before income taxes	(168)	(433)
Capital expenditures	0	0
Total assets	26,327	74,734
South American Properties [Member] | Business Segments [Member]
Segment Reporting Information [Line Items]
Revenues	0	0
Depletion, depreciation and amortization	0	0
General and administrative expenses	308	182
Interest income	1	14
Interest expense	0	0
Income (loss) before income taxes	(1,243)	(773)
Capital expenditures	0	0
Total assets	105,749	105,795
All Other [Member] | Business Segments [Member]
Segment Reporting Information [Line Items]
Revenues	100	100
Depletion, depreciation and amortization	0	0
General and administrative expenses	7,853	7,928
Interest income	416	283
Interest expense	4,182	5,304
Income (loss) before income taxes	(12,164)	(12,904)
Capital expenditures	397	2,295
Total assets	$ 488,811	$ 563,657

Investments (Narrative) (Detail

Investments (Narrative) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Investments pledged as collateral	$ 18.5	$ 18.5
Other Noncurrent Assets [Member]
Schedule of Available-for-sale Securities [Line Items]
Long-term investments	0.5	0
Letter of Credit [Member]
Schedule of Available-for-sale Securities [Line Items]
Undrawn letters of credit	$ 17.5	$ 17.5

Investments (Schedule of Availa

Investments (Schedule of Available-for-sale Securities) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	$ 281,336	$ 317,488
Gross unrealized gains	318	261
Gross unrealized losses	(85)	(577)
Fair value	281,569	317,172
Subtotal [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	280,680	317,006
Gross unrealized gains	63	0
Gross unrealized losses	(85)	(577)
Fair value	280,658	316,429
Federal agency notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	248,200	285,276
Gross unrealized gains	49	0
Gross unrealized losses	(85)	(519)
Fair value	248,164	284,757
Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	32,480	31,730
Gross unrealized gains	14	0
Gross unrealized losses	0	(58)
Fair value	32,494	31,672
Mutual funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	656	482
Gross unrealized gains	255	261
Gross unrealized losses	0	0
Fair value	$ 911	$ 743

Investments (Schedule of Maturi

Investments (Schedule of Maturities of Available-for-sale Securities) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	$ 281,336	$ 317,488
Fair value	281,569	317,172
Federal agency notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost, due in one year or less	172,432
Fair value, due in one year or less	172,433
Amortized cost, due after year one through two years	75,768
Fair value, due after year one through two years	75,731
Amortized cost	248,200	285,276
Fair value	248,164	284,757
Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost, due in one year or less	18,990
Fair value, due in one year or less	18,990
Amortized cost, due after year one through two years	13,490
Fair value, due after year one through two years	13,504
Amortized cost	32,480	31,730
Fair value	$ 32,494	$ 31,672

Inventories (Components Of Inve

Inventories (Components Of Inventories) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Metals inventory
Raw ore	$ 4,490	$ 4,234
Concentrate and in-process	55,888	43,727
Finished goods	24,473	32,618
Total metals inventory	84,851	80,579
Materials and supplies	20,334	21,493
Total inventory	$ 105,185	$ 102,072

Earnings Per Share (Anti-diluti

Earnings Per Share (Anti-dilutive Shares Excluded From Calculation of Diluted Earnings Per Share) (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Oct. 31, 2012
Stock options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of diluted earnings per share	1	0
Nonvested shares [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of diluted earnings per share	309	0
Contingently issuable [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of diluted earnings per share	255	160
1.875% Convertible Debentures [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stated interest rate	1.875%	1.875%	1.875%
1.875% Convertible Debentures [Member] | Convertible debentures [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of diluted earnings per share	22	0
1.75% Convertible Debentures [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stated interest rate	1.75%	1.75%	1.75%	1.75%
1.75% Convertible Debentures [Member] | Convertible debentures [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of diluted earnings per share	30,413	0

Earnings Per Share (Reconciliat

Earnings Per Share (Reconciliation of Basic and Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Oct. 31, 2012
Basic EPS
Net income attributable to common stockholders	$ (9,930)	$ 23,003
Weighted Average Shares (Denominator) (in shares)	121,071	120,521
Net income attributable to common stockholders (in usd per share)	$ (0.08)	$ 0.19
Effect of Dilutive Securities
Convertible debentures, net of tax		$ 4,424
Stock options (in shares)		3
Nonvested shares (in shares)		31
Contingently issuable shares (in shares)		154
Diluted EPS
Net income attributable to common stockholders and assumed conversions		$ 27,427
Weighted Average Shares (Denominator) (in shares)	121,071	156,807
Net income attributable to common stockholders and assumed conversions (in usd per share)	$ (0.08)	$ 0.17
1.875% Convertible Debentures [Member]
Effect of Dilutive Securities
Convertible debentures, net of tax (in shares)		95
Diluted EPS
Stated interest rate	1.875%	1.875%	1.875%
1.75% Convertible Debentures [Member]
Effect of Dilutive Securities
Convertible debentures, net of tax (in shares)		36,003
Diluted EPS
Stated interest rate	1.75%	1.75%	1.75%	1.75%

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details)	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Oct. 31, 2012
1.875% Convertible Debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	1.875%	1.875%	1.875%
1.75% Convertible Debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	1.75%	1.75%	1.75%	1.75%

Fair Value Measurements (Financ

Fair Value Measurements (Financial Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	$ 280,658	$ 316,429
Fair Value, Measurements, Recurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Money market fund	91,721	54,761
Mutual funds	911	743
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Money market fund	91,721	54,761
Mutual funds	911	743
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Money market fund	0	0
Mutual funds	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Money market fund	0	0
Mutual funds	0	0
Fair Value, Measurements, Recurring [Member] | Federal Agency Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	248,164	284,757
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	248,164	284,757
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	32,494	31,672
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	32,494	31,672
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 (Fina56

Fair Value Measurements (Financial Assets And Liabilities Measured At Fair Value On A Nonrecurring Basis) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Oct. 31, 2012
1.875% Convertible Debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	1.875%	1.875%	1.875%
1.75% Convertible Debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate	1.75%	1.75%	1.75%	1.75%
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term investments		$ 524
Fair Value, Measurements, Nonrecurring [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term investments		524
Fair Value, Measurements, Nonrecurring [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term investments		0
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term investments		0
Fair Value, Measurements, Nonrecurring [Member] | 1.875% Convertible Debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible debentures, fair value	$ 524	524
Fair Value, Measurements, Nonrecurring [Member] | 1.875% Convertible Debentures [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible debentures, fair value	0	0
Fair Value, Measurements, Nonrecurring [Member] | 1.875% Convertible Debentures [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible debentures, fair value	524	524
Fair Value, Measurements, Nonrecurring [Member] | 1.875% Convertible Debentures [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible debentures, fair value	0	0
Fair Value, Measurements, Nonrecurring [Member] | 1.75% Convertible Debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible debentures, fair value	301,127	285,446
Fair Value, Measurements, Nonrecurring [Member] | 1.75% Convertible Debentures [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible debentures, fair value	0	0
Fair Value, Measurements, Nonrecurring [Member] | 1.75% Convertible Debentures [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible debentures, fair value	301,127	285,446
Fair Value, Measurements, Nonrecurring [Member] | 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) (De

Related Parties (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2016	Dec. 31, 2015
Related Party Transaction [Line Items]
Noncontrolling interest, ownership percentage by noncontrolling owners		25.00%	25.00%
Affiliated Entity [Member]
Related Party Transaction [Line Items]
Revenue from related parties	$ 15.9