Molycorp (MCPIQ) 10-Q 8 Nov 13 2013 Q3 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	9 Months Ended
	Sep. 30, 2013	Nov. 06, 2013
Document And Entity Information [Abstract]	'	'
Entity Registrant Name	'Molycorp, Inc.	'
Entity Central Index Key	'0001489137	'
Document Type	'10-Q	'
Document Period End Date	30-Sep-13	'
Amendment Flag	'false	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	240,374,945
Document Fiscal Year Focus	'2013	'
Document Fiscal Period Focus	'Q3	'

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$173,914	$227,790
Trade accounts receivable, net (Note 4)	58,200	52,430
Inventory (Note 5)	183,441	287,376
Deferred charges (Note 15)	3,080	9,412
Deferred tax assets (Note 15)	8,478	9,789
Income tax receivable	20,296	25,087
Prepaid expenses and other current assets	25,660	21,794
Total current assets	473,069	633,678
Non-current assets:	'	'
Deposits (Note 6)	25,997	26,769
Property, plant and equipment, net (Note 7)	1,779,084	1,544,304
Inventory (Note 5)	24,325	26,096
Intangible assets, net (Note 9)	419,471	450,938
Investments	58,749	64,036
Goodwill (Note 9)	239,742	239,742
Other non-current assets	6,839	6,972
Total non-current assets	2,554,207	2,358,857
Total assets	3,027,276	2,992,535
Current liabilities:	'	'
Trade accounts payable	107,882	241,994
Accrued expenses (Note 12)	61,445	59,013
Income tax payable	1,708	15,267
Debt and capital lease obligations (Note 14)	16,673	39,604
Other current liabilities	6,689	3,539
Total current liabilities	194,397	359,417
Non-current liabilities:	'	'
Asset retirement obligation (Note 13)	14,084	18,586
Deferred tax liabilities (Note 15)	125,142	160,675
Debt and capital lease obligations (Note 14)	1,356,256	1,188,832
Derivative liability (Note 23)	6,819	7,816
Pension liabilities (Note 24)	3,431	3,292
Other non-current liabilities	2,052	2,659
Total non-current liabilities	1,507,784	1,381,860
Total liabilities	1,702,181	1,741,277
Commitments and contingencies (Note 19)	'	'
Stockholders’ equity:	'	'
Common stock, $0.001 par value; 350,000,000 shares authorized at September 30, 2013 (Note 16)	189	139
Preferred stock, $0.001 par value; 5,000,000 shares authorized at September 30, 2013 (Note 16)	2	2
Additional paid-in capital	1,946,742	1,691,429
Accumulated other comprehensive loss	-7,848	-9,433
Accumulated deficit	-646,163	-466,091
Total Molycorp stockholders’ equity	1,292,922	1,216,046
Noncontrolling interests	32,173	35,212
Total stockholders’ equity	1,325,095	1,251,258
Total liabilities and stockholders’ equity	$3,027,276	$2,992,535

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2013
Statement of Financial Position [Abstract]	'
Common stock, par value	$0.00
Common stock, authorized	350,000,000
Preferred stock, par value	$0.00
Preferred stock, authorized	5,000,000

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations and Comprehensive Loss (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Statement [Abstract]	'	'	'	'
Revenues	$149,066	$205,205	$430,580	$394,085
Costs of sales:	'	'	'	'
Costs excluding depreciation and amortization	-150,444	-183,227	-421,699	-336,654
Depreciation and amortization	-16,400	-10,612	-49,283	-19,065
Gross (loss) profit	-17,778	11,366	-40,402	38,366
Operating expenses:	'	'	'	'
Selling, general and administrative	-24,399	-31,349	-76,446	-78,583
Corporate development	-69	-1,073	-256	-19,379
Depreciation, amortization and accretion	-10,072	-9,584	-26,273	-12,188
Research and development	-5,565	-8,929	-18,476	-18,628
Impairment of goodwill and other long-lived assets	-1,118	'	-1,495	'
Operating loss	-59,001	-39,569	-163,348	-90,412
Other (expense) income:	'	'	'	'
Other income (expense)	-657	-57	1,430	-37,615
Foreign exchange (loss) gain, net	-234	1,910	1,044	724
Interest expense, net of capitalized interest	-16,289	-5,269	-42,807	-14,989
Total other expense	-17,180	-3,416	-40,333	-51,880
Loss before income taxes and equity earnings	-76,181	-42,985	-203,681	-142,292
Income tax benefit	12,902	28,956	38,922	58,442
Equity in results of affiliates	-2,334	-662	-8,690	-1,146
Loss from continuing operations	-65,613	-14,691	-173,449	-84,996
Loss from discontinued operations, net of tax	-4,186	-760	-5,190	-860
Net loss	-69,799	-15,451	-178,639	-85,856
Net income attributable to noncontrolling interest	-130	-3,440	-1,433	-4,120
Net loss attributable to Molycorp stockholders	-69,929	-18,891	-180,072	-89,976
Other comprehensive income:	'	'	'	'
Foreign currency translation adjustments	4,217	526	1,585	-1,165
Comprehensive loss	-65,582	-14,925	-177,054	-87,021
Comprehensive loss attributable to:	'	'	'	'
Molycorp stockholders	-65,452	-11,485	-175,621	-82,901
Noncontrolling interest	-130	-3,440	-1,433	-4,120
Comprehensive loss	($65,582)	($14,925)	($177,054)	($87,021)
Loss per share of common stock (Note 17):	'	'	'	'
Basic: Continuing operations (in dollars per share)	($0.41)	($0.18)	($1.12)	($0.97)
Basic: Discontinued operations (in dollars per share)	($0.02)	($0.01)	($0.03)	($0.01)
Basic (in dollars per share)	($0.43)	($0.19)	($1.16)	($0.97)
Diluted: Continuing operations (in dollars per share)	($0.41)	($0.18)	($1.12)	($0.97)
Diluted: Discontinued operations (in dollars per share)	($0.02)	($0.01)	($0.03)	($0.01)
Diluted (in dollars per share)	($0.43)	($0.19)	($1.16)	($0.97)

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Stockholders' Equity (USD $)

Molymet [Member]

Molymet [Member]

Molymet [Member]

Molymet [Member]

Molycorp Canada [Member]

Molycorp Canada [Member]

Molycorp Canada [Member]

Molycorp Canada [Member]

Molycorp Canada [Member]

Total Molycorp Stockholders' Equity

Common Stock [Member]

Series A Mandatory Convertible Preferred Stock [Member]

Additional Paid-In Capital

Accumulated Other Comprehensive Loss

Accumulated Deficit

Non Controlling Interests

Total

In Thousands, except Share data, unless otherwise specified

Total Molycorp Stockholders' Equity

Common Stock [Member]

Additional Paid-In Capital

Total Molycorp Stockholders' Equity

Common Stock [Member]

Additional Paid-In Capital

Non Controlling Interests

Balance at beginning of period at Dec. 31, 2011

'

'

'

'

'

'

'

'

'

$845,230

$84

$2

$838,547

($8,481)

$15,078

'

$845,230

Balance at beginning of period (in shares) at Dec. 31, 2011

'

'

'

'

'

'

'

'

'

'

83,896,043

2,070,000

'

'

'

'

'

Increase (Decrease) in Stockholders' Equity

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Stock-based compensation (Note 18)

'

'

'

'

'

'

'

'

'

3,764

'

'

3,764

'

'

'

3,764

Stock-based compensation (Note 18) (in shares)

'

'

'

'

'

'

'

'

'

'

-601

'

'

'

'

'

'

Component of convertible debt

'

'

'

'

'

'

'

'

'

71,801

'

'

71,801

'

'

'

71,801

Deferred taxes on component of convertible debt

'

'

'

'

'

'

'

'

'

-27,106

'

'

-27,106

'

'

'

-27,106

Issuance of shares for conversion of Debentures

'

'

'

'

'

'

'

'

'

1,421

'

'

1,421

'

'

'

1,421

Issuance of shares for conversion of Debentures (in shares)

'

'

'

'

'

'

'

'

'

'

99,723

'

'

'

'

'

'

Issuance of Primary Shares

390,093

12

390,081

390,093

'

'

'

'

'

132,130

14

'

132,116

'

'

'

132,130

Issuance of Primary Shares (in shares)

'

12,500,000

'

'

'

'

'

'

'

'

13,800,000

'

'

'

'

'

'

Issuance of shares for interest in Molycorp Canada

'

'

'

'

284,144

14

284,130

15,761

299,905

'

'

'

'

'

'

'

'

Issuance of shares for interest in Molycorp Canada (in shares)

'

'

'

'

'

13,862,286

'

'

'

'

'

'

'

'

'

'

'

Issuance of Borrowed Shares

'

'

'

'

'

'

'

'

'

25

14

'

11

'

'

'

25

Issuance of Borrowed Shares (in shares)

'

'

'

'

'

'

'

'

'

'

13,800,000

'

'

'

'

'

'

Net loss

'

'

'

'

'

'

'

'

'

-89,976

'

'

'

'

-89,976

4,120

-85,856

Preferred dividends

'

'

'

'

'

'

'

'

'

-8,539

'

'

-8,539

'

'

'

-8,539

Distribution to noncontrolling interests

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

-551

-551

Other comprehensive loss

'

'

'

'

'

'

'

'

'

-1,165

'

'

'

-1,165

'

'

-1,165

Fair value step-up of noncontrolling interest

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

34,982

34,982

Balance at end of period at Sep. 30, 2012

'

'

'

'

'

'

'

'

'

1,601,822

138

2

1,686,226

-9,646

-74,898

54,312

1,656,134

Balance at end of period (in shares) at Sep. 30, 2012

'

'

'

'

'

'

'

'

'

'

137,957,451

2,070,000

'

'

'

'

'

Balance at beginning of period at Dec. 31, 2012

'

'

'

'

'

'

'

'

'

1,216,046

139

2

1,691,429

-9,433

-466,091

35,212

1,251,258

Balance at beginning of period (in shares) at Dec. 31, 2012

'

'

'

'

'

'

'

'

'

'

138,773,538

2,070,000

'

'

'

'

'

Increase (Decrease) in Stockholders' Equity

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Stock-based compensation (Note 18)

'

'

'

'

'

'

'

'

'

2,399

'

'

2,399

'

'

'

2,399

Stock-based compensation (Note 18) (in shares)

'

'

'

'

'

'

'

'

'

'

43,847

'

'

'

'

'

'

Component of convertible debt

'

'

'

'

'

'

'

'

'

21,815

'

'

21,815

'

'

'

21,815

Deferred taxes on component of convertible debt

'

'

'

'

'

'

'

'

'

-8,508

'

'

-8,508

'

'

'

-8,508

Conversion of Exchangeable Shares (Note 16) (in shares)

'

'

'

'

'

'

'

'

'

'

12,971

'

'

'

'

'

'

Issuance of shares for conversion of Debentures

'

'

'

'

'

'

'

'

'

49

'

'

49

'

'

'

49

Issuance of shares for conversion of Debentures (in shares)

'

'

'

'

'

'

'

'

'

'

2,393

'

'

'

'

'

'

Issuance of Primary Shares

'

'

'

'

'

'

'

'

'

248,140

43

'

248,097

'

'

'

248,140

Issuance of Primary Shares (in shares)

'

'

'

'

'

'

'

'

'

'

43,125,000

'

'

'

'

'

'

Issuance of Borrowed Shares

'

'

'

'

'

'

'

'

'

7

7

'

'

'

'

'

7

Issuance of Borrowed Shares (in shares)

'

'

'

'

'

'

'

'

'

'

6,666,666

'

'

'

'

'

'

Net loss

'

'

'

'

'

'

'

'

'

-180,072

'

'

'

'

-180,072

1,433

-178,639

Preferred dividends

'

'

'

'

'

'

'

'

'

-8,539

'

'

-8,539

'

'

'

-8,539

Distribution to noncontrolling interests

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

-4,472

-4,472

Other comprehensive loss

'

'

'

'

'

'

'

'

'

1,585

'

'

'

1,585

'

'

1,585

Balance at end of period at Sep. 30, 2013

'

'

'

'

'

'

'

'

'

$1,292,922

$189

$2

$1,946,742

($7,848)

($646,163)

$32,173

$1,325,095

Balance at end of period (in shares) at Sep. 30, 2013

'

'

'

'

'

'

'

'

'

'

188,624,415

2,070,000

'

'

'

'

'

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:	'	'
Net loss	($178,639)	($85,856)
Adjustments to reconcile net loss to net cash from operating activities:	'	'
Depreciation, amortization and accretion	75,870	31,426
Deferred income tax benefit	-36,399	-35,179
Inventory write-downs	74,475	41,082
Release of inventory step-up value	5,650	26,428
Impairment of long-lived assets	4,949	'
Stock-based compensation expense	2,399	3,179
Allowance for doubtful accounts	'	2,500
Foreign exchange loss	-145	'
Equity in results of affiliates	8,690	1,146
Other operating adjustments	-1,651	167
Net change in operating assets and liabilities (Note 22)	-45,212	-32,081
Net cash used in operating activities	-90,013	-47,188
Cash flows from investing activities:	'	'
Cash paid in connection with acquisition, net of cash acquired	'	-591,011
Investment in joint ventures	-3,423	-28,130
Deposits	'	-516
Capital expenditures	-334,597	-644,683
Other investing activities	-364	4,953
Net cash used in investing activities	-338,384	-1,259,387
Cash flows from financing activities:	'	'
Capital contributions	'	390,225
Repayments of debt	-25,990	-228,431
Net proceeds from sale of common stock	248,150	132,471
Net proceeds from sale of Senior Notes	'	635,373
Issuance of Convertible Notes	165,600	395,712
Payments of preferred dividends	-8,539	-8,539
Proceeds from debt	'	9,456
Dividend paid to noncontrolling interests	-4,472	'
Other financing activities	-797	-3,331
Net cash provided by financing activities	373,952	1,322,936
Effect of exchange rate changes on cash	569	809
Net change in cash and cash equivalents	-53,876	17,170
Cash and cash equivalents at beginning of the period	227,790	418,855
Cash and cash equivalents at end of period	173,914	436,025
Non-cash financing activities and investing activities:	'	'
Change in accrued capital expenditures	-116,161	48,182
Fixed assets additions under capital lease	5,992	15,658
5.50% Convertible Notes, Net Of Discount, Due February 2018 [Member]	'	'
Cash flows from financing activities:	'	'
Issuance of Convertible Notes	165,600	'
6.00% Convertible Notes, Net Of Discount, Due September 2017 [Member]	'	'
Cash flows from financing activities:	'	'
Issuance of Convertible Notes	'	$395,712

Basis_Of_Presentation

Basis Of Presentation	9 Months Ended
	Sep. 30, 2013
Basis Of Presentation [Abstract]	'
Basis Of Presentation	'
	(1)Basis of Presentation
	Molycorp, Inc. (“Molycorp” or the “Company”) is one of the world's leading global rare earth companies, and the only one that operates a vertically integrated, global supply chain that combines a world-class rare earth resource with manufacturing facilities on three continents that can produce a wide variety of custom engineered, advanced rare earth materials from all of the lanthanide elements, plus yttrium. The Company's vertically integrated, global manufacturing supply chain is comprised of a workforce of approximately 2,650 scientists, engineers, chemists, technologists, and highly skilled workers in 27 locations across 11 countries. Molycorp's vertical integration allows it to operate multiple product supply chains, serve as a highly reliable supplier of advanced rare earth and rare metal materials, and provide price visibility to customers worldwide.
	The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and Regulation S-X promulgated under the Securities Exchange Act of 1934 (the “Exchange Act”). While the December 31, 2012 balance sheet information was derived from the Company’s audited financial statements, for interim periods, GAAP and Regulation S-X do not require all information and related disclosures that are required in the annual financial statements, and all disclosures required by GAAP for annual financial statements have not been included. Therefore, the accompanying unaudited condensed consolidated financial statements should be read in conjunction with Molycorp’s consolidated financial statements and related notes for the year ended December 31, 2012, included in Molycorp's Annual Report on Form 10-K filed on March 18, 2013, as amended on April 30, 2013 and as further amended on October 15, 2013, which includes the finalization of the Molycorp Canada purchase price allocation (see Note 9 and 11 below).
	The accompanying unaudited condensed consolidated financial statements reflect all adjustments, which are normal and recurring in nature, and which, in the opinion of management, are necessary for the fair presentation of Molycorp’s financial position, results of operations and cash flows at September 30, 2013, and for all periods presented. The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its consolidated subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
	The preparation of the financial statements, in accordance with GAAP, requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Management bases its estimates on the Company’s historical experience and on various other assumptions that are believed to be reasonable under the circumstances. Actual results may differ significantly from these estimates under different assumptions and conditions. Significant estimates made by management in the accompanying financial statements include the collectability of accounts receivable, the recoverability of inventory, the useful lives and recoverability of long-lived assets such as property, plant and equipment, intangible assets, goodwill and investments, capital leases, uncertain tax positions, the realizability of deferred tax assets, the fair values of assets acquired and liabilities assumed, including business combinations, and the adequacy of the Company’s asset retirement obligations.
	In addition, certain prior period amounts have been reclassified to conform to the current period presentation. Such reclassifications did not affect results of operations.
	The Company exited development stage status in the second quarter of 2012. At that time, its planned principal operations at the Molycorp Mountain Pass Rare Earth Facility (the "Molycorp Mountain Pass facility") had effectively commenced with the transition to production from recently-mined rare earth ore, and the Company's revenues began to significantly increase as a result of the acquisition of Molycorp Canada (see Note 11).

Liquidity_And_Capital_Requirem

Liquidity And Capital Requirements	9 Months Ended
	Sep. 30, 2013
Liquidity And Capital Requirements [Abstract]	'
Liquidity And Capital Requirements	'
	(2)Liquidity and Capital Requirements
	Total capital expenditures for the modernization and expansion efforts and certain other capital projects at the Molycorp Mountain Pass facility are expected to total approximately $1.55 billion. This projection includes certain expenditures that are expected to be deferred until 2014 and 2015, including discretionary expenditures required only to expand production beyond the Molycorp Mountain Pass facility's design capacity of 19,050 metric tons ("mt") of separated rare earth oxides ("REO"), if and when market demand, product pricing, capital availability and financial returns will justify such production. Of the $1.55 billion projected capital expenditures, the Company had spent approximately $1.37 billion on a cash basis through September 30, 2013, excluding capitalized interest.
	As of September 30, 2013, the Company had available cash balances of $173.9 million and estimates cash expenditures totaling approximately $60 million through December 31, 2013, approximately $40 million in 2014 and approximately $80 million in 2015 to fund the remaining capital expenditures for the modernization and expansion efforts and certain other capital expenditures at the Molycorp Mountain Pass facility. Additionally, the Company expects to spend approximately $5 million to $8 million on other maintenance and expansion capital expenditures across all operating segments during the fourth quarter of 2013, some of which is discretionary.
	Other cash requirements for the remainder of 2013 include the final payment of approximately $6.0 million to the noncontrolling shareholder of the Company's majority owned Jiangyin Jia Hua Advanced Material Resources Co. Ltd. facility in Jiangyin, China, and preferred stock dividend payments of approximately $2.8 million, if and after they are declared by the Board of Directors of the Company to be paid in cash.
	Given the combination of continued commissioning and start-up activities at the Molycorp Mountain Pass facility, and the soft pricing environment of rare earth elements ("REEs"), the Company anticipates significantly lower than previously expected revenues and cash flow from operations through the remainder of 2013. As a result, and as further detailed in Note 28 below, the Company completed an additional financing in October 2013 to secure funding for its anticipated cash needs.
	The Company expects to use its cash balances of $173.9 million as of September 30, 2013, the net proceeds of approximately $247.5 million from the common stock offering completed in October 2013, as well as cash generated from operations, to fund current needs for capital expenditures and other cash requirements, including, without limitation, capital expenditures at the Molycorp Mountain Pass facility. While the Company's cash balances as of September 30, 2013 and the net proceeds from the common stock offering completed in October 2013 are expected to be sufficient to satisfy its cash needs, the amount of the Company's funding requirements continues to be dependent on (i) its cost estimates for capital expenditures being accurate, (ii) its ability to ramp up run rates at its Molycorp Mountain Pass facility pursuant to its expectations without further delays and the successful commissioning of its chloralkali plant and its multi-stage cracking unit, which is expected to reduce the Company's cash costs of production, (iii) market conditions improving over what the Company is currently experiencing and that it is able to sell all its production at such prices, (iv) its ability to sell its production of REO (in particular, including its ability to sell its cerium through market acceptance of SorbX™ or otherwise) and (v) the absence of payments on current and future contingent liabilities. If these assumptions prove inaccurate, the Company's estimates could prove incorrect and it may need additional financing.
	As part of its cash management procedures, the Company continues to pursue other sources of liquidity, including potential proceeds from revolving credit facilities, and lease and loan financing for certain equipment, although the Company does not have any firm commitments for such revolving credit facilities and its success in securing equipment financing has been limited.

Segment_Information

Segment Information	9 Months Ended
	Sep. 30, 2013
Segment Information [Abstract]	'
Segment Information	'
	(3)Segment Information
	In the third quarter of 2012, management reorganized the Company's operations into four new reportable segments to better reflect its primary activities as a global producer of custom engineered, advanced rare earth materials: Resources; Chemicals and Oxides; Magnetic Materials and Alloys; and Rare Metals. The new composition of the Company's reportable segments is based on a combination of product lines and technologies aligned with its current strategy.
	The Resources segment includes the Company's operations at its Molycorp Mountain Pass facility where it conducts rare earth minerals extraction to produce: purified unseparated rare earth concentrates; REO, including lanthanum, cerium and neodymium/praseodymium; heavy rare earth concentrates, which include samarium, europium, gadolinium (“SEG”), terbium, dysprosium, and others; and SorbX™, a line of proprietary rare earth-based water treatment products.
	The Chemicals and Oxides segment includes: production of REO at the Company's operations in Sillamäe, Estonia ("Molycorp Silmet"); heavy rare earth oxides from the Company's facilities in Jiangyin, Jiangsu Province, China; and production of REO, salts of REEs, zirconium-based engineered materials and mixed rare earth/zirconium oxides from the Company's facilities in Zibo, Shandong Province, China. Rare earths products and zirconium-based engineered products are primarily supplied to the automotive catalyst, electronics, ceramic, clean technology and glass industries.
	The Magnetic Materials and Alloys segment includes: the production of neodymium-iron-boron ("NdFeB") magnet powders ("Neo Powders™") through Molycorp's wholly-owned manufacturing facilities in Tianjin, China and Korat, Thailand, under the Molycorp Magnequench brand. Neo Powders™ are used to make bonded magnets for a variety of electronic and mechanical products such as micro motors, precision motors, sensors and other applications requiring high levels of magnetic strength, flexibility, small size and reduced weight. This reporting segment also includes manufacturing of neodymium and samarium magnet alloys, other specialty alloy products and rare earth metals at Molycorp Metals and Alloys ("MMA") in Tolleson, Arizona.
	The Rare Metals segment comprises: Molycorp's production of gallium, indium, tantalum and rhenium from its operations in Quapaw, Oklahoma; Blanding, Utah; Peterborough, Ontario; Sagard, Germany; and Hyeongok Industrial Zone in South Korea. This operating segment also includes tantalum and niobium from the Company's operations in Sillamäe, Estonia. Rare metals are primarily used in the wireless, light-emitting diode, flat panel display, turbine, solar and catalyst industries. In July 2013, the Company committed to a plan to discontinue operations at its Napanee, Ontario – Canada facility by the end of fiscal 2013 due to a declining demand for rhenium combined with unfavorable operating costs in this particular recycling sector. Therefore, the operating results of the Napanee facility were included in discontinued operations for the three and nine months ended September 30, 2013, and the prior period presentation of financial data for the Rare Metals segment has been revised for comparative purposes. See Note 26 below for further details.
	The asset retirement obligation is recognized only within the Resources segment. In addition, the annual profit earned from the Estonian operations is not taxed in Estonia. In accordance with the Estonian Income Tax Act, only the distribution of annual profit is subject to income tax in Estonia. Intersegment sales and transfers are based on similar arms-length transactions with third parties at the time of the sale.
					Magnetic
				Chemicals and	Materials and		Corporate and		Total Molycorp,
	Three months ended September 30, 2013		Resources	Oxides	Alloys	Rare Metals	other(a)	Eliminations(b)	Inc.
	Revenues:		(In thousands of dollars)
	External		4,655	50,791	72,626	20,994		—	149,066
	Intersegment		8,858	7,174	—	—		-16,032	—
	Total revenues		13,513	57,965	72,626	20,994		-16,032	149,066
	Depreciation, amortization and accretion		-10,853	-5,960	-7,458	-2,144	-57	—	-26,472
	Operating (loss) income		-55,526	-1,399	11,062	-3,055	-10,806	723	-59,001
	(Loss) income before income taxes and equity earnings		-56,139	-1,527	39,291	-4,807	-53,722	723	-76,181
	Total assets at September 30, 2013		1,880,127	567,207	621,127	100,794	1,329,485	-1,471,464	3,027,276
	Capital expenditures (c)		57,637	1,573	1,457	1,946	77	—	62,690
					Magnetic
				Chemicals and	Materials and		Corporate and		Total Molycorp,
	Three months ended September 30, 2012		Resources	Oxides	Alloys	Rare Metals	other(a)	Eliminations(b)	Inc.
	Revenues:		(In thousands of dollars)
	External		17,150	87,820	74,789	25,446		—	205,205
	Intersegment		3,745	11,559	—	—		-15,304	—
	Total revenues		20,895	99,379	74,789	25,446		-15,304	205,205
	Depreciation, amortization and accretion		-4,035	-5,685	-8,857	-1,576	-43	—	-20,196
	Operating (loss) income		-23,966	2,149	1,419	-3,014	-16,526	369	-39,569
	(Loss) income before income taxes and equity earnings		-25,506	1,201	1,215	-3,052	-17,212	369	-42,985
	Capital expenditures (c)		187,611	2,597	1,432	2,837	1,387	—	195,864
					Magnetic
				Chemicals and	Materials and		Corporate and		Total Molycorp,
	Nine months ended September 30, 2013		Resources	Oxides	Alloys	Rare Metals	other(a) (d)	Eliminations(b)	Inc.
	Revenues:		(In thousands of dollars)
	External		30,235	135,180	193,417	71,748		—	430,580
	Intersegment		18,168	28,476	—	—		-46,644	—
	Total revenues		48,403	163,656	193,417	71,748		-46,644	430,580
	Depreciation, amortization and accretion		-31,536	-17,087	-20,360	-6,402	-171	—	-75,556
	Operating (loss) income		-136,055	-19,879	28,463	-2,455	-32,321	-1,101	-163,348
	(Loss) income before income taxes and equity earnings		-135,047	-18,438	67,089	57	-116,241	-1,101	-203,681
	Capital expenditures (c)		205,669	5,672	2,910	5,595	244	—	220,090
					Magnetic
				Chemicals and	Materials and		Corporate and		Total Molycorp,
	Nine months ended September 30, 2012		Resources	Oxides	Alloys	Rare Metals	other(a) (d)	Eliminations(b)	Inc.
	Revenues:
	External		78,162	134,158	125,277	56,488		—	394,085
	Intersegment		5,977	15,496	—	—		-21,473	—
	Total revenues		84,139	149,654	125,277	56,488		-21,473	394,085
	Depreciation, amortization and accretion		-8,743	-7,419	-10,810	-4,185	-96	—	-31,253
	Operating income (loss)		-23,594	-21,863	-1,544	-1,087	-66,804	24,480	-90,412
	(Loss) income before income taxes and equity earnings		-25,044	-23,663	-2,381	-2,138	-113,546	24,480	-142,292
	Capital expenditures (c)		675,836	6,615	1,612	6,955	1,733	—	692,751
	(a)	Corporate loss before income taxes and equity earnings includes business development costs, personnel and related costs, including stock-based compensation expense, accounting and legal fees, occupancy expense, information technology costs and interest expense. Total corporate assets is comprised primarily of cash and cash equivalents.
	(b)	The net elimination in operating results includes costs of sales eliminations of $16,755 and $45,543 for the three and nine months ended September 30, 2013, respectively; $15,673 and $45,952 for the three and nine months ended September 30, 2012, respectively. Costs of sales eliminations consist of intercompany gross profits as well as eliminations of lower of cost or market adjustments related to intercompany inventory. The total assets elimination is comprised primarily of intercompany investments and intercompany accounts receivable and profits in inventory.
	(c)	On an accrual basis excluding capitalized interest.
	(d)	The Corporate segment included severance charges of $2,100 for the nine months ended September 30, 2013. See Note 24 for details.

Trade_Accounts_Receivable

Trade Accounts Receivable	9 Months Ended
	Sep. 30, 2013
Trade Accounts Receivable [Abstract]	'
Trade Accounts Receivable	'
	(4)Trade Accounts Receivable
	Trade accounts receivable are recorded at the invoiced amount and do not bear interest. The Company reviews the need for an allowance for doubtful accounts quarterly based on historical experience with each customer and the specifics of each arrangement. At September 30, 2013 and December 31, 2012, the allowance for doubtful accounts was $2.6 million.

Inventory

Inventory	9 Months Ended
	Sep. 30, 2013
Inventory [Abstract]	'
Inventory	'
	(5)Inventory
	At September 30, 2013 and December 31, 2012, inventory consisted of the following:
		September 30,		December 31,
		2013		2012
	Current:	(In thousands)
	Concentrate stockpiles	$	660	$	6,393
	Raw materials		58,269		95,248
	Work-in-process		41,797		55,229
	Finished goods		61,601		114,903
	Materials and supplies		21,114		15,603
	Total current	$	183,441	$	287,376
	Long-term:
	Concentrate stockpiles	$	4	$	4
	Raw materials		24,321		26,092
	Total long-term	$	24,325	$	26,096
	Assessment of normal production levels
	The Company performs an assessment of normal production levels on a quarterly basis. As a result, it expenses a portion of its production costs that, assuming the Company had been operating at normal production ranges, would have been allocated to inventory. For the three months ended September 30, 2013 and 2012, the Company excluded from inventory, and expensed, $18.2 million and $3.9 million, respectively, and $65.7 million and $9.8 million for the nine months ended September 30, 2013 and 2012, respectively.
	Write-downs of inventory
	As a result of production or purchase costs in excess of net realizable value, the Company recognized write-downs of finished goods and work-in-process inventory of $19.6 million and $15.0 million for the three months ended September 30, 2013 and 2012, respectively, and $60.7 million and $41.1 million for the nine months ended September 30, 2013 and 2012, respectively. In addition, due to slow moving inventory and adjustments to estimated REO quantities, the Company recognized write-downs of stockpile inventory totaling $6.9 million and zero for the three months ended September 30, 2013 and 2012, respectively, and $13.7 million and zero for the nine months ended September 30, 2013 and 2012, respectively. The level within the fair value hierarchy in which the write-downs of inventory are included is the significant other observable inputs—Level 2.
	Subject to certain exceptions, substantially all of the property and assets of the Company are pledged as collateral for some of the Company's indebtedness, as further discussed in Note 14.

Deposits

Deposits	9 Months Ended
	Sep. 30, 2013
Deposits [Abstract]	'
Deposits	'
	(6)Deposits
	The Company had $26.0 million and $26.8 million in deposits reported as non-current assets at September 30, 2013 and December 31, 2012, respectively. The deposits at September 30, 2013 consisted of $20.5 million under an escrow arrangement for the Company’s facilities agreement with Kern River Gas Transmission Company, $2.5 million related to the Company’s construction insurance program, and $3.0 million comprised primarily of collateral placed against the surety bonds issued to California state and regional agencies for the closure and reclamation obligations at the Molycorp Mountain Pass facility.

Property_Plant_And_Equipment_N

Property, Plant And Equipment, Net	9 Months Ended
	Sep. 30, 2013
Property, Plant And Equipment, Net [Abstract]	'
Property, Plant And Equipment, Net	'
	(7)Property, Plant and Equipment, net
	The Company capitalized expenditures of $83.0 million and $218.1 million for the three months ended September 30, 2013 and 2012, respectively, and $281.3 million and $728.2 million for the nine months ended September 30, 2013 and 2012, respectively. The majority of these capital expenditures related to the expansion and modernization efforts, and certain other capital projects, at the Molycorp Mountain Pass facility. These amounts include capitalized interest of $20.3 million and $22.2 million for the three months ended September 30, 2013 and 2012, respectively, and $61.2 million and $35.5 million for the nine months ended September 30, 2013 and 2012, respectively.
	At September 30, 2013 and December 31, 2012, property, plant and equipment consisted of the following
		September 30,		December 31,
		2013		2012
		(In thousands)
	Land	$	12,678	$	12,475
	Land improvements		68,903		63,269
	Buildings and improvements		404,436		237,379
	Plant and equipment		290,678		194,934
	Vehicles		2,942		2,842
	Computer software		12,254		9,528
	Furniture and fixtures		1,044		1,116
	Construction in progress (a)		1,010,173		1,011,541
	Natural gas delivery facility under capital lease		15,658		15,658
	Mining equipment under capital lease		5,992		—
	Mineral properties		24,115		24,327
	Exploration rights		16,170		16,166
	Property, plant and equipment at cost		1,865,043		1,589,235
	Less accumulated depreciation		-85,959		-44,931
	Property, plant and equipment, net	$	1,779,084	$	1,544,304
	(a)	Represents costs incurred at the Molycorp Mountain Pass facility and all other capital projects. See Note 2.
	The amortization of assets recorded under capital leases is included with depreciation expense in the condensed consolidated statements of operations and comprehensive income.
	Subject to certain exceptions, substantially all of the property and assets of the Company are pledged as collateral for some of the Company's indebtedness, as further discussed in Note 14.

Mineral_Properties_Development

Mineral Properties, Development Costs And Exploration Rights	9 Months Ended
	Sep. 30, 2013
Mineral Properties, Development Costs And Exploration Rights [Abstract]	'
Mineral Properties, Development Costs And Exploration Rights	'
	(8)Mineral Properties, Development Costs and Exploration Rights
	Mineral properties and development costs, which are referred to collectively as mineral properties, include acquisition costs, drilling costs, and the cost of other development work associated with the Molycorp Mountain Pass facility, all of which are capitalized. The Company began depleting mineral properties in 2012 using the units of production method over estimated proven and probable reserves that were stated in an updated reserve report dated January 4, 2012. For the nine months ended September 30, 2013, the Company capitalized $0.2 million of depletion costs in work-in-process inventory related to the reserves that were mined and crushed. During the corresponding prior period, the Company capitalized a nominal amount of depletion costs.
	Exploration rights represent acquired rights to explore properties that are believed to potentially contain mineral deposits.

Goodwill_And_Other_Intangible_

Goodwill And Other Intangible Assets	9 Months Ended
	Sep. 30, 2013
Goodwill And Other Intangible Assets [Abstract]	'
Goodwill And Other Intangible Assets	'
	(9)Goodwill and Other Intangible Assets
	In connection with the final allocation of the consideration transferred to the net assets of Molycorp Canada that was completed in the second quarter of 2013, the Company increased the initial carrying value of goodwill, but recognized additional goodwill impairment of $31.6 million that completely offset the incremental goodwill. The additional goodwill impairment was recognized retroactively in the fourth quarter of 2012.
						Additional		September 30,
		December 31, 2012				impairment		2013
		Reported		Adjustment
		(In thousands)
	Chemicals and Oxides	$	125,229	$	16,132	$	-16,132	$	125,229
	Magnetic Materials and Alloys		102,808		16,716		-16,716		102,808
	Rare Metals		11,705		-1,232		1,232		11,705
	Total	$	239,742	$	31,616	$	-31,616	$	239,742
	At September 30, 2013 and December 31, 2012, other intangible assets consisted of the following:
		Customer		Rare earth						Land use
		relationships		quotas		Patents		Trade names		rights		Other		Total
	Gross carrying amount	(In thousands)
	At December 31, 2012	$	344,774		78,300		33,252	$	15,586		3,568		4,420	$	479,900
	Additions		48												48
	Foreign currency translation adjustment		-262		—		—		—		—		—		-262
	At September 30, 2013	$	344,560	$	78,300	$	33,252	$	15,586	$	3,568	$	4,420	$	479,686
	Amortization
	At December 31, 2012	$	14,095		4,035		9,365	$	1,152		66		249	$	28,962
	Adjustments		-269		—		—		-873		—		—		-1,142
	Amortization		16,395		5,238		10,131		49		121		461		32,395
	At September 30, 2013		30,221		9,273		19,496		328		187		710		60,215
	Net book value	$	314,339	$	69,027	$	13,756	$	15,258	$	3,381	$	3,710	$	419,471
	At September 30, 2013, trade names included indefinite-lived intangible assets with a gross carrying amount of $14.8 million. During the first quarter of 2013, the Company reversed an immaterial prior period amortization related to these assets as part of certain measurement period adjustments associated with the acquisition of Molycorp Canada.
	Total amortization expense of all other intangible assets during the nine months ended September 30, 2012 was $2.7 million.

Investments

Investments	9 Months Ended
	Sep. 30, 2013
Investments [Abstract]	'
Investments	'
	(10)Investments
	Boulder Wind Power, Inc.
	On September 13, 2011, the Company invested $20.0 million into Boulder Wind Power, Inc. Series B convertible preferred stock, which is accounted for at cost. At September 30, 2013, the fair value of this investment was not estimated as there were no identified events or changes in circumstances that may have had a significant adverse effect on the fair value of the investment.
	Intermetallics Japan Joint Venture
	In January 2012, Molycorp, Daido Steel Co., Ltd. (“Daido”) and Mitsubishi Corporation (“Mitsubishi”) entered into a definitive shareholders agreement for the purpose of funding a new joint venture, Intermetallics Japan ("IMJ"), to manufacture sintered NdFeB permanent rare earth magnets. The capital contribution ratio of IMJ is 30.0% by Molycorp, 35.5% by Daido and 34.5% by Mitsubishi.
	During the first quarter of 2013, Molycorp contributed $3.4 million in cash to complete the acquisition of its proportional ownership in IMJ. Total contributions by Molycorp to IMJ from the signing of the definitive shareholders agreement were $31.1 million.
	Molycorp accounts for this investment under the equity method because it has the ability to exercise significant influence over the operating and financial policies of IMJ, as evidenced by Molycorp’s ownership share and its proportional voting rights and representation in the Board of Directors of IMJ. The condensed consolidated statements of operations and comprehensive income for the three months ended September 30, 2013 and 2012 include a loss of $1.6 million and $0.2 million, respectively, associated with this equity method interest. For the nine months ended September 30, 2013 and 2012, the loss from the investment in IMJ was $5.2 million and $0.8 million, respectively.
	Molycorp Canada Investments
	As a result of the acquisition of Molycorp Canada in June 2012, Molycorp acquired the following investments:
	·	25% ownership interest in Ganzhou Keli Rare Earth New Material Co., Ltd. (“Keli”), a company that converts REO into metals for use in Neo Powders™.  The purchase allocation attributable to this investment at the time of the acquisition was $12.2 million. Molycorp accounts for this ownership interest under the equity method because it has the ability to exercise significant influence over the operating and financial policies of Keli, as evidenced by Molycorp’s ownership share and its proportional voting rights. The condensed consolidated statements of operations and comprehensive income include a loss associated with this equity method ownership interest of $0.7 million and $3.1 million for the three and nine months ended September 30, 2013, and a gain of $0.3 million for the period from June 12, 2012 to September 30, 2012.
	·	33% ownership interest in Toda Magnequench Magnetic Materials Co. Ltd. (“TMT”), a company that produces rare earth magnetic compounds with Neo Powders™ supplied by Magnequench (Tianjin) Company Limited in its normal course of business. The purchase allocation attributable to this investment at the time of the acquisition was $1.6 million. Molycorp accounts for this ownership interest under the equity method because it has the ability to exercise significant influence over the operating and financial policies of TMT, as evidenced by Molycorp’s ownership share and its proportional voting rights. The results of operations associated with this equity method investment were nominal in the current and prior year interim periods.
	·	50% ownership interest in Ingal Stade GmbH (“Ingal Stade”), a joint venture facility in Stade, Germany, which extracts gallium metal from alumina smelter bayer liquor with purity level of 5N (99.999%) or higher. The purchase allocation attributable to this investment at the time of the acquisition was $4.9 million. Molycorp accounts for this ownership interest under the equity method because it has the ability to exercise significant influence over the operating and financial policies of Ingal Stade, as evidenced by Molycorp’s ownership share and its proportional voting rights. The condensed consolidated statements of operations and comprehensive income include a loss associated with this equity method ownership interest of  $0.3 million for the nine months ended September 30, 2013. The results of operations associated with this equity method investment were nominal in the current quarter and prior year interim periods.
	·	19.5% ownership interest in Atlantic Metals & Alloys, LLC, a company that provides refining services for residues and scrap of the rare and platinum group metals. The purchase allocation attributable to this investment at the time of the acquisition was $1.4 million. Molycorp accounts for this ownership interest under the cost method. At September 30, 2013, the fair value of this investment was not estimated as there were no identified events or changes in circumstances that may have had a significant adverse effect on the fair value of the investment.
	·	7% ownership interest in Vive Crop Protection, a company that specializes in the formulation of active ingredients used in crop protection. The purchase allocation attributable to this investment at the time of the acquisition was $0.9 million. Molycorp accounts for this ownership interest under the cost method. At September 30, 2013, the fair value of this investment was not estimated as there were no identified events or changes in circumstances that may have had a significant adverse effect on the fair value of the investment.

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2013
Acquisitions [Abstract]	'
Acquisitions	'
	(11)Acquisitions
	Molycorp Canada
	On June 11, 2012, Molycorp completed the acquisition of all of the outstanding equity of Molycorp Canada's predecessor company pursuant to the terms of an arrangement agreement (the "Arrangement Agreement") for an aggregate purchase price of approximately $1,192.3 million. Pursuant to the Arrangement Agreement, Molycorp Canada's former shareholders elected to receive: (a) cash consideration equal to Canadian dollars ("Cdn") $11.30 per share of Molycorp Canada's predecessor company's common stock; or (b) share consideration of 0.4242 shares of Molycorp common stock or 0.4242 shares (the "Exchangeable Shares") issued by MCP Exchangeco Inc., Molycorp's wholly-owned Canadian subsidiary, which are exchangeable for shares of Molycorp's common stock on a one-for-one basis, per each share of Molycorp Canada's predecessor company's common stock; or (c) a combination of cash and shares of Molycorp common stock or Exchangeable Shares, all subject to the proration mechanics set forth in the Arrangement Agreement.
	The consideration paid to Molycorp Canada's former shareholders was comprised of approximately $908.2 million in cash, exclusive of realized losses on the contingent forward contract to purchase $870.0 million Canadian dollars, accounted for as a separate transaction apart from the business combination, as further discussed in Note 23. Additionally, 13,545,426 shares of Molycorp common stock and 507,203 Exchangeable Shares were issued and collectively valued at $284.1 million based on the closing price of the Company's common stock on the acquisition date in accordance with the relevant accounting guidance. The Exchangeable Shares have no par value.
	A preliminary allocation of the consideration transferred to the net assets of Molycorp Canada was made as of June 11, 2012. During the second quarter of 2013, the Company further adjusted the preliminary values assigned to certain assets and liabilities of Molycorp Canada in order to reflect additional information obtained since June 11, 2012. As a result of the additional goodwill recognized during the final allocation of the consideration transferred to the net assets of Molycorp Canada, the goodwill impairment the Company recognized in the fourth quarter of 2012 has increased by $31.6 million to $287.9 million. The measurement period adjustments described in the table below have been reflected in the opening balance sheet; however, since these adjustments did not have a significant impact on the Company's condensed consolidated statements of operations and comprehensive income or cash flows in any period, those statements were not retrospectively adjusted.
	The following table summarizes the determination of the fair value of identifiable assets acquired and liabilities assumed in the Molycorp Canada acquisition:
		Preliminary
		Allocation of
		Consideration
		Transferred as of		Measurement		Final Allocation of
		December 31,		Period		Consideration
		2012		Adjustments		Transferred
	Purchase consideration:	(In thousands)
	Cash consideration	$	908,181			$	908,181
	Fair value of Molycorp common stock and Exchangeable Shares issued		284,144				284,144
	Total purchase consideration	$	1,192,325			$	1,192,325
	Estimated fair values of the assets and liabilities acquired:
	Cash and cash equivalents	$	317,169	$	—	$	317,169
	Restricted cash		4,951		—		4,951
	Accounts receivable		101,470		—		101,470
	Inventory		250,989		—		250,989
	Prepaid expenses and other current assets		26,893		—		26,893
	Property, plant and equipment		75,745		—		75,745
	Investments		21,019		-1,091		19,928
	Intangibles		482,234		—		482,234
	Deferred tax charges		13,435		—		13,435
	Deferred tax assets		11,473		-1,423		10,050
	Goodwill		494,809		31,616		526,425
	Other non-current assets		4,367		—		4,367
	Accounts payable and accrued expenses		-138,576		—		-138,576
	Debt		-255,338		—		-255,338
	Other current liabilities		-33,990		—		-33,990
	Deferred tax liabilities		-154,309		5,880		-148,429
	Other non-current liabilities		-14,255		—		-14,255
	Non-controlling interests		-15,761		-34,982		-50,743
	Total purchase consideration	$	1,192,325	$	—	$	1,192,325
	Goodwill associated with the acquisition of Molycorp Canada arose primarily because of Molycorp Canada's proven leadership in the development, processing, and distribution of technically advanced rare earth products; greater exposure to the world’s largest and fastest-growing rare earths consuming market, China; deferred tax liabilities; and expected synergies that do not qualify for separate recognition. The goodwill is not amortized and is not deductible for tax purposes. During the fourth quarter of 2012, after giving effect to the final purchase price adjustments as noted above, the Company recognized a goodwill impairment of $287.9 million, and an impairment of patents recorded under the Magnetic Materials and Alloys segment of $6.0 million.
	The revenues, earnings and earnings per share of the combined entity had the acquisition date been January 1, 2012, were as follows:
						Net loss
						Attributable To Molycorp.
						Attributable To
	(In thousands, except per share amounts)	Revenues		Net Loss		Molycorp		Loss per share
	Unaudited pro forma January 1, 2012 to September 30, 2012 (combined entity)	$	729,469	$	-74,229	$	-82,056	$	-0.77
	The unaudited pro forma amounts are not necessarily indicative of the operating results that would have occurred if the acquisition of Molycorp Canada had taken place on January 1, 2012. The unaudited pro forma revenues, earnings and earnings per share of the combined entity above are adjusted: a) to eliminate the effect of sales and costs that occurred previous to the business combination between the Company and Molycorp Canada; b) to reflect the net incremental depreciation and amortization expense as a result of the allocation of the purchase price to certain depreciable and amortizable assets with useful lives ranging from two to 30 years; c) the tax effect of unaudited pro forma adjustments using the Molycorp federal, state and international statutory tax rates based on the applicable tax jurisdictions; and d) the estimated net increase of interest expense associated with the issuance of the Company's Senior Notes (as defined below) as part of the acquisition. The unaudited pro forma earnings of the combined entity for the nine months ended September 30, 2012, were also adjusted to exclude $115.2 million of non-recurring direct transaction costs. The weighted average number of shares outstanding utilized in the loss per share calculation have been adjusted to reflect the additional shares issued pursuant to the acquisition of Molycorp Canada and the Molibdenos y Metales S.A. equity financing.
	For the three and nine months ended September 30, 2012, the Company recognized approximately $0.5 million and $62.0 million of transaction costs, respectively, related to the acquisition of Molycorp Canada.

Accrued_Expenses

Accrued Expenses	9 Months Ended
	Sep. 30, 2013
Accrued Expenses [Abstract]	'
Accrued Expenses	'
	(12)Accrued Expenses
	Accrued expenses at September 30, 2013 and December 31, 2012 consisted of the following:
		September 30,		December 31,
		2013		2012
		(In thousands)
	Defined contribution plan	$	1,440	$	1,400
	Professional fees		133		4,971
	Accrued payroll and related benefits		7,254		7,532
	Sales and use tax		1,768		7,187
	Bonus accrual		3,846		3,503
	Interest payable		28,076		15,253
	Advance from customer		80		1,753
	Withholding taxes		3,433		2,929
	Amount payable to noncontrolling shareholder		6,211		9,640
	Other accrued expenses		9,204		4,845
	Total accrued expenses	$	61,445	$	59,013

Asset_Retirement_Obligation

Asset Retirement Obligation	9 Months Ended
	Sep. 30, 2013
Asset Retirement Obligation [Abstract]	'
Asset Retirement Obligation	'
	(13)Asset Retirement Obligation
	The following table presents the activity in the Company’s asset retirement obligation for the nine months ended September 30, 2013 and the year ended December 31, 2012:
		Nine months
		ended		Year Ended
		September 30,		December 31,
		2013		2012
		(In thousands)
	Balance at beginning of period	$	22,125	$	15,541
	Obligations settled		-2,384		-2,954
	Accretion expense		1,032		1,299
	Revisions in estimated cash flows		—		7,872
	Loss on settlement		—		367
	Balance at end of period	$	20,773	$	22,125
	The balances above as of September 30, 2013 and December 31, 2012 include a short-term portion of $6.7 million and $3.5 million, respectively, which were recorded under other current liabilities.
	During 2012, the Company increased its projected asset retirement obligation cash flows by approximately $7.9 million, of which $3.8 million related to the addition of new processing facilities at its Molycorp Mountain Pass facility and $4.1 million related to revised estimates for the demolition and reclamation of the old mill and mineral recovery areas at the same facility.
	The Company is required to provide the applicable governmental agencies with financial assurances relating to its closure and reclamation obligations. At September 30, 2013, the Company had financial assurance requirements of $28.8 million, which were satisfied with surety bonds placed with California state and regional agencies.

Debt_And_Capital_Lease_Obligat

Debt And Capital Lease Obligations	9 Months Ended
	Sep. 30, 2013
Debt And Capital Lease Obligations [Abstract]	'
Debt And Capital Lease Obligations	'
	(14)Debt and Capital Lease Obligations
	The following table provides a summary of the current and non-current portions of Molycorp's debt outstanding at September 30, 2013 and December 31, 2012:
		September 30, 2013				31-Dec-12
		Current		Non-Current		Current		Non-Current
		(In thousands)
	Bank loans due November 2013 - September 2017	$	14,812	$	3,072	$	39,252	$	4,118
	3.25% Convertible Notes, net of discount, due June 2016		—		204,903		—		198,689
	6.00% Convertible Notes, net of discount, due September 2017		—		342,883		—		331,977
	5.00% Debentures, net of discount, due December 2017		—		2,495		—		2,774
	5.50% Convertible Notes, net of discount, due February 2018		—		146,961		—		—
	10% Senior Secured Notes, net of discount, due June 2020		—		637,092		—		636,111
	Total debt		14,812		1,337,406		39,252		1,173,669
	Capital lease obligations		1,861		18,850		352		15,163
	Total debt and capital lease obligations	$	16,673	$	1,356,256	$	39,604	$	1,188,832
	Weighted average interest rate on the bank loans was 3.66% and 3.57% at September 30, 2013 and December 31, 2012, respectively.
	Scheduled minimum debt repayments, excluding capital lease obligations, are $13.8 million for the remainder of 2013, $1.5 million in 2014, $1.5 million in 2015, $230.8 million in 2016, $416.9 million in 2017 and $823.0 million thereafter.
	In May 2013, the Company entered into five capital lease agreements, each with a term of 48 months, for the use of certain mining equipment at its Molycorp Mountain Pass facility. The Company entered into an additional capital lease agreement for mining equipment in July 2013 with the same lender and for the same term of the other five leases. The aggregate amount of future minimum lease payments for all capital lease agreements entered between May and July 2013 was $6.6 million at inception of the leases, which included a nominal amount of executory costs and imputed interest of $0.6 million.
	At September 30, 2013, future minimum capital lease payments, comprised of the capital leases entered into in 2013 and a capital lease entered into during the second quarter of 2012, were $50.4 million, in the aggregate. Of this amount, $1.7 million is due in the remainder of 2013, $6.7 million is due in each of the three succeeding fiscal years, $5.7 million is due in the fifth year, and $22.9 million is due thereafter. The aggregate amount of future minimum lease payments at September 30, 2013 included total executory costs of $1.7 million and imputed interest of $27.9 million.
	During the first nine months of 2013, holders of $0.3 million aggregate principal amount of the Debentures elected to convert their notes at the same pro-ration of cash and shares consideration as if such holders had converted immediately prior to the acquisition of Molycorp Canada. As a result of this conversion, the Company paid a total of $0.2 million, including accrued interest, in cash with the remainder converted into 2,393 shares of Molycorp common stock.
	Additional detail on the convertible debt instruments that may be settled entirely or partially in cash upon conversion in a manner that reflects the issuer's economic interest cost is as follows:
		3.25% Convertible Notes				6.00% Convertible Notes				5.50% Convertible Notes
		At September 30,		At December 31,		At September 30,		At December 31,		At September 30,		At December 31,
		2013		2012		2013		2012		2013		2012
		(In thousands of dollars)
	Liability component (a)		201,905		196,702		339,304		330,177		146,166	n/a
	Equity component		36,251		36,251		68,695		68,695		21,815	n/a
		Three months ended September 30,
		2013		2012		2013		2012		2013		2012
	Accretion of liability component		1,772		1,651		2,888		1,147		918	n/a
	Interest cost (b)		3,988		3,854		9,969		7,740		3,609	n/a
	Capitalized interest		2,373		3,439		5,891		3,493		2,148	n/a
		Nine months ended September 30,
		2013		2012		2013		2012		2013		2012
	Accretion of liability component		5,203		4,849		8,491		1,147		2,382	n/a
	Interest cost (b)		11,839		11,446		29,691		7,740		9,482	n/a
	Capitalized interest		7,178		10,598		17,959		3,493		5,678	n/a
	(a) The liability component is the difference between the net proceeds and the equity component of a convertible note that can be settled in a combination of cash and shares of stock at the election of the issuer. The equity component represents the conversion feature of a convertible note and is treated as original issue discount in addition to the underwriting discount. The liability component includes the periodic amortization of the additional discount.
	(b) Interest cost includes the coupon interest, the accretion of the liability component, the accretion of the underwriting discount and the amortization of the issuance costs allocated to the liability component.
	Debt Issuance During First Quarter 2013
	On January 30, 2013, the Company issued $150.0 million aggregate principal amount of its 5.50% Convertible Senior Notes due 2018 (the “5.50% Convertible Notes”) in a registered public offering. Certain officers, directors and other related parties of the Company purchased $20.5 million of this aggregate principal amount. On March 1, 2013, the underwriters of such offering purchased an additional $22.5 million aggregate principal amount of the 5.50% Convertible Notes. After deducting the underwriting discounts and commissions, total net proceeds from the issuance of the 5.50% Convertible Notes were $165.6 million.
	The 5.50% Convertible Notes are Molycorp's senior unsecured obligations and pay a 5.50% interest semi-annually in arrears on February 1 and August 1 of each year, commencing on August 1, 2013. The 5.50% Convertible Notes are convertible at any time into shares of Molycorp's common stock, cash, or a combination thereof, at Molycorp's election. The conversion rate will initially be 138.8889 shares of Molycorp common stock per $1,000 principal amount of notes (equivalent to an initial conversion price of approximately $7.20 per share of Molycorp's common stock), subject to customary adjustments. The 5.50% Convertible Notes will mature on February 1, 2018, unless earlier repurchased, redeemed or converted in accordance with their terms prior to that date. Molycorp will have the right to redeem the 5.50% Convertible Notes on or after February 1, 2016 if the last reported sale price of its common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period. The 5.50% Convertible Notes rank equal in right of payment to existing and future liabilities that are not expressly subordinated to the 5.50% Convertible Notes, and rank effectively junior to Molycorp's existing and future secured indebtedness.
	The Company separately accounts for the liability and equity components of convertible debt instruments, such as the 5.50% Convertible Notes, that may be settled entirely or partially in cash upon conversion in a manner that reflects the issuer's economic interest cost. The additional discount on the liability component is amortized to interest cost over the term of the 5.50% Convertible Notes. The equity component of the 5.50% Convertible Notes is included in the additional paid-in capital section of the statement of stockholders' equity and is treated as original issue discount for purposes of accounting for the liability component. Details on the liability and equity component, accretion of liability component and interest cost of the 5.50% Convertible Notes are disclosed in the table above.
	Senior Secured Obligations
	The 10% Senior Secured Notes due 2020 ("Senior Notes") are senior secured obligations of Molycorp and are guaranteed by certain of Molycorp’s domestic subsidiaries ("Guarantors"). The Senior Notes are secured by a first-priority security interest on substantially all of the property and assets of the Company and the Guarantors, subject to some exceptions for certain "Excluded Assets," such as:
	·	Leasehold interests in real property;
	·	Certain capital leases that constitute permitted liens;
	·	Certain motor vehicles;
	·	Assets owned by foreign subsidiaries or, subject to certain limitations, MMA;
	·	Assets with a fair market value of less than $15.0 million as to which the board of directors determine in good faith (and certify to the collateral agent) that the costs of obtaining or perfecting such security interest are excessive in relation to the practical benefit to the holder of the Notes of the security afforded thereby (based on the value of such asset);
	·	Cash collateral for letters of credit or hedging obligations (up to 105% of the underlying obligations);
	·	Certain deposit accounts;
	·	The equity interests of immaterial subsidiaries and, subject to certain limitations, MMA;
	·	Voting stock of foreign subsidiaries in excess of 65.0% of the voting stock; and
	·	Other pledges of stock of a guarantor to the extent that Rule 3-16 of Regulation S-X under the Securities Act would require the filing of separate financial statements of such guarantor.

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2013
Income Taxes [Abstract]	'
Income Taxes	'
	(15)Income Taxes
	The Company's effective income tax rate was 19.11% for the first nine months of 2013. The Company's net loss before income taxes and equity earnings of $203.7 million for the nine months ended September 30, 2013 contained no material permanent differences between income for financial reporting purposes and tax purposes. Molycorp had net deferred income tax liabilities of $116.7 million at September 30, 2013 primarily related to the acquisition of Molycorp Canada.
	At September 30, 2013, Molycorp determined that a valuation allowance of $64.8 million was required. In making this determination, management analyzed, among other things, the Company's recent history of earnings and cash flows, forecasts of future earnings, and the nature and timing of future deductions and benefits represented by the deferred tax assets and liabilities. Additionally, management determined that changes in estimates regarding losses from the U.S. operations, coupled with finalizing its purchase price allocation and related deferred tax liabilities by jurisdiction relating to the Molycorp Canada acquisition, results in the potential for a valuation allowance on the U.S. net deferred tax assets at the end of 2013. As a result, the forecasted annualized effective tax rate for 2013 has been adjusted during the quarter ended September 30, 2013 to include this estimated valuation allowance.
	The Company has undistributed earnings of certain foreign subsidiaries at September 30, 2013, for which deferred taxes of $21.7 million been provided. Also, it had undistributed earnings of certain foreign subsidiaries at September 30, 2013, for which deferred taxes have not been provided. Such earnings are considered indefinitely invested in the foreign subsidiaries. If such earnings were repatriated, additional tax expense may result, although the calculation of such additional taxes is not practicable.
	The net tax effect of the elimination in consolidation of intercompany balances and transactions resulted in a deferred charge and income tax payable of $3.1 million at September 30, 2013.
	Each quarter the Company evaluates the liability for uncertain tax positions and, at September 30, 2013, had a $1.6 million liability for unrecognized tax benefits. Due to resolution with tax authorities, the Company's liability for uncertain tax positions was reduced by $4.7 million in the second quarter of 2013, which was recorded as a discrete item. As a result of the statute of limitations that expire in the next 12 months in various jurisdictions, and possible settlements of audit-related issues with taxing authorities in various jurisdictions, the Company believes that it is reasonably possible that the total amount of its net unrecognized income tax benefits will decrease by approximately $0.7 million in the next 12 months and, if recognized, would affect the Company's effective income tax rate.
	As a result of a change in the applicable withholding tax rate related to the unremitted earnings of a certain foreign subsidiary, deferred tax liabilities have decreased by $2.9 million. This decrease has been recorded as a discrete income tax benefit in the first quarter of 2013. In addition, as a result of the American Taxpayer Relief Act, which was signed into law on January 2, 2013, deferred tax liabilities related to the earnings of certain foreign subsidiaries have decreased by $5.8 million. These decreases have been recorded as a discrete income tax benefit in the first quarter of 2013.
	It is possible that the common stock offering completed in October 2013, in combination with past and future transactions involving the Company’s common stock, may cause an ownership change to occur that would limit the Company’s ability to use U.S. net operating loss carryforwards and other tax attributes.  However, if an ownership change were to occur, the Company does not anticipate a significant impact on its income tax benefit.

Stockholders_Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2013
Stockholders' Equity [Abstract]	'
Stockholders' Equity	'
	(16)Stockholders’ Equity
	At September 30, 2013 and December 31, 2012, the Company had 188,624,415 and 138,773,538 shares of common stock outstanding, respectively, and 2,070,000 shares of 5.50% Series A Mandatory Convertible Preferred Stock (“Convertible Preferred Stock”) outstanding. In each of the first, second and third quarters of 2013, the Company declared a cash dividend of $1.375 per share on the Convertible Preferred Stock and paid $2.8 million of the aggregate preferred dividend.
	On January 30, 2013, the Company issued 37,500,000 shares of its common stock at a price per share of $6.00 (the “2013 Primary Shares”). The underwriters of this public offering purchased an additional 5,625,000 shares of the 2013 Primary Shares at a price per share of $6.00 on February 5, 2013. The underwriters received a 6.00% fee in the form of an underwriter's discount for the 2013 Primary Shares. Certain officers, directors and other related parties of the Company participated in offering of the 2013 Primary Shares by purchasing 15,016,666 of the total 2013 Primary Shares issued. No underwriting fees were charged to the Company for the purchases of the 2013 Primary Shares by the insiders. After deducting the underwriting discounts and commissions, total net proceeds from the issuance of the 2013 Primary Shares were $248.6 million.
	Concurrently with the issuance of the 2013 Primary Shares, and in order to facilitate the offering of the 5.50% Convertible Notes, the Company entered into a share lending agreement with Morgan Stanley Capital Services LLC (“MSCS”), an affiliate of Morgan Stanley & Co. LLC, under which it agreed to loan to MSCS up to 7,666,666 shares of common stock (the “2013 Borrowed Shares”), of which 6,666,666 shares were offered through Morgan Stanley at a price per share of $6.00 in a registered public offering in the first quarter of 2013. MSCS did not exercise its option to borrow the remaining additional shares of common stock under this share lending agreement. The Company received no proceeds from the 2013 Borrowed Shares, but only a nominal lending fee from MSCS for the use of these loaned shares. The 2013 Borrowed Shares are issued and outstanding for corporate law purposes. However, based on certain contractual undertakings of MSCS in the share lending agreement that have the effect of substantially eliminating the economic dilution that otherwise would result from the issuance of the 2013 Borrowed Shares, these loaned shares will not be considered outstanding for the purpose of computing and reporting Molycorp's earnings per share.
	In connection with of the acquisition of Molycorp Canada on June 11, 2012, MCP Exchangeco Inc. issued an aggregate of 507,203 Exchangeable Shares in consideration for that portion of the purchase price Molycorp paid to Molycorp Canada’s former shareholders who elected to receive shares of MCP Exchangeco Inc. at the time of acquisition, and later convert the Exchangeable Shares into Molycorp common stock. During the first nine months of 2013, 12,971 Exchangeable Shares were converted into Molycorp common stock and, as of September 30, 2013, an aggregate of 353,167 Exchangeable Shares had been converted into shares of Molycorp common stock.

Loss_Per_Share

Loss Per Share	9 Months Ended
	Sep. 30, 2013
Loss Per Share [Abstract]	'
Loss Per Share	'
	(17)Loss per Share
	For the three and nine months ended September 30, 2013 and 2012, respectively, the dividends on the Convertible Preferred Stock were subtracted from net loss attributable to Molycorp stockholders for the purpose of computing the basic and diluted earnings per share.
		Three Months Ended September 30,				Nine Months Ended September 30,
	(In thousands, except share and per share amounts)	2013		2012		2013		2012
	Net loss attributable to Molycorp stockholders:	$	-69,929	$	-18,891	$	-180,072	$	-89,976
	Dividends on Convertible Preferred Stock		-2,846		-2,846		-8,539		-8,539
	Loss attributable to common stockholders		-72,775		-21,737		-188,611		-98,515
	Continuing operations		-68,589		-20,977		-183,421		-97,655
	Discontinued operations		-4,186		-760		-5,190		-860
		$	-72,775	$	-21,737	$	-188,611	$	-98,515
	Weighted average common shares outstanding—basic		168,114,266		117,086,022		163,222,000		101,147,638
	Basic loss per share:
	Continuing operations	$	-0.41	$	-0.18	$	-1.12	$	-0.97
	Discontinued operations		-0.02		-0.01		-0.03		-0.01
		$	-0.43	$	-0.19	$	-1.16	$	-0.97
	Diluted loss per share:
	Continuing operations	$	-0.41	$	-0.18	$	-1.12	$	-0.97
	Discontinued operations		-0.02		-0.01		-0.03		-0.01
		$	-0.43	$	-0.19	$	-1.16	$	-0.97
	Diluted earnings per share reflect the dilutive impact of potential common stock and unvested restricted shares of common stock in the weighted average number of common shares outstanding during the period, if dilutive. For this purpose, the “treasury stock method” and “if-converted method,” as applicable, are used.
	Under the treasury stock method, assumed proceeds upon the exercise of stock options are considered to be used to purchase common stock at the average market price of the shares during the period. Also under the treasury stock method, fixed awards and non-vested shares, such as restricted stock units, are deemed options for purposes of computing diluted earnings per share. At September 30, 2013 and 2012, all potential common stock under the treasury stock method were antidilutive in nature; consequently, the Company did not have any adjustments between earnings per share and diluted earnings per share related to stock options and restricted stock units.
	In applying the if-converted method, conversion is not assumed for purposes of computing diluted earnings per share if the effect would be antidilutive. Convertible preferred stock is antidilutive whenever the amount of the dividend declared in or accumulated for the current period per common share obtainable on conversion, including the deemed dividend in the period from a beneficial conversion feature, exceeds basic earnings per share. Molycorp's Convertible Preferred Stock was antidilutive at September 30, 2013 and 2012.
	Also, under the if-converted method, convertible debt is antidilutive whenever its interest per common share obtainable on conversion, including any deemed interest from a beneficial conversion feature and nondiscretionary adjustments, net of tax, exceeds basic earnings per share. At September 30, 2013 and 2012, all of the Company's convertible notes were antidilutive.

StockBased_Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2013
Stock-Based Compensation [Abstract]	'
Stock-Based Compensation	'
	(18)Stock-Based Compensation
	Molycorp has stock-based compensation plans for executives, eligible employees and non-employee directors. Stock-based awards issued under these plans include stock options to purchase shares of the Company’s common stock, restricted stock awards (“RSAs”), restricted stock units (“RSUs”) and performance-based restricted stock units ("PBRSUs"). The Company recognized total stock-based compensation expenses of $1.6 million and $1.0 million for the three months ended September 30, 2013 and 2012, respectively, and $2.4 million and $2.9 million for the nine months ended September 30, 2013 and 2012, respectively. Included in the stock-based compensation expenses for the three and nine months ended September 30, 2013 were forfeiture benefits of $0.2 million and $1.4 million, respectively.
	In December 2012, the Company introduced an Employee Stock Purchase Plan ("ESPP") to provide eligible employees with an opportunity to acquire a proprietary interest in the Company through the purchase of its common stock at a discount over the stock fair market value. The ESPP is implemented by sequential offering periods, the commencement and duration of which are determined by the Board of Directors of Molycorp. For the first and second offering period the Company recognized a stock-based compensation expense of $0.1 million related to the ESPP.
	During the first nine months of 2013 and 2012, the Company granted RSUs to certain non-employee directors who elected to convert a portion of their quarterly cash retainer into restricted stock. These converted RSUs are fully vested because they relate to services already rendered by the non-employee directors. The same non-employee directors who elected to convert their cash retainer into RSUs, received additional RSUs as matching contributions by the Company equal to 25% of the converted units. The matching RSUs vest on the third anniversary of the grant date.
	The following tables summarize the 2013 year-to-date activity for to all stock-based awards:
			Weighted
			Average
		Number of	Grant-Date
	PBRSUs	Shares	Price
	Unvested at January 1, 2013	29,302	$	30.33
	Granted	897,515	$	6.76
	Forfeited	-65,143	$	11.17
	Vested	—		—
	Unvested at September 30, 2013	861,674	$	7.23
			Weighted
			Average
		Number of	Grant-Date
	RSUs	Shares	Price
	Unvested at January 1, 2013	181,602	$	32.15
	Granted	997,979	$	7.04
	Forfeited	-80,510	$	28.06
	Vested*	-19,632	$	7.56
	Unvested at September 30, 2013	1,079,439	$	9.82
	*  Includes deferral and conversion of a portion of fees payable to certain non-employee directors of the Company.
			Weighted
			Average
		Number of	Grant-Date
	RSAs	Shares	Price
	Unvested at January 1, 2013	39,974	$	40.09
	Granted	—		—
	Forfeited	-8,143	$	39.76
	Vested	—		—
	Unvested at September 30, 2013	31,831	$	37.87
			Weighted
			Average
		Number of	Grant-Date
	Stock Options	Shares	Price
	Outstanding at January 1, 2013	35,624	$	48.87
	Granted	—		—
	Exercised	—		—
	Forfeited and expired	-9,008	$	48.87
	Outstanding at September 30, 2013	26,616	$	48.87
	Options exercisable at September 30, 2013	17,744	$	48.87

Commitments_And_Contingencies

Commitments And Contingencies	9 Months Ended
	Sep. 30, 2013
Commitments And Contingencies [Abstract]	'
Commitments And Contingencies	'
	(19)Commitments and Contingencies
	(a)	Future Operating Lease Commitments
	The Company has certain operating leases for office space, trailers and certain equipment. Remaining annual minimum payments under these leases at September 30, 2013 were as follows:
				Less Than 1						More Than 5
		Total		Year		1 - 3 Years		4 - 5 Years		Years
		(In thousands)
	Operating lease obligations	$	6,966	$	2,667	$	2,824	$	437	$	1,038
	(b)	Purchase Commitments
	The Company entered into contractual commitments for the purchase of materials and services from various vendors, primarily in connection with the Molycorp Mountain Pass facility modernization and expansion efforts. Future payments for all purchase commitments at September 30, 2013 were as follows:
				Less Than 1						More Than 5
		Total		Year		1 - 3 Years		4 - 5 Years		Years
		(In thousands)
	Purchase obligations and other commitment	$	251,361	$	227,365	$	13,206	$	6,487	$	4,303
	(c)	Labor Contract
	Certain Molycorp Mountain Pass facility employees are covered by a collective bargaining agreement with the United Steelworkers of America that expires on March 15, 2015. At September 30, 2013,  237 employees, or approximately 61% of the Company’s workforce at the Molycorp Mountain Pass facility, were covered by this collective bargaining agreement.
	At September 30, 2013,  174 employees, or approximately 30% of the workforce at the Company’s Molycorp Silmet facility, were unionized employees. The contract with the labor union in Estonia was renewed in February 2012.
	(d)	Reclamation Surety Bonds
	At September 30, 2013, Molycorp had placed $28.8 million of surety bonds with California state and regional agencies to secure its Mountain Pass facility closure and reclamation obligations.
	(e)	Purported Class Action and Derivative Lawsuits
	In February 2012, a purported class action lawsuit was filed in the U.S. District Court for the District of Colorado against the Company and certain of its current and former executive officers alleging violations of the federal securities laws. The Consolidated Class Action Complaint filed on July 31, 2012 also names most of the Company’s Board members and some of the Company’s stockholders as defendants, along with other persons and entities. That Complaint alleges 18 claims for relief arising out of alleged: (1) securities fraud in violation of the Securities Exchange Act of 1934, or the Exchange Act, during the proposed class period from February 11, 2011 through November 10, 2011; and (2) materially untrue or misleading statements in registration statements and prospectuses for the Company’s public offering of preferred stock in February 2011 and of common stock in June 2011, in violation of the Securities Act. The Company’s motion to dismiss that Complaint was filed in October 2012 and is pending. The Company believes that this lawsuit is without merit, and it intends to vigorously defend itself against these claims.
	In addition, as of November 21, 2012, a consolidated stockholder derivative lawsuit filed purportedly on the Company’s behalf against the Company (as a nominal defendant) and certain of its directors, current and former executive officers and stockholders is pending in the Delaware Court of Chancery. In August 2012, a consolidated amended shareholder derivative complaint was filed, asserting causes of action for alleged: (1) breach of fiduciary duty, including the duties of loyalty and due care; (2) breach of fiduciary duty not to trade on or misuse material non-public information; (3) unjust enrichment; and (4) aiding and abetting a breach of fiduciary duty. On the Company’s behalf, the plaintiffs in the consolidated derivative action seek, among other things, monetary damages, restitution, and an accounting. The defendants filed motions to dismiss and motions to stay that action in October 2012. Pursuant to an order dated May 15, 2013, the Delaware Court of Chancery stayed the derivative lawsuit pending final disposition of the purported class action lawsuit. In October 2013, certain plaintiffs, on our behalf, filed a motion to lift the May 15, 2013 stay order. The defendants’ brief in opposition and the motion to lift the stay order are due to be filed on or before November 25, 2013.  Two additional stockholder derivative lawsuits that were filed in the U.S. District Court in Colorado have been dismissed, but the plaintiffs in those cases pursued an appeal of that ruling in the U.S. Court of Appeals for the Tenth Circuit. On August 20, 2013, the Tenth Circuit remanded these cases back to the Colorado District Court. The Company and the plaintiffs have filed their respective briefs in the remanded proceeding and the decision of the Colorado District Court is pending.
	In August 2013, two purported class action lawsuits were filed in the U.S. District Court for the Southern District of New York against the Company and certain of its current and former executive officers, alleging violations of the federal securities laws.  The purported class action lawsuits allege claims for relief arising out of alleged securities fraud in violation of the Exchange Act during the proposed class period from August 2, 2012 through August 7, 2013.  Pursuant to stipulations and orders of the court dated September 25, 2013 and September 27, 2013, among other things, the deadlines for the Company and its current and former executive officers to respond to the lawsuits have been stayed pending appointment of a lead plaintiff under the Private Securities Litigation Reform Act. The Company believes that the lawsuits are without merit and it intends to vigorously defend itself against the claims.
	Due to the inherent uncertainties of litigation and regulatory proceedings, including the current purported class action lawsuit and derivative lawsuits, the Company cannot determine with certainty the ultimate outcome of any such litigation or proceedings. If the final resolution of any such litigation or proceedings is unfavorable, the Company’s financial condition, operating results and cash flows could be materially affected.

Concentrations

Concentrations	9 Months Ended
	Sep. 30, 2013
Concentrations [Abstract]	'
Concentrations	'
	(20)Concentrations
	(a)	Products
	There were no significant sales by product at the Resources segment for the three and nine months ended September 30, 2013. Sales of neodymium/praseodymium products were 10% of consolidated revenues for the nine months ended September 30, 2012 at the Resources segment.
	The Chemicals and Oxides segment includes sales of REO, zirconium-based engineered materials and mixed rare earth/zirconium oxides from the acquisition of Molycorp Canada on June 11, 2012. Sales of cerium products within the Chemicals and Oxides segment accounted for approximately  8% and 10% of consolidated revenues for the three and nine months ended September 30, 2013, respectively, and approximately 16% and 11% of consolidated revenues for the three and nine months ended September 30, 2012, respectively. The Chemicals and Oxides segment also sold neodymium/praseodymium products for approximately 12% of consolidated revenues during the three months ended September 30, 2012.
	Within the Magnetic Materials and Alloys segment, sales of Neo Powders™ were approximately 45% and 40% of consolidated revenues for the three and nine months ended September 30, 2013, respectively, 34% for the three months ended September 30, 2012 and 22% for the period from June 12, 2012 to September 30, 2012. The Neo Powders™ were introduced into Molycorp's product mix with the acquisition of Molycorp Canada on June 11, 2012.
	There were no significant sales by product at the Rare Metals segment for the three and nine months ended September 30, 2013 and 2012.
	(b)	Customers
	For the three and nine months ended September 30, 2013, the Magnetic Materials and Alloys segment sold Neo Powders™ for $16.3 million and $39.2 million, respectively, to Daido Electronics.
	There were no significant sales to individual customers relative to consolidated revenues at any of the Company's segments during the three and nine months ended September 30, 2012.

RelatedParty_Transactions

Related-Party Transactions	9 Months Ended
	Sep. 30, 2013
Related-Party Transactions [Abstract]	'
Related-Party Transactions	'
	(21)Related-Party Transactions
	The Company supplies Neo Powders™ to TMT to produce rare earth magnetic compounds. Molycorp then purchases these compounds back from TMT in its normal course of business. Additionally, Keli processes rare earth oxides into metals for inclusion in the Neo Powders™.
	For the three and nine months ended September 30, 2013, the Company sold $0.7 million and $2.7 million, respectively, of Neo Powders™ to TMT, and purchased rare earth magnetic compounds from TMT for $0.6 million and $1.5 million, respectively. During the third quarter of 2012 and for the period from June 12, 2012 to September 30, 2012, the Company sold $1.3 million and $1.4 million of Neo Powders™ to TMT, respectively, and purchased $1.4 million and $1.9 million worth of compounds from TMT during the same respective periods.
	The Company purchased metals and received services from Keli for a total of $20.4 million and $44.8 million, during the three and nine months ended September 30, 2013, respectively, and $16.1 million and $21.4 million for the third quarter of 2012 and the period from June 12, 2012 to September 30, 2012, respectively.
	Ingal Stade sells gallium to the Company's facilities located in Ontario, Canada and to some of its facilities in the United States. The Company purchased $1.1 million and $3.4 million of gallium metal from Ingal Stade for the three and nine months ended September 30, 2013, respectively, and $1.3 million and $1.7 million during the third quarter of 2012 and the period from June 12, 2012 to September 30, 2012, respectively.
	During the three and nine months ended September 30, 2013, the Company sold $16.3 million and $39.2 million, respectively, of Neo Powders™ to Daido Electronics, a subsidiary of one of IMJ’s shareholders.

Net_Change_In_Operating_Assets

Net Change In Operating Assets And Liabilities	9 Months Ended
	Sep. 30, 2013
Net Change In Operating Assets And Liabilities [Abstract]	'
Net Change In Operating Assets And Liabilities	'
	(22)Net Change in Operating Assets and Liabilities
	Net change in operating assets and liabilities, net of the effects of acquisitions and dispositions, consisted of the following for nine months ended September 30, 2013 and 2012:
		Nine Months Ended September 30,
		2013		2012
		(In thousands)
	Decrease (increase) in operating assets:
	Accounts receivable	$	-5,557	$	88,997
	Inventory		26,816		13,202
	Prepaid expenses and other assets		-1,085		7,174
	Increase (decrease) in operating liabilities:
	Accounts payable		-16,642		-43,223
	Income tax payable		-8,768		-39,483
	Interest payable		-26,765		-9,704
	Asset retirement obligation		-2,385		—
	Accrued expenses		-10,826		-49,044
		$	-45,212	$	-32,081

Derivative_Instruments

Derivative Instruments	9 Months Ended
	Sep. 30, 2013
Derivative Instruments [Abstract]	'
Derivative Instruments	'
	(23)Derivative Instruments
	Put Option
	As a result of the acquisition of Molycorp Canada, the Company assumed a liability associated with the put option issued to holders of the noncontrolling interest of Buss & Buss, a business acquired by Molycorp Canada's predecessor company. The Buss & Buss put option relates to a share purchase agreement (“SPA”) between NMT Holding GmbH, a German subsidiary of the Company, and the shareholders of Buss & Buss entered into May 27, 2010 by Molycorp Canada's predecessor company. The SPA includes a call and a put option on shares of the remaining shareholder and his legal successors. If the call option is exercised by the Company, a premium is added to the consideration to purchase the underlying shares in Buss & Buss. If the put option is exercised by the remaining shareholder of Buss & Buss or his legal successors, a discount will reduce the cost basis of the securities sold to the Company. The Company does not account for this derivative as a hedge. The put option had a fair value of $6.8 million at September 30, 2013, recorded as "Derivative liability" in the condensed consolidated balance sheet. The change in fair value of the put option resulted in an unrealized loss of $0.2 million and an unrealized gain of $1.0 million for the three and nine months ended September 30, 2013, respectively, and an unrealized gain of $0.2 million for the period from June 12, 2012 to September 30, 2012, which were recognized in "Interest expense" in the condensed consolidated statements of operations and comprehensive income. The technique Molycorp used to fair value this derivative is the income approach based on a discounted cash flow model. With the exception of the risk free interest rate, which is a Level 1 input within the fair value hierarchy, all other inputs used to fair value this put option are based on unobservable Level 3 inputs based on management's assumptions. These inputs include: equity-risk premium, risk premium, size premium and growth rate. Any reasonably foreseeable changes in assumed levels of unobservable inputs used to fair value this put option would not be expected to have a material impact on the Company's financial position or results of operations.
	2012 Contingent Forward Contract
	On March 28, 2012, the Company entered into a contingent forward contract to purchase Canadian dollars with a notional amount of Cdn$870.0 million to manage the foreign currency exposure with respect to its planned acquisition of Molycorp Canada. The Company did not apply hedge accounting to this contingent forward contract. Upon settlement of this derivative on June 11, 2012 (the date of the Molycorp Canada acquisition), the Company recognized a loss of $37.6 million in "Other expense" in the condensed consolidated statement of operations and comprehensive income. Of this loss, $6.7 million was recognized during the three months ended March 31, 2012 and the remainder during the second quarter of 2012.

Employee_Benefit_Plans_And_Sev

Employee Benefit Plans And Severance Charges	9 Months Ended
	Sep. 30, 2013
Employee Benefit Plans And Severance Charges [Abstract]	'
Employee Benefit Plans And Severance Charges	'
	(24)Employee Benefit Plans and Severance Charges
	Employee Benefit Plans
	Defined Contribution Retirement Plans
	The Company maintains defined contribution retirement plans for all U.S. employees. The Company currently makes Safe Harbor Matching Contributions in an amount equal to 100% of the first 3% contributed and 50% of the next 2% contributed by each eligible employee. In addition, the Company may determine to make discretionary matching or nonelective employer (profit sharing) contributions in an amount designated by the Company. Discretionary matching contributions, if any, will be based on a percentage of employee contributions to the defined contribution plans each year, as designated by the Company. The Company's Safe Harbor Matching Contributions will always be 100% vested. Employees become 100% vested in Company discretionary matching contributions and/or nonelective employer contributions, if any, after 3 years of service.
	Expenses related to this plan totaled $0.7 million and $0.4 million for the three months ended September 30, 2013 and 2012, respectively, and $2.2 million and $1.0 million for the nine months ended September 30, 2013 and 2012, respectively.
	Defined Benefit Pension Plan and Other Post-Retirement Benefits
	In accordance with the terms of the Arrangement Agreement, the Company maintained the terms of the benefit plans for Molycorp Canada’s current and former employees. Molycorp Canada's predecessor company had a defined benefit pension plan (“Pension Plan”), which covered all hourly employees employed as of September 30, 1995, and all hourly employees subsequently hired by Molycorp Canada's predecessor company up to 2003 at its former U.S. manufacturing facility in Anderson, Indiana. A December 31 measurement date is used for the Pension Plan.
	The Company also maintained the terms of Molycorp Canada post-retirement medical and life insurance benefits plan for certain employees from the Anderson, Indiana manufacturing facility. The measurement date for this post-retirement benefit plan (“PBP”) is December 31. The actuarial valuation for funding purposes of the Pension Plan and PBP is January 1 of each year.
	The Company's total contribution to the Pension Plan and PBP is expected to be approximately $0.2 million in 2013.
	The components of the Pension Plan and PBP net periodic benefit cost for the three and nine months ended September 30, 2013, and for the period from June 12, 2012 to September 30, 2012, are set forth below:
	Three Months Ended September 30, 2013	Pension Plan		PBP		Total
		(In thousands)
	Components of net periodic benefit cost:
	Service Cost	$	—	$	—	$	—
	Interest cost		78		2		80
	Expected return on plan assets		-68		—		-68
	Amortization of transition obligation/(asset)		—		—		—
	Amortization of prior service cost		—		-1		-1
	Amortization of actuarial loss		63		-2		61
	Net periodic benefit cost	$	73	$	-1	$	72
	Nine Months Ended September 30, 2013	Pension Plan		PBP		Total
		(In thousands)
	Components of net periodic benefit cost:
	Service Cost	$	—	$	—	$	—
	Interest cost		234		6		240
	Expected return on plan assets		-203		—		-203
	Amortization of transition obligation/(asset)		—		—		—
	Amortization of prior service cost		—		-3		-3
	Amortization of actuarial loss		189		-6		183
	Net periodic benefit cost	$	220	$	-3	$	217
	Period from June 12, 2012 to September 30, 2012	Pension Plan		PBP		Total
		(In thousands)
	Components of net periodic benefit cost:
	Service Cost	$	—	$	—	$	—
	Interest cost		90		—		90
	Expected return on plan assets		-67		—		-67
	Amortization of transition obligation/(asset)		—		—		—
	Amortization of prior service cost		-1		—		-1
	Amortization of actuarial loss		55		—		55
	Net periodic benefit cost	$	77	$	—	$	77
	Severance Charges
	In the first quarter of 2013, the Company took a number of actions throughout the organization as part of its continuing effort to contain costs and increase the efficiency of its operations. As a result, the Company reduced a portion of its workforce, primarily within the Corporate group, and recognized employee severance and benefit costs of $2.1 million through the third quarter of 2013, which were included in "Selling, general and administrative” expense in the condensed consolidated statement of operations and comprehensive income. As of September 30, 2013, the Company paid $1.6 million of these severance benefits using the Company's cash balance available at that time. The remainder will be paid over five months from September 30, 2013.
	In relation to the Company’s plan to discontinue operations at the Napanee facility in July 2013, the Company recognized employee severance and benefit costs of $0.1 million at the beginning of the third quarter of 2013, which were substantially paid as of September 30, 2013. These severance and benefit costs were included in the results of discontinued operations in the condensed consolidated statements of operations and comprehensive income.

Subsidiary_Guarantor_Financial

Subsidiary Guarantor Financial Information	9 Months Ended
	Sep. 30, 2013
Subsidiary Guarantor Financial Information [Abstract]	'
Subsidiary Guarantor Financial Information	'
	(25)Subsidiary Guarantor Financial Information
	The Senior Notes are jointly, severally and unconditionally guaranteed by all of Molycorp, Inc.'s existing and future domestic material subsidiaries, as defined in the indenture governing the Senior Notes. The Senior Notes guarantee of a guarantor will automatically terminate, and the obligations of such guarantor under the Senior Notes guarantee will be unconditionally released and discharged, upon (all terms as defined in the indenture governing the Senior Notes):
	-1	any sale, exchange, transfer or other disposition of a majority of the capital stock of (including by way of consolidation or merger) such guarantor by Molycorp or any restricted subsidiary to any person or persons, as a result of which such guarantor is no longer a direct or indirect subsidiary of Molycorp;
	-2	any sale, exchange, transfer or other disposition of all or substantially all assets of such guarantor that results in such guarantor having no assets;
	-3	the designation by Molycorp of such guarantor as an unrestricted subsidiary; or
	-4	defeasance or discharge of the Senior Notes;
	provided that any such event occurs in accordance with all other applicable provisions of the indenture.
	Presented below are the condensed consolidating financial statements of Molycorp, Inc. (“Parent”) as issuer, its combined guarantor subsidiaries and its combined non-guarantor subsidiaries, which are presented as an alternative to providing separate financial statements for the guarantors. The accounts of the Parent, the guarantor and non-guarantor subsidiaries are presented using the equity method of accounting for investments in subsidiaries for purposes of these condensed consolidating financial statements only. Certain of the prior periods separate financial information has been reclassified to conform to the presentation of the most recent period herein disclosed.
		At September 30, 2013
		(In thousands)
				Guarantor			Non-Guarantor				Molycorp, Inc.
	Condensed Consolidating Balance Sheets	Parent		Subsidiaries			Subsidiaries		Eliminations		consolidated
	Current assets:
	Cash and cash equivalents	$	31,207	$	8,914		$	133,793	$	—	$	173,914
	Trade accounts receivable, net		—		3,012			55,188		—		58,200
	Inventory		—		34,044			149,397		—		183,441
	Deferred charges		—		1,329			1,751		—		3,080
	Deferred tax assets		—		—			8,478		—		8,478
	Income tax receivable		—		20,243			53		—		20,296
	Prepaid expenses and other current assets		—		9,559			16,101		—		25,660
	Total current assets		31,207		77,101			364,761		—		473,069
	Non-current assets:
	Deposits		1,754		24,243			—		—		25,997
	Property, plant and equipment, net		—		1,620,346			158,738		—		1,779,084
	Inventory		—		24,325			—		—		24,325
	Intangible assets, net		—		459			419,012		—		419,471
	Investments		—		43,425			15,324		—		58,749
	Goodwill		—		—			239,742		—		239,742
	Investments in consolidated subsidiaries		699,379		122,784			—		-822,163		—
	Intercompany accounts receivable		1,920,116		—			791		-1,920,907		—
	Other non-current assets		—		785			6,054		—		6,839
	Total non-current assets		2,621,249		1,836,367			839,661		-2,743,070		2,554,207
	Total assets	$	2,652,456	$	1,913,468		$	1,204,422	$	-2,743,070	$	3,027,276
	Current liabilities:
	Trade accounts payable	$	—	$	70,498		$	37,384	$	—	$	107,882
	Accrued expenses		27,695		12,375			21,375		—		61,445
	Income tax payable		—		7			8,432		-6,731		1,708
	Debt and capital lease obligations		—		1,861			14,812		—		16,673
	Other current liabilities		—		6,689			—		—		6,689
	Total current liabilities		27,695		91,430			82,003		-6,731		194,397
	Non-current liabilities:
	Asset retirement obligation		—		14,084			—		—		14,084
	Deferred tax liabilities		—		—			118,411		6,731		125,142
	Debt and capital lease obligations		1,331,839		18,850			5,567		—		1,356,256
	Derivative liability		—		—			6,819		—		6,819
	Pension liabilities		—		—			3,431		—		3,431
	Intercompany accounts payable		—		1,916,264			4,643		-1,920,907		—
	Other non-current liabilities		—		1,340			712		—		2,052
	Total non-current liabilities		1,331,839		1,950,538			139,583		-1,914,176		1,507,784
	Total liabilities	$	1,359,534	$	2,041,968		$	221,586	$	-1,920,907	$	1,702,181
	Stockholders’ equity:
	Common stock		189		—			—		—		189
	Preferred stock		2		—			—		—		2
	Additional paid-in capital		1,946,742		149,857			1,316,079		-1,465,936		1,946,742
	Accumulated other comprehensive loss		-7,848		—			-7,848		7,848		-7,848
	Accumulated deficit		-646,163		-278,357			-357,568		635,925		-646,163
	Total Molycorp stockholders’ equity		1,292,922		-128,500			950,663		-822,163		1,292,922
	Noncontrolling interests		—		—			32,173		—		32,173
	Total stockholders’ equity		1,292,922		-128,500			982,836		-822,163		1,325,095
	Total liabilities and stockholders’ equity	$	2,652,456	$	1,913,468		$	1,204,422	$	-2,743,070	$	3,027,276
		At December 31, 2012
		(In thousands)
				Guarantor			Non-Guarantor				Molycorp, Inc.
Condensed Consolidating Balance Sheets	Parent		Subsidiaries			Subsidiaries		Eliminations		consolidated
Current assets:
Cash and cash equivalents	$	16,560	$	18,020		$	193,210	$	—	$	227,790
Trade accounts receivable, net		—		7,738			44,692		—		52,430
Inventory		—		49,416			237,960		—		287,376
Deferred charges		—		2,203			7,209		—		9,412
Deferred tax assets		—		—			11,731		-1,942		9,789
Income tax receivable		—		25,087			—		—		25,087
Prepaid expenses and other current assets		—		9,085			12,709		—		21,794
Total current assets		16,560		111,549			507,511		-1,942		633,678
Non-current assets:
Deposits		1,752		24,862			155		—		26,769
Property, plant and equipment, net		—		1,377,147			167,157		—		1,544,304
Inventory		—		26,096			—		—		26,096
Intangible assets, net		—		508			450,430		—		450,938
Investments		—		45,241			18,795				64,036
Deferred tax assets		6,030		—			—		-6,030		—
Goodwill		—		—			239,742		—		239,742
Investments in consolidated subsidiaries		883,319		97,960			—		-981,279		—
Intercompany accounts receivable		1,539,877		207,035			794		-1,747,706		—
Other non-current assets		—		885			6,087		—		6,972
Total non-current assets		2,430,978		1,779,734			883,160		-2,735,015		2,358,857
Total assets	$	2,447,538	$	1,891,283		$	1,390,671	$	-2,736,957	$	2,992,535
Current liabilities:
Trade accounts payable	$	—	$	191,769		$	50,225	$	—	$	241,994
Accrued expenses		14,872		10,087			34,054		—		59,013
Income tax payable		—		—			15,267		—		15,267
Deferred tax liabilities		—		1,942			—		-1,942		—
Debt and capital lease obligations		—		352			39,252		—		39,604
Other current liabilities		—		3,539			—		—		3,539
Total current liabilities		14,872		207,689			138,798		-1,942		359,417
Non-current liabilities:
Asset retirement obligation		—		18,586			—		—		18,586
Deferred tax liabilities		—		23,130			143,575		-6,030		160,675
Debt and capital lease obligations		1,166,777		15,163			6,892		—		1,188,832
Derivative liability		—		—			7,816		—		7,816
Pension liabilities		—		—			3,292		—		3,292
Intercompany accounts payable		49,843		1,577,363			120,500		-1,747,706		—
Other non-current liabilities		—		1,102			1,557		—		2,659
Total non-current liabilities		1,216,620		1,635,344			283,632		-1,753,736		1,381,860
Total liabilities	$	1,231,492	$	1,843,033		$	422,430	$	-1,755,678	$	1,741,277
Stockholders’ equity:
Common stock		139		—			—		—		139
Preferred stock		2		—			—		—		2
Additional paid-in capital		1,691,429		149,857			1,283,863		-1,433,720		1,691,429
Accumulated other comprehensive loss		-9,433		—			-9,433		9,433		-9,433
Accumulated deficit		-466,091		-101,607			-341,401		443,008		-466,091
Total Molycorp stockholders’ equity		1,216,046		48,250			933,029		-981,279		1,216,046
Noncontrolling interests		—		—			35,212		—		35,212
Total stockholders’ equity		1,216,046		48,250			968,241		-981,279		1,251,258
Total liabilities and stockholders’ equity	$	2,447,538	$	1,891,283		$	1,390,671	$	-2,736,957	$	2,992,535
	Three months ended September 30, 2013
	(In thousands)
Condensed Consolidating Statements of Operations and			Guarantor			Non-Guarantor				Molycorp, Inc.
Comprehensive Loss	Parent		Subsidiaries			Subsidiaries		Eliminations		consolidated
Revenues	$	—	$	19,237		$	142,421	$	-12,592	$	149,066
Costs of sales:
Costs excluding depreciation and amortization		—		-55,517			-107,519		12,592		-150,444
Depreciation and amortization		—		-9,336			-7,064		—		-16,400
Gross (loss) profit		—		-45,616			27,838		—		-17,778
Operating expenses:
Selling, general and administrative		-3		-15,554			-8,842		—		-24,399
Corporate development		—		-69			—		—		-69
Depreciation, amortization and accretion		—		-1,597			-8,475		—		-10,072
Research and development		—		-1,037			-4,528		—		-5,565
Impairment of goodwill and other long-lived assets		—		—			-1,118		—		-1,118
Operating (loss) income		-3		-63,873			4,875		—		-59,001
Other (expense) income:
Other income (expense)		4		64			-725		—		-657
Foreign exchange gains (losses), net		1,727		-1			-1,960		—		-234
Interest expense, net		-14,093		-744			-1,452		—		-16,289
Interest income (expense) from intercompany notes		9,211		1,412			-10,623		—		—
Equity loss from consolidated subsidiaries		-54,858		-333			—		55,191		—
		-58,009		398			-14,760		55,191		-17,180
Loss before income taxes and equity earnings		-58,012		-63,475			-9,885		55,191		-76,181
Income tax benefit (expense)		-11,914		14,879			9,937		—		12,902
Equity in results of affiliates		—		-1,617			-717		—		-2,334
Loss from continuing operations		-69,926		-50,213			-665		55,191		-65,613
Loss from discontinued operations, net of tax		—		—			-4,186		—		-4,186
Net loss		-69,926		-50,213			-4,851		55,191		-69,799
Net income attributable to noncontrolling interest		—		—			-130		—		-130
Net loss attributable to Molycorp stockholders	$	-69,926	$	-50,213		$	-4,981	$	55,191	$	-69,929
Net loss	$	-69,926	$	-50,213		$	-4,851	$	55,191	$	-69,799
Other comprehensive loss:
Foreign currency translation adjustments		—		—			4,217		—		4,217
Comprehensive loss	$	-69,926	$	-50,213		$	-634	$	55,191	$	-65,582
Comprehensive loss attributable to:
Molycorp stockholders		-69,926		-50,213			-504		55,191		-65,452
Noncontrolling interest		—		—			-130		—		-130
	$	-69,926	$	-50,213		$	-634	$	55,191	$	-65,582
	Nine months ended September 30, 2013
	(In thousands)
Condensed Consolidating Statements of Operations and			Guarantor			Non-Guarantor				Molycorp, Inc.
Comprehensive Loss	Parent		Subsidiaries			Subsidiaries		Eliminations		consolidated
Revenues	$	—	$	68,014		$	397,548	$	-34,982	$	430,580
Costs of sales:
Costs excluding depreciation and amortization		—		-147,209			-309,472		34,982		-421,699
Depreciation and amortization		—		-28,523			-20,760		—		-49,283
Gross (loss) profit		—		-107,718			67,316		—		-40,402
Operating expenses:
Selling, general and administrative		-3		-48,870			-27,573		—		-76,446
Corporate development		—		-256			—		—		-256
Depreciation, amortization and accretion		—		-3,258			-23,015		—		-26,273
Research and development		—		-4,428			-14,048		—		-18,476
Impairment of goodwill and other long-lived assets		—		—			-1,495		—		-1,495
Operating (loss) income		-3		-164,530			1,185		—		-163,348
Other (expense) income:
Other income		4		298			1,128		—		1,430
Foreign exchange gains (losses), net		1,727		8			-691		—		1,044
Interest (expense) income, net		-39,978		-5,039			2,210		—		-42,807
Interest income (expense) from intercompany notes		27,455		4,293			-31,748		—		—
Equity loss from consolidated subsidiaries		-163,247		-6,742			—		169,989		—
		-174,039		-7,182			-29,101		169,989		-40,333
Loss before income taxes and equity earnings		-174,042		-171,712			-27,916		169,989		-203,681
Income tax benefit (expense)		-6,030		23,130			21,822		—		38,922
Equity in results of affiliates		—		-5,239			-3,451		—		-8,690
Loss from continuing operations		-180,072		-153,821			-9,545		169,989		-173,449
Loss from discontinued operations, net of tax		—		—			-5,190		—		-5,190
Net loss		-180,072		-153,821			-14,735		169,989		-178,639
Net income attributable to noncontrolling interest		—		—			-1,433		—		-1,433
Net loss attributable to Molycorp stockholders	$	-180,072	$	-153,821		$	-16,168	$	169,989	$	-180,072
Net loss	$	-180,072	$	-153,821		$	-14,735	$	169,989	$	-178,639
Other comprehensive loss:
Foreign currency translation adjustments		—		—			1,585		—		1,585
Comprehensive loss	$	-180,072	$	-153,821		$	-13,150	$	169,989	$	-177,054
Comprehensive loss attributable to:
Molycorp stockholders		-180,072		-153,821			-11,717		169,989		-175,621
Noncontrolling interest		—		—			-1,433		—		-1,433
	$	-180,072	$	-153,821		$	-13,150	$	169,989	$	-177,054
	Three months ended September 30, 2012
	(In thousands)
Condensed Consolidating Statements of Operations and			Guarantor			Non-Guarantor				Molycorp, Inc.
Comprehensive Loss	Parent		Subsidiaries			Subsidiaries		Eliminations		consolidated
Revenues	$	—	$	26,103		$	191,661	$	-12,559	$	205,205
Costs of sales:
Costs excluding depreciation and amortization		—		-38,919			-156,867		12,559		-183,227
Depreciation and amortization		—		-3,375			-7,237		—		-10,612
Gross (loss) profit		—		-16,191			27,557		—		11,366
Operating expenses:
Selling, general and administrative		-29		-20,147			-11,173		—		-31,349
Corporate development		—		-1,073			—		—		-1,073
Depreciation, amortization and accretion		—		-742			-8,842		—		-9,584
Research and development		—		-2,497			-6,432		—		-8,929
Operating (loss) income		-29		-40,650			1,110		—		-39,569
Other (expense) income:
Other (expense) income		—		-68			11		—		-57
Foreign exchange (losses) gains, net		—		-3			1,913		—		1,910
Interest expense, net		-2,920		-1,076			-1,273		—		-5,269
Interest income (expense) from intercompany notes		453		-324			-129		—		—
Equity (loss) earnings from consolidated subsidiaries		-16,395		4,090			—		12,305		—
		-18,862		2,619			522		12,305		-3,416
(Loss) income before income taxes and equity earnings		-18,891		-38,031			1,632		12,305		-42,985
Income tax benefit		—		23,537			5,419		—		28,956
Equity in results of affiliates		—		-682			20		—		-662
(Loss) income from continuing operations		-18,891		-15,176			7,071		12,305		-14,691
Loss from discontinued operations, net of tax		—		—			-760		—		-760
Net (loss) income		-18,891		-15,176			6,311		12,305		-15,451
Net income attributable to noncontrolling interest		—		—			-3,440		—		-3,440
Net (loss) income attributable to Molycorp stockholders	$	-18,891	$	-15,176		$	2,871	$	12,305	$	-18,891
Net (loss) income	$	-18,891	$	-15,176		$	6,311	$	12,305	$	-15,451
Other comprehensive (loss) income:
Foreign currency translation adjustments		—		—			526		—		526
Comprehensive (loss) income	$	-18,891	$	-15,176		$	6,837	$	12,305	$	-14,925
Comprehensive (loss) income attributable to:
Molycorp stockholders		-18,891		-15,176			10,277		12,305		-11,485
Noncontrolling interest		—		—			-3,440		—		-3,440
	$	-18,891	$	-15,176		$	6,837	$	12,305	$	-14,925
	Nine months ended September 30, 2012
	(In thousands)
Condensed Consolidating Statements of Operations and			Guarantor			Non-Guarantor				Molycorp, Inc.
Comprehensive Loss	Parent		Subsidiaries			Subsidiaries		Eliminations		consolidated
	(Revised)
Revenues	$	—	$	121,172		$	293,228	$	-20,315	$	394,085
Costs of sales:
Costs excluding depreciation and amortization		—		-105,185			-251,784		20,315		-336,654
Depreciation and amortization		—		-7,539			-11,526		—		-19,065
Gross profit		—		8,448			29,918		—		38,366
Operating expenses:
Selling, general and administrative		45		-62,746			-15,882		—		-78,583
Corporate development		-46		-19,333			—		—		-19,379
Depreciation, amortization and accretion		—		-1,441			-10,747		—		-12,188
Research and development		—		-10,584			-8,044		—		-18,628
Operating loss		-1		-85,656			-4,755		—		-90,412
Other (expense) income:
Other (expense) income		-37,589		27			-53		—		-37,615
Foreign exchange (losses) gains, net		—		-5			729		—		724
Interest expense, net		-12,602		-194			-2,193		—		-14,989
Interest income (expense) from intercompany notes		1,326		-967			-359		—		—
Equity loss from consolidated subsidiaries		-55,770		-18,302			—		74,072		—
		-104,635		-19,441			-1,876		74,072		-51,880
Loss before income taxes and equity earnings		-104,636		-105,097			-6,631		74,072		-142,292
Income tax benefit		14,660		37,302			6,480		—		58,442
Equity in results of affiliates		—		-1,475			329		—		-1,146
(Loss) income from continuing operations		-89,976		-69,270			178		74,072		-84,996
Loss from discontinued operations, net of tax		—		—			-860		—		-860
Net loss		-89,976		-69,270			-682		74,072		-85,856
Net income attributable to noncontrolling interest		—		—			-4,120		—		-4,120
Net loss attributable to Molycorp stockholders	$	-89,976	$	-69,270		$	-4,802	$	74,072	$	-89,976
Net loss	$	-89,976	$	-69,270		$	-682	$	74,072	$	-85,856
Other comprehensive loss:
Foreign currency translation adjustments		—		—			-1,165		—		-1,165
Comprehensive loss	$	-89,976	$	-69,270		$	-1,847	$	74,072	$	-87,021
Comprehensive (loss) income attributable to:
Molycorp stockholders		-89,976		-69,270			2,273		74,072		-82,901
Noncontrolling interest		—		—			-4,120		—		-4,120
	$	-89,976	$	-69,270		$	-1,847	$	74,072	$	-87,021
	Nine months ended September 30, 2013
	(In thousands)
			Guarantor			Non-Guarantor				Molycorp, Inc.
Condensed Consolidating Statements of Cash Flows	Parent		Subsidiaries			Subsidiaries		Eliminations		consolidated
Net cash (used in) provided by operating activities	$	-2,990	$	-79,888		$	-7,135	$	—	$	-90,013
Cash flows from investing activities:
Loans to guarantor		—		—			-40,000		40,000		—
Loans to parent		—		—			-12,800		12,800		—
Intercompany advances made		-438,374		—			—		438,374		—
Loans to non-guarantor		—		-1,300			—		1,300		—
Repayments of notes receivable from non-guarantor		38,000		264			—		-38,264		—
Investment in joint ventures		—		-3,423			—		—		-3,423
Capital expenditures		—		-320,829			-13,768		—		-334,597
Other investing activities		—		—			-364		—		-364
Net cash used in investing activities		-400,374		-325,288			-66,932		454,210		-338,384
Cash flows from financing activities:
Repayments of debt		—		—			-25,990		—		-25,990
Net proceeds from sale of common stock		248,150		—			—		—		248,150
Issuance of 5.50% Convertible Notes		165,600		—			—		—		165,600
Payments of preferred dividends		-8,539		—			—		—		-8,539
Dividend paid to noncontrolling interests		—		—			-4,472		—		-4,472
Borrowings from non-guarantor		12,800		40,000			—		-52,800		—
Borrowing from guarantor		—		—			1,300		-1,300		—
Repayments to parent		—		—			-38,000		38,000		—
Repayments to guarantor		—		—			-264		264		—
Intercompany advances owed		—		356,867			81,507		-438,374		—
Other financing activities		—		-797			—		—		-797
Net cash provided by (used in) financing activities		418,011		396,070			14,081		-454,210		373,952
Effect of exchange rate changes on cash		—		—			569		—		569
Net change in cash and cash equivalents		14,647		-9,106			-59,417		—		-53,876
Cash and cash equivalents at beginning of the period		16,560		18,020			193,210		—		227,790
Cash and cash equivalents at end of period	$	31,207	$	8,914		$	133,793	$	—	$	173,914
	Nine months ended September 30, 2012
	(In thousands)
			Guarantor			Non-Guarantor				Molycorp, Inc.
	Parent		Subsidiaries			Subsidiaries		Eliminations		consolidated
Condensed Consolidating Statements of Cash Flows	(Revised)
Net cash (used in) provided by operating activities	$	-20,495	$	-57,987		$	31,294	$	—	$	-47,188
Cash flows from investing activities:
Loans to subsidiaries		-683,063		—			—		683,063		—
Loans to parent		—		-37,589					37,589		—
Intercompany advances made		-792,709		—			—		792,709		—
Repayments from subsidiaries		34,327		—			—		-34,327		—
Investment in subsidiaries		-350,000		—			—		350,000		—
Notes receivable to non-guarantor		—		-227,512			—		227,512		—
Repayments of notes receivable from non-guarantor		—		100,000			—		-100,000		—
Cash paid in connection with acquisitions, net of cash acquired		—		—			-591,011		—		-591,011
Investment in joint ventures		—		-28,130			—		—		-28,130
Deposits		—		-516			—		—		-516
Capital expenditures		—		-628,407			-16,276		—		-644,683
Other investing activities		—		—			4,953		—		4,953
Net cash used in investing activities		-1,791,445		-822,154			-602,334		1,956,546		-1,259,387
Cash flows from financing activities:
Capital contributions from stockholder		390,225		—			—		—		390,225
Contribution from parent		—		—			350,000		-350,000		—
Proceeds from debt		—		—			9,456		—		9,456
Repayments of debt		—		-870			-227,561		—		-228,431
Net proceeds from sale of common stock		132,471		—			—		—		132,471
Net proceeds from sale of Senior Notes		635,373		—			—		—		635,373
Issuance of 6.00% Convertible Notes		395,712		—			—		—		395,712
Payments of preferred dividends		-8,539		—			—		—		-8,539
Borrowing from parent		—		227,512			455,551		-683,063		—
Borrowing from guarantor		37,589		—			227,512		-265,101		—
Repayments to parent		—		-34,327			—		34,327		—
Intercompany advances owed		—		680,966			111,743		-792,709		—
Repayments of borrowing to guarantor		—		—			-100,000		100,000		—
Other financing activities		-2,937		-68			-326		—		-3,331
Net cash provided by financing activities		1,579,894		873,213			826,375		-1,956,546		1,322,936
Effect of exchange rate changes on cash		—		—			809		—		809
Net change in cash and cash equivalents		-232,046		-6,928			256,144		—		17,170
Cash and cash equivalents at beginning of the period		407,446		10,758			651		—		418,855
Cash and cash equivalents at end of period	$	175,400	$	3,830		$	256,795	$	—	$	436,025
At December 31, 2012, a classification error in the previously presented subsidiary guarantor cash flows statements for the nine months ended September 2012 was identified for advances received by Guarantor and Non-Guarantor Subsidiaries from the Parent. To correct the error, the Company determined a change in the presentation of advances received by the Guarantor and Non-Guarantor Subsidiaries was required to present borrowings from the Parent to the Guarantor of $681.0 million, and from the Parent to the Non-Guarantor Subsidiaries of $111.7 million, as a financing activity in their cash flows statements, rather than as an investing activity as previously presented to conform to the guidance outlined in ASC 230. This guidance states that proceeds from borrowings should be reflected as a financing activity. The impact of these revisions is not material to the related financial statements taken as a whole. The revised change in presentation to appropriately reflect these borrowings as financing activities for the nine months ended September 2012 is outlined below.
	Nine months ended September 30, 2012
	As reported		Adjustment		Revised
Guarantor Subsidiaries	(In thousands of dollars)
Intercompany advances made		680,966	-680,966		—
Loans to parent		—	-37,589		-37,589
Net cash used in investing activities		-103,599	-718,555		-822,154
Intercompany advances owed		—	680,966		680,966
Net cash provided by financing activities		192,247	680,966		873,213
Non-Guarantor Subsidiaries
Intercompany advances made		111,743	-111,743		—
Net cash used in investing activities		-490,591	-111,743		-602,334
Intercompany advances owed		—	111,743		111,743
Net cash provided by financing activities		714,632	111,743		826,375
In this Form 10-Q, the Company also corrected a classification error in the previously presented subsidiary guarantor statements of operations and comprehensive loss for the nine months ended September 30, 2012 between Parent and Guarantor Subsidiaries related to the loss of $37.6 million recognized upon settlement on June 11, 2012 of the contingent forward contract the Company entered into in connection with the Molycorp Canada acquisition. See Note 23 for further details on this contingent forward contract. In the Form 8-K filed on November 21, 2012, which contained the subsidiary guarantor information for the nine months ended September 30, 2012 in the Exhibit 99.1, the loss of $37.6 million was presented under the Guarantor Subsidiaries because the cash to settle the loss was wired from a bank account of Molycorp Minerals LLC, which is one of the Guarantor Subsidiaries. However, since the cash to settle the contingent forward contract was actually funded by Molycorp, Inc., or Parent, through an intercompany transaction, and Parent was the party that signed the contingent forward contract, the loss should be presented under Parent. The correction of this classification error also had an impact on the presentation of the income tax benefit, deferred taxes, income tax payable and cash flows from operating, investing and financing activities within the subsidiary guarantor financial information. The impact of these revisions is not material to the Company's financial statements taken as a whole. The table below illustrates the changes in the presentation of the subsidiary guarantor financial information in 2012 to correctly reflect the forward contract loss between Parent and Guarantor Subsidiaries.
	Nine months ended September 30, 2012
	As reported		Adjustment		Revised
Parent	(In thousands of dollars)
Other expense		—	-37,589		-37,589
Equity loss from consolidated subsidiaries		-78,699	22,929		-55,770
Loss before income taxes and equity earnings		-89,976	-14,660		-104,636
Income tax benefit		—	14,660		14,660
Net cash provided by (used in) operating activities		17,094	-37,589		-20,495
Borrowing from guarantor		—	37,589		37,589
Net cash provided by financing activities		1,542,305	37,589		1,579,894
Guarantor Subsidiaries
Other (expense) income		-37,562	37,589		27
Loss before income taxes and equity earnings		-142,686	37,589		-105,097
Income tax benefit		51,962	-14,660		37,302
Loss from continuing operations		-92,199	22,929		-69,270
Net cash (used in) provided by operating activities		-95,576	37,589		-57,987
Loans to parent		—	-37,589		-37,589
Intercompany advances made		680,966	-680,966		—
Net cash used in investing activities		-103,599	-718,555		-822,154

Discontinued_Operations

Discontinued Operations	9 Months Ended
	Sep. 30, 2013
Discontinued Operations [Abstract]	'
Discontinued Operations	'
	(26)Discontinued Operations
	In July 2013, the Company committed to a plan to discontinue operations at its Napanee facility by the end of fiscal 2013 due to a declining demand for rhenium combined with unfavorable operating costs in this particular recycling sector. The facility, which consists of two buildings on approximately two acres, specializes on the recycling of rhenium bearing scrap within the Rare Metals segment. In addition to the land and the buildings, the disposal group includes hydrometallurgical recovery equipment and rhenium inventory. As of September 30, 2013, the disposal group had the following carrying amounts, which are recorded under “Prepaid expenses and other current assets” in the condensed consolidated balance sheet:
		September 30,
		2013
		(In thousands)
	Land	$	50
	Buildings		700
	Equipment		750
	Inventory		819
	Carrying value of disposal group	$	2,319
	The following table summarizes the operating results of the Napanee facility included in discontinued operations for the three and nine months ended September 30, 2013 and 2012:
		Three Months Ended September 30,				Nine Months Ended September 30,
		2013		2012		2013		2012
			(In thousands)
	Revenues	$	216	$	399	$	1,931	$	566
	Costs of sales		-913		-901		-3,044		-1,115
	Selling, general and administrative expenses		-34		-119		-307		-138
	Depreciation		—		-139		-315		-173
	Operating loss		-731		-760		-1,735		-860
	Loss on assets impairment		-3,455		—		-3,455		—
	Income tax		—		—		—		—
	Net loss	$	-4,186	$	-760	$	-5,190	$	-860

Recent_Accounting_Pronouncemen

Recent Accounting Pronouncements	9 Months Ended
	Sep. 30, 2013
Recent Accounting Pronouncements [Abstract]	'
Recent Accounting Pronouncements	'
	(27)Recent Accounting Pronouncements
	In February 2013, the Financial Accounting Standard Board ("FASB") issued ASU 2013-02, Comprehensive Income (Topic 220), Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income. This update requires companies to report, in one place, information about reclassifications out of accumulated other comprehensive income ("AOCI"). Companies also are required to present reclassifications by component when reporting changes in AOCI balances. For significant items reclassified out of AOCI to net income in their entirety in the period, companies must report the effect of the reclassifications on the respective line items in the statement where net income is presented. In certain circumstances, this can be done on the face of that statement. Otherwise, it must be presented in the notes. For items not reclassified to net income in their entirety in the period (e.g., pension amounts that are capitalized in inventory), companies must cross-reference in a note to other required disclosures. This update was effective for public companies in fiscal years, and interim periods within those years, beginning after December 15, 2012. The adoption of this updated guidance did not have any impact on the Company's financial statements and related disclosures.
	In July 2012, the FASB issued ASU 2012-02, Intangibles - Goodwill and Other (Topic 350), Testing Indefinite-Lived Intangible Assets for Impairment. In accordance with this update, an entity has the option first to assess qualitative factors to determine whether the existence of events and circumstances indicates that it is more likely than not that the indefinite-lived intangible asset is impaired. If, after assessing the totality of events and circumstances, an entity concludes that it is not more likely than not that the indefinite-lived intangible asset is impaired, then the entity is not required to take further action. However, if an entity concludes otherwise, then it is required to determine the fair value of the indefinite-lived intangible asset and perform the quantitative impairment test by comparing the fair value with the carrying amount and record an impairment charge, if any. This update was effective for annual and interim period impairment tests performed for fiscal years beginning after September 15, 2012. Early adoption was permitted. The adoption of this updated guidance did not have any impact on the Company's financial statements and related disclosures.

Subsequent_Events

Subsequent Events	9 Months Ended
	Sep. 30, 2013
Subsequent Events [Abstract]	'
Subsequent Events	'
	(28)Subsequent Events
	Preferred stock dividend
	In November 2013, the Company declared a cash dividend of $1.375 per share on the Convertible Preferred Stock to be paid on December 1, 2013 to holders of record at the close of business on November 15, 2013.
	Public Offering
	On October 21, 2013, the Company completed a public offering of 51,750,000 shares of its common stock, which included the issuance of 6,750,000 shares as a result of the underwriters’ exercise in full of their option to purchase additional shares in the offering, at a price per share of $5.00. The issuance of these shares resulted in net proceeds to the Company, after fees and expenses payable by the Company, of approximately $247.5 million. The Company intends to use the net proceeds received from the offering, as well as cash generated from operations, to fund current needs for capital expenditures and other cash requirements, including, without limitation, capital expenditures at the Molycorp Mountain Pass facility.
	Significant Shareholder Agreement
	On October 14, 2013, the Company entered into a funding agreement with Molibdenos y Metales S.A. ("Molymet") pursuant to which Molymet agreed that, at the request of the Company during the term of the agreement, Molymet would purchase $50.0 million of the Company’s common stock. The Company did not make such a request and the agreement with Molymet expired by its terms on October 28, 2013.

Segment_Information_Tables

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2013
Segment Information [Abstract]	'
Schedule Of Segment Information	'
					Magnetic
				Chemicals and	Materials and		Corporate and		Total Molycorp,
	Three months ended September 30, 2013		Resources	Oxides	Alloys	Rare Metals	other(a)	Eliminations(b)	Inc.
	Revenues:		(In thousands of dollars)
	External		4,655	50,791	72,626	20,994		—	149,066
	Intersegment		8,858	7,174	—	—		-16,032	—
	Total revenues		13,513	57,965	72,626	20,994		-16,032	149,066
	Depreciation, amortization and accretion		-10,853	-5,960	-7,458	-2,144	-57	—	-26,472
	Operating (loss) income		-55,526	-1,399	11,062	-3,055	-10,806	723	-59,001
	(Loss) income before income taxes and equity earnings		-56,139	-1,527	39,291	-4,807	-53,722	723	-76,181
	Total assets at September 30, 2013		1,880,127	567,207	621,127	100,794	1,329,485	-1,471,464	3,027,276
	Capital expenditures (c)		57,637	1,573	1,457	1,946	77	—	62,690
					Magnetic
				Chemicals and	Materials and		Corporate and		Total Molycorp,
	Three months ended September 30, 2012		Resources	Oxides	Alloys	Rare Metals	other(a)	Eliminations(b)	Inc.
	Revenues:		(In thousands of dollars)
	External		17,150	87,820	74,789	25,446		—	205,205
	Intersegment		3,745	11,559	—	—		-15,304	—
	Total revenues		20,895	99,379	74,789	25,446		-15,304	205,205
	Depreciation, amortization and accretion		-4,035	-5,685	-8,857	-1,576	-43	—	-20,196
	Operating (loss) income		-23,966	2,149	1,419	-3,014	-16,526	369	-39,569
	(Loss) income before income taxes and equity earnings		-25,506	1,201	1,215	-3,052	-17,212	369	-42,985
	Capital expenditures (c)		187,611	2,597	1,432	2,837	1,387	—	195,864
					Magnetic
				Chemicals and	Materials and		Corporate and		Total Molycorp,
	Nine months ended September 30, 2013		Resources	Oxides	Alloys	Rare Metals	other(a) (d)	Eliminations(b)	Inc.
	Revenues:		(In thousands of dollars)
	External		30,235	135,180	193,417	71,748		—	430,580
	Intersegment		18,168	28,476	—	—		-46,644	—
	Total revenues		48,403	163,656	193,417	71,748		-46,644	430,580
	Depreciation, amortization and accretion		-31,536	-17,087	-20,360	-6,402	-171	—	-75,556
	Operating (loss) income		-136,055	-19,879	28,463	-2,455	-32,321	-1,101	-163,348
	(Loss) income before income taxes and equity earnings		-135,047	-18,438	67,089	57	-116,241	-1,101	-203,681
	Capital expenditures (c)		205,669	5,672	2,910	5,595	244	—	220,090
					Magnetic
				Chemicals and	Materials and		Corporate and		Total Molycorp,
	Nine months ended September 30, 2012		Resources	Oxides	Alloys	Rare Metals	other(a) (d)	Eliminations(b)	Inc.
	Revenues:
	External		78,162	134,158	125,277	56,488		—	394,085
	Intersegment		5,977	15,496	—	—		-21,473	—
	Total revenues		84,139	149,654	125,277	56,488		-21,473	394,085
	Depreciation, amortization and accretion		-8,743	-7,419	-10,810	-4,185	-96	—	-31,253
	Operating income (loss)		-23,594	-21,863	-1,544	-1,087	-66,804	24,480	-90,412
	(Loss) income before income taxes and equity earnings		-25,044	-23,663	-2,381	-2,138	-113,546	24,480	-142,292
	Capital expenditures (c)		675,836	6,615	1,612	6,955	1,733	—	692,751
	(a)	Corporate loss before income taxes and equity earnings includes business development costs, personnel and related costs, including stock-based compensation expense, accounting and legal fees, occupancy expense, information technology costs and interest expense. Total corporate assets is comprised primarily of cash and cash equivalents.
	(b)	The net elimination in operating results includes costs of sales eliminations of $16,755 and $45,543 for the three and nine months ended September 30, 2013, respectively; $15,673 and $45,952 for the three and nine months ended September 30, 2012, respectively. Costs of sales eliminations consist of intercompany gross profits as well as eliminations of lower of cost or market adjustments related to intercompany inventory. The total assets elimination is comprised primarily of intercompany investments and intercompany accounts receivable and profits in inventory.
	(c)	On an accrual basis excluding capitalized interest.
	(d)	The Corporate segment included severance charges of $2,100 for the nine months ended September 30, 2013. See Note 24 for details.

Inventory_Tables

Inventory (Tables)	9 Months Ended
	Sep. 30, 2013
Inventory [Abstract]	'
Schedule Of Inventory	'
		September 30,		December 31,
		2013		2012
	Current:	(In thousands)
	Concentrate stockpiles	$	660	$	6,393
	Raw materials		58,269		95,248
	Work-in-process		41,797		55,229
	Finished goods		61,601		114,903
	Materials and supplies		21,114		15,603
	Total current	$	183,441	$	287,376
	Long-term:
	Concentrate stockpiles	$	4	$	4
	Raw materials		24,321		26,092
	Total long-term	$	24,325	$	26,096

Property_Plant_And_Equipment_N1

Property, Plant And Equipment, Net (Tables)	9 Months Ended
	Sep. 30, 2013
Property, Plant And Equipment, Net [Abstract]	'
Schedule Of Property, Plant And Equipment	'
		September 30,		December 31,
		2013		2012
		(In thousands)
	Land	$	12,678	$	12,475
	Land improvements		68,903		63,269
	Buildings and improvements		404,436		237,379
	Plant and equipment		290,678		194,934
	Vehicles		2,942		2,842
	Computer software		12,254		9,528
	Furniture and fixtures		1,044		1,116
	Construction in progress (a)		1,010,173		1,011,541
	Natural gas delivery facility under capital lease		15,658		15,658
	Mining equipment under capital lease		5,992		—
	Mineral properties		24,115		24,327
	Exploration rights		16,170		16,166
	Property, plant and equipment at cost		1,865,043		1,589,235
	Less accumulated depreciation		-85,959		-44,931
	Property, plant and equipment, net	$	1,779,084	$	1,544,304
	(a)	Represents costs incurred at the Molycorp Mountain Pass facility and all other capital projects. See Note 2.

Goodwill_And_Other_Intangible_1

Goodwill And Other Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2013
Goodwill And Other Intangible Assets [Abstract]	'
Schedule Of Goodwill	'
						Additional		September 30,
		December 31, 2012				impairment		2013
		Reported		Adjustment
		(In thousands)
	Chemicals and Oxides	$	125,229	$	16,132	$	-16,132	$	125,229
	Magnetic Materials and Alloys		102,808		16,716		-16,716		102,808
	Rare Metals		11,705		-1,232		1,232		11,705
	Total	$	239,742	$	31,616	$	-31,616	$	239,742
Schedule Of Amortizable Intangible Assets	'
		Customer		Rare earth						Land use
		relationships		quotas		Patents		Trade names		rights		Other		Total
	Gross carrying amount	(In thousands)
	At December 31, 2012	$	344,774		78,300		33,252	$	15,586		3,568		4,420	$	479,900
	Additions		48												48
	Foreign currency translation adjustment		-262		—		—		—		—		—		-262
	At September 30, 2013	$	344,560	$	78,300	$	33,252	$	15,586	$	3,568	$	4,420	$	479,686
	Amortization
	At December 31, 2012	$	14,095		4,035		9,365	$	1,152		66		249	$	28,962
	Adjustments		-269		—		—		-873		—		—		-1,142
	Amortization		16,395		5,238		10,131		49		121		461		32,395
	At September 30, 2013		30,221		9,273		19,496		328		187		710		60,215
	Net book value	$	314,339	$	69,027	$	13,756	$	15,258	$	3,381	$	3,710	$	419,471

Acquisitions_Tables

Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2013
Acquisitions [Abstract]	'
Summarizes The Purchase Prices And Opening Balance Sheets For The Acquisitions	'
		Preliminary
		Allocation of
		Consideration
		Transferred as of		Measurement		Final Allocation of
		December 31,		Period		Consideration
		2012		Adjustments		Transferred
	Purchase consideration:	(In thousands)
	Cash consideration	$	908,181			$	908,181
	Fair value of Molycorp common stock and Exchangeable Shares issued		284,144				284,144
	Total purchase consideration	$	1,192,325			$	1,192,325
	Estimated fair values of the assets and liabilities acquired:
	Cash and cash equivalents	$	317,169	$	—	$	317,169
	Restricted cash		4,951		—		4,951
	Accounts receivable		101,470		—		101,470
	Inventory		250,989		—		250,989
	Prepaid expenses and other current assets		26,893		—		26,893
	Property, plant and equipment		75,745		—		75,745
	Investments		21,019		-1,091		19,928
	Intangibles		482,234		—		482,234
	Deferred tax charges		13,435		—		13,435
	Deferred tax assets		11,473		-1,423		10,050
	Goodwill		494,809		31,616		526,425
	Other non-current assets		4,367		—		4,367
	Accounts payable and accrued expenses		-138,576		—		-138,576
	Debt		-255,338		—		-255,338
	Other current liabilities		-33,990		—		-33,990
	Deferred tax liabilities		-154,309		5,880		-148,429
	Other non-current liabilities		-14,255		—		-14,255
	Non-controlling interests		-15,761		-34,982		-50,743
	Total purchase consideration	$	1,192,325	$	—	$	1,192,325
Summary Of Actual And Pro Forma Information	'
						Net loss
						Attributable To Molycorp.
						Attributable To
	(In thousands, except per share amounts)	Revenues		Net Loss		Molycorp		Loss per share
	Unaudited pro forma January 1, 2012 to September 30, 2012 (combined entity)	$	729,469	$	-74,229	$	-82,056	$	-0.77

Accrued_Expenses_Tables

Accrued Expenses (Tables)	9 Months Ended
	Sep. 30, 2013
Accrued Expenses [Abstract]	'
Schedule Of Accrued Expenses	'
		September 30,		December 31,
		2013		2012
		(In thousands)
	Defined contribution plan	$	1,440	$	1,400
	Professional fees		133		4,971
	Accrued payroll and related benefits		7,254		7,532
	Sales and use tax		1,768		7,187
	Bonus accrual		3,846		3,503
	Interest payable		28,076		15,253
	Advance from customer		80		1,753
	Withholding taxes		3,433		2,929
	Amount payable to noncontrolling shareholder		6,211		9,640
	Other accrued expenses		9,204		4,845
	Total accrued expenses	$	61,445	$	59,013

Asset_Retirement_Obligation_Ta

Asset Retirement Obligation (Tables)	9 Months Ended
	Sep. 30, 2013
Asset Retirement Obligation [Abstract]	'
Schedule Of Activity In Asset Retirement Obligation	'
		Nine months
		ended		Year Ended
		September 30,		December 31,
		2013		2012
		(In thousands)
	Balance at beginning of period	$	22,125	$	15,541
	Obligations settled		-2,384		-2,954
	Accretion expense		1,032		1,299
	Revisions in estimated cash flows		—		7,872
	Loss on settlement		—		367
	Balance at end of period	$	20,773	$	22,125

Debt_And_Capital_Lease_Obligat1

Debt And Capital Lease Obligations (Tables)	9 Months Ended
	Sep. 30, 2013
Debt And Capital Lease Obligations [Abstract]	'
Schedule Of Long-Term Debt Instruments	'
		September 30, 2013				31-Dec-12
		Current		Non-Current		Current		Non-Current
		(In thousands)
	Bank loans due November 2013 - September 2017	$	14,812	$	3,072	$	39,252	$	4,118
	3.25% Convertible Notes, net of discount, due June 2016		—		204,903		—		198,689
	6.00% Convertible Notes, net of discount, due September 2017		—		342,883		—		331,977
	5.00% Debentures, net of discount, due December 2017		—		2,495		—		2,774
	5.50% Convertible Notes, net of discount, due February 2018		—		146,961		—		—
	10% Senior Secured Notes, net of discount, due June 2020		—		637,092		—		636,111
	Total debt		14,812		1,337,406		39,252		1,173,669
	Capital lease obligations		1,861		18,850		352		15,163
	Total debt and capital lease obligations	$	16,673	$	1,356,256	$	39,604	$	1,188,832
Schedule Of Long-Term Debt Conversions	'
		3.25% Convertible Notes				6.00% Convertible Notes				5.50% Convertible Notes
		At September 30,		At December 31,		At September 30,		At December 31,		At September 30,		At December 31,
		2013		2012		2013		2012		2013		2012
		(In thousands of dollars)
	Liability component (a)		201,905		196,702		339,304		330,177		146,166	n/a
	Equity component		36,251		36,251		68,695		68,695		21,815	n/a
		Three months ended September 30,
		2013		2012		2013		2012		2013		2012
	Accretion of liability component		1,772		1,651		2,888		1,147		918	n/a
	Interest cost (b)		3,988		3,854		9,969		7,740		3,609	n/a
	Capitalized interest		2,373		3,439		5,891		3,493		2,148	n/a
		Nine months ended September 30,
		2013		2012		2013		2012		2013		2012
	Accretion of liability component		5,203		4,849		8,491		1,147		2,382	n/a
	Interest cost (b)		11,839		11,446		29,691		7,740		9,482	n/a
	Capitalized interest		7,178		10,598		17,959		3,493		5,678	n/a
	(a) The liability component is the difference between the net proceeds and the equity component of a convertible note that can be settled in a combination of cash and shares of stock at the election of the issuer. The equity component represents the conversion feature of a convertible note and is treated as original issue discount in addition to the underwriting discount. The liability component includes the periodic amortization of the additional discount.
	(b) Interest cost includes the coupon interest, the accretion of the liability component, the accretion of the underwriting discount and the amortization of the issuance costs allocated to the liability component.

Loss_Per_Share_Tables

Loss Per Share (Tables)	9 Months Ended
	Sep. 30, 2013
Loss Per Share [Abstract]	'
Schedule Of Earnings Per Share, Basic And Diluted	'
		Three Months Ended September 30,				Nine Months Ended September 30,
	(In thousands, except share and per share amounts)	2013		2012		2013		2012
	Net loss attributable to Molycorp stockholders:	$	-69,929	$	-18,891	$	-180,072	$	-89,976
	Dividends on Convertible Preferred Stock		-2,846		-2,846		-8,539		-8,539
	Loss attributable to common stockholders		-72,775		-21,737		-188,611		-98,515
	Continuing operations		-68,589		-20,977		-183,421		-97,655
	Discontinued operations		-4,186		-760		-5,190		-860
		$	-72,775	$	-21,737	$	-188,611	$	-98,515
	Weighted average common shares outstanding—basic		168,114,266		117,086,022		163,222,000		101,147,638
	Basic loss per share:
	Continuing operations	$	-0.41	$	-0.18	$	-1.12	$	-0.97
	Discontinued operations		-0.02		-0.01		-0.03		-0.01
		$	-0.43	$	-0.19	$	-1.16	$	-0.97
	Diluted loss per share:
	Continuing operations	$	-0.41	$	-0.18	$	-1.12	$	-0.97
	Discontinued operations		-0.02		-0.01		-0.03		-0.01
		$	-0.43	$	-0.19	$	-1.16	$	-0.97

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Summary Of The Activity And Other Information Related To Stock Option Awards	'
			Weighted
			Average
		Number of	Grant-Date
	Stock Options	Shares	Price
	Outstanding at January 1, 2013	35,624	$	48.87
	Granted	—		—
	Exercised	—		—
	Forfeited and expired	-9,008	$	48.87
	Outstanding at September 30, 2013	26,616	$	48.87
	Options exercisable at September 30, 2013	17,744	$	48.87
PBRSUs [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Summary Of Activity Related To Stock-Based Awards	'
			Weighted
			Average
		Number of	Grant-Date
	PBRSUs	Shares	Price
	Unvested at January 1, 2013	29,302	$	30.33
	Granted	897,515	$	6.76
	Forfeited	-65,143	$	11.17
	Vested	—		—
	Unvested at September 30, 2013	861,674	$	7.23
RSUs [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Summary Of Activity Related To Stock-Based Awards	'
			Weighted
			Average
		Number of	Grant-Date
	RSUs	Shares	Price
	Unvested at January 1, 2013	181,602	$	32.15
	Granted	997,979	$	7.04
	Forfeited	-80,510	$	28.06
	Vested*	-19,632	$	7.56
	Unvested at September 30, 2013	1,079,439	$	9.82
	*  Includes deferral and conversion of a portion of fees payable to certain non-employee directors of the Company.
Restricted Stock [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Summary Of Activity Related To Stock-Based Awards	'
			Weighted
			Average
		Number of	Grant-Date
	RSAs	Shares	Price
	Unvested at January 1, 2013	39,974	$	40.09
	Granted	—		—
	Forfeited	-8,143	$	39.76
	Vested	—		—
	Unvested at September 30, 2013	31,831	$	37.87

Commitments_And_Contingencies_

Commitments And Contingencies (Tables)	9 Months Ended
	Sep. 30, 2013
Commitments And Contingencies [Abstract]	'
Schedule Of Future Minimum Rental Payments For Operating Leases	'
				Less Than 1						More Than 5
		Total		Year		1 - 3 Years		4 - 5 Years		Years
		(In thousands)
	Operating lease obligations	$	6,966	$	2,667	$	2,824	$	437	$	1,038
Schedule Of Minimum Payments For Purchase Obligations	'
				Less Than 1						More Than 5
		Total		Year		1 - 3 Years		4 - 5 Years		Years
		(In thousands)
	Purchase obligations and other commitment	$	251,361	$	227,365	$	13,206	$	6,487	$	4,303

Net_Change_In_Operating_Assets1

Net Change In Operating Assets And Liabilities (Tables)	9 Months Ended
	Sep. 30, 2013
Net Change In Operating Assets And Liabilities [Abstract]	'
Schedule Of Changes In Operating Assets And Liabilities, Net Of The Effects Of Acquisitions And Dispositions	'
		Nine Months Ended September 30,
		2013		2012
		(In thousands)
	Decrease (increase) in operating assets:
	Accounts receivable	$	-5,557	$	88,997
	Inventory		26,816		13,202
	Prepaid expenses and other assets		-1,085		7,174
	Increase (decrease) in operating liabilities:
	Accounts payable		-16,642		-43,223
	Income tax payable		-8,768		-39,483
	Interest payable		-26,765		-9,704
	Asset retirement obligation		-2,385		—
	Accrued expenses		-10,826		-49,044
		$	-45,212	$	-32,081

Employee_Benefit_Plans_And_Sev1

Employee Benefit Plans And Severance Charges (Tables)	9 Months Ended
	Sep. 30, 2013
Employee Benefit Plans And Severance Charges [Abstract]	'
Schedule Of Net Benefit Costs	'
	Three Months Ended September 30, 2013	Pension Plan		PBP		Total
		(In thousands)
	Components of net periodic benefit cost:
	Service Cost	$	—	$	—	$	—
	Interest cost		78		2		80
	Expected return on plan assets		-68		—		-68
	Amortization of transition obligation/(asset)		—		—		—
	Amortization of prior service cost		—		-1		-1
	Amortization of actuarial loss		63		-2		61
	Net periodic benefit cost	$	73	$	-1	$	72
	Nine Months Ended September 30, 2013	Pension Plan		PBP		Total
		(In thousands)
	Components of net periodic benefit cost:
	Service Cost	$	—	$	—	$	—
	Interest cost		234		6		240
	Expected return on plan assets		-203		—		-203
	Amortization of transition obligation/(asset)		—		—		—
	Amortization of prior service cost		—		-3		-3
	Amortization of actuarial loss		189		-6		183
	Net periodic benefit cost	$	220	$	-3	$	217

Subsidiary_Guarantor_Financial1

Subsidiary Guarantor Financial Information (Tables)	9 Months Ended
	Sep. 30, 2013
Subsidiary Guarantor Financial Information [Abstract]	'
Schedule Of Condensed Balance Sheet	'
		At September 30, 2013
		(In thousands)
				Guarantor			Non-Guarantor				Molycorp, Inc.
	Condensed Consolidating Balance Sheets	Parent		Subsidiaries			Subsidiaries		Eliminations		consolidated
	Current assets:
	Cash and cash equivalents	$	31,207	$	8,914		$	133,793	$	—	$	173,914
	Trade accounts receivable, net		—		3,012			55,188		—		58,200
	Inventory		—		34,044			149,397		—		183,441
	Deferred charges		—		1,329			1,751		—		3,080
	Deferred tax assets		—		—			8,478		—		8,478
	Income tax receivable		—		20,243			53		—		20,296
	Prepaid expenses and other current assets		—		9,559			16,101		—		25,660
	Total current assets		31,207		77,101			364,761		—		473,069
	Non-current assets:
	Deposits		1,754		24,243			—		—		25,997
	Property, plant and equipment, net		—		1,620,346			158,738		—		1,779,084
	Inventory		—		24,325			—		—		24,325
	Intangible assets, net		—		459			419,012		—		419,471
	Investments		—		43,425			15,324		—		58,749
	Goodwill		—		—			239,742		—		239,742
	Investments in consolidated subsidiaries		699,379		122,784			—		-822,163		—
	Intercompany accounts receivable		1,920,116		—			791		-1,920,907		—
	Other non-current assets		—		785			6,054		—		6,839
	Total non-current assets		2,621,249		1,836,367			839,661		-2,743,070		2,554,207
	Total assets	$	2,652,456	$	1,913,468		$	1,204,422	$	-2,743,070	$	3,027,276
	Current liabilities:
	Trade accounts payable	$	—	$	70,498		$	37,384	$	—	$	107,882
	Accrued expenses		27,695		12,375			21,375		—		61,445
	Income tax payable		—		7			8,432		-6,731		1,708
	Debt and capital lease obligations		—		1,861			14,812		—		16,673
	Other current liabilities		—		6,689			—		—		6,689
	Total current liabilities		27,695		91,430			82,003		-6,731		194,397
	Non-current liabilities:
	Asset retirement obligation		—		14,084			—		—		14,084
	Deferred tax liabilities		—		—			118,411		6,731		125,142
	Debt and capital lease obligations		1,331,839		18,850			5,567		—		1,356,256
	Derivative liability		—		—			6,819		—		6,819
	Pension liabilities		—		—			3,431		—		3,431
	Intercompany accounts payable		—		1,916,264			4,643		-1,920,907		—
	Other non-current liabilities		—		1,340			712		—		2,052
	Total non-current liabilities		1,331,839		1,950,538			139,583		-1,914,176		1,507,784
	Total liabilities	$	1,359,534	$	2,041,968		$	221,586	$	-1,920,907	$	1,702,181
	Stockholders’ equity:
	Common stock		189		—			—		—		189
	Preferred stock		2		—			—		—		2
	Additional paid-in capital		1,946,742		149,857			1,316,079		-1,465,936		1,946,742
	Accumulated other comprehensive loss		-7,848		—			-7,848		7,848		-7,848
	Accumulated deficit		-646,163		-278,357			-357,568		635,925		-646,163
	Total Molycorp stockholders’ equity		1,292,922		-128,500			950,663		-822,163		1,292,922
	Noncontrolling interests		—		—			32,173		—		32,173
	Total stockholders’ equity		1,292,922		-128,500			982,836		-822,163		1,325,095
	Total liabilities and stockholders’ equity	$	2,652,456	$	1,913,468		$	1,204,422	$	-2,743,070	$	3,027,276
		At December 31, 2012
		(In thousands)
				Guarantor			Non-Guarantor				Molycorp, Inc.
	Condensed Consolidating Balance Sheets	Parent		Subsidiaries			Subsidiaries		Eliminations		consolidated
	Current assets:
	Cash and cash equivalents	$	16,560	$	18,020		$	193,210	$	—	$	227,790
	Trade accounts receivable, net		—		7,738			44,692		—		52,430
	Inventory		—		49,416			237,960		—		287,376
	Deferred charges		—		2,203			7,209		—		9,412
	Deferred tax assets		—		—			11,731		-1,942		9,789
	Income tax receivable		—		25,087			—		—		25,087
Prepaid expenses and other current assets		—		9,085			12,709		—		21,794
Total current assets		16,560		111,549			507,511		-1,942		633,678
Non-current assets:
Deposits		1,752		24,862			155		—		26,769
Property, plant and equipment, net		—		1,377,147			167,157		—		1,544,304
Inventory		—		26,096			—		—		26,096
Intangible assets, net		—		508			450,430		—		450,938
Investments		—		45,241			18,795				64,036
Deferred tax assets		6,030		—			—		-6,030		—
Goodwill		—		—			239,742		—		239,742
Investments in consolidated subsidiaries		883,319		97,960			—		-981,279		—
Intercompany accounts receivable		1,539,877		207,035			794		-1,747,706		—
Other non-current assets		—		885			6,087		—		6,972
Total non-current assets		2,430,978		1,779,734			883,160		-2,735,015		2,358,857
Total assets	$	2,447,538	$	1,891,283		$	1,390,671	$	-2,736,957	$	2,992,535
Current liabilities:
Trade accounts payable	$	—	$	191,769		$	50,225	$	—	$	241,994
Accrued expenses		14,872		10,087			34,054		—		59,013
Income tax payable		—		—			15,267		—		15,267
Deferred tax liabilities		—		1,942			—		-1,942		—
Debt and capital lease obligations		—		352			39,252		—		39,604
Other current liabilities		—		3,539			—		—		3,539
Total current liabilities		14,872		207,689			138,798		-1,942		359,417
Non-current liabilities:
Asset retirement obligation		—		18,586			—		—		18,586
Deferred tax liabilities		—		23,130			143,575		-6,030		160,675
Debt and capital lease obligations		1,166,777		15,163			6,892		—		1,188,832
Derivative liability		—		—			7,816		—		7,816
Pension liabilities		—		—			3,292		—		3,292
Intercompany accounts payable		49,843		1,577,363			120,500		-1,747,706		—
Other non-current liabilities		—		1,102			1,557		—		2,659
Total non-current liabilities		1,216,620		1,635,344			283,632		-1,753,736		1,381,860
Total liabilities	$	1,231,492	$	1,843,033		$	422,430	$	-1,755,678	$	1,741,277
Stockholders’ equity:
Common stock		139		—			—		—		139
Preferred stock		2		—			—		—		2
Additional paid-in capital		1,691,429		149,857			1,283,863		-1,433,720		1,691,429
Accumulated other comprehensive loss		-9,433		—			-9,433		9,433		-9,433
Accumulated deficit		-466,091		-101,607			-341,401		443,008		-466,091
Total Molycorp stockholders’ equity		1,216,046		48,250			933,029		-981,279		1,216,046
Noncontrolling interests		—		—			35,212		—		35,212
Total stockholders’ equity		1,216,046		48,250			968,241		-981,279		1,251,258
Total liabilities and stockholders’ equity	$	2,447,538	$	1,891,283		$	1,390,671	$	-2,736,957	$	2,992,535
Schedule Of Condensed Income Statement And Comprehensive Income	'
		Three months ended September 30, 2013
		(In thousands)
	Condensed Consolidating Statements of Operations and			Guarantor			Non-Guarantor				Molycorp, Inc.
	Comprehensive Loss	Parent		Subsidiaries			Subsidiaries		Eliminations		consolidated
	Revenues	$	—	$	19,237		$	142,421	$	-12,592	$	149,066
	Costs of sales:
	Costs excluding depreciation and amortization		—		-55,517			-107,519		12,592		-150,444
	Depreciation and amortization		—		-9,336			-7,064		—		-16,400
	Gross (loss) profit		—		-45,616			27,838		—		-17,778
	Operating expenses:
	Selling, general and administrative		-3		-15,554			-8,842		—		-24,399
	Corporate development		—		-69			—		—		-69
	Depreciation, amortization and accretion		—		-1,597			-8,475		—		-10,072
	Research and development		—		-1,037			-4,528		—		-5,565
	Impairment of goodwill and other long-lived assets		—		—			-1,118		—		-1,118
	Operating (loss) income		-3		-63,873			4,875		—		-59,001
	Other (expense) income:
	Other income (expense)		4		64			-725		—		-657
	Foreign exchange gains (losses), net		1,727		-1			-1,960		—		-234
	Interest expense, net		-14,093		-744			-1,452		—		-16,289
	Interest income (expense) from intercompany notes		9,211		1,412			-10,623		—		—
	Equity loss from consolidated subsidiaries		-54,858		-333			—		55,191		—
			-58,009		398			-14,760		55,191		-17,180
	Loss before income taxes and equity earnings		-58,012		-63,475			-9,885		55,191		-76,181
	Income tax benefit (expense)		-11,914		14,879			9,937		—		12,902
	Equity in results of affiliates		—		-1,617			-717		—		-2,334
	Loss from continuing operations		-69,926		-50,213			-665		55,191		-65,613
	Loss from discontinued operations, net of tax		—		—			-4,186		—		-4,186
	Net loss		-69,926		-50,213			-4,851		55,191		-69,799
	Net income attributable to noncontrolling interest		—		—			-130		—		-130
	Net loss attributable to Molycorp stockholders	$	-69,926	$	-50,213		$	-4,981	$	55,191	$	-69,929
	Net loss	$	-69,926	$	-50,213		$	-4,851	$	55,191	$	-69,799
	Other comprehensive loss:
	Foreign currency translation adjustments		—		—			4,217		—		4,217
	Comprehensive loss	$	-69,926	$	-50,213		$	-634	$	55,191	$	-65,582
	Comprehensive loss attributable to:
	Molycorp stockholders		-69,926		-50,213			-504		55,191		-65,452
	Noncontrolling interest		—		—			-130		—		-130
		$	-69,926	$	-50,213		$	-634	$	55,191	$	-65,582
		Nine months ended September 30, 2013
		(In thousands)
	Condensed Consolidating Statements of Operations and			Guarantor			Non-Guarantor				Molycorp, Inc.
	Comprehensive Loss	Parent		Subsidiaries			Subsidiaries		Eliminations		consolidated
	Revenues	$	—	$	68,014		$	397,548	$	-34,982	$	430,580
	Costs of sales:
	Costs excluding depreciation and amortization		—		-147,209			-309,472		34,982		-421,699
	Depreciation and amortization		—		-28,523			-20,760		—		-49,283
	Gross (loss) profit		—		-107,718			67,316		—		-40,402
	Operating expenses:
	Selling, general and administrative		-3		-48,870			-27,573		—		-76,446
	Corporate development		—		-256			—		—		-256
	Depreciation, amortization and accretion		—		-3,258			-23,015		—		-26,273
	Research and development		—		-4,428			-14,048		—		-18,476
	Impairment of goodwill and other long-lived assets		—		—			-1,495		—		-1,495
	Operating (loss) income		-3		-164,530			1,185		—		-163,348
	Other (expense) income:
	Other income		4		298			1,128		—		1,430
	Foreign exchange gains (losses), net		1,727		8			-691		—		1,044
	Interest (expense) income, net		-39,978		-5,039			2,210		—		-42,807
	Interest income (expense) from intercompany notes		27,455		4,293			-31,748		—		—
	Equity loss from consolidated subsidiaries		-163,247		-6,742			—		169,989		—
			-174,039		-7,182			-29,101		169,989		-40,333
	Loss before income taxes and equity earnings		-174,042		-171,712			-27,916		169,989		-203,681
Income tax benefit (expense)		-6,030		23,130			21,822		—		38,922
Equity in results of affiliates		—		-5,239			-3,451		—		-8,690
Loss from continuing operations		-180,072		-153,821			-9,545		169,989		-173,449
Loss from discontinued operations, net of tax		—		—			-5,190		—		-5,190
Net loss		-180,072		-153,821			-14,735		169,989		-178,639
Net income attributable to noncontrolling interest		—		—			-1,433		—		-1,433
Net loss attributable to Molycorp stockholders	$	-180,072	$	-153,821		$	-16,168	$	169,989	$	-180,072
Net loss	$	-180,072	$	-153,821		$	-14,735	$	169,989	$	-178,639
Other comprehensive loss:
Foreign currency translation adjustments		—		—			1,585		—		1,585
Comprehensive loss	$	-180,072	$	-153,821		$	-13,150	$	169,989	$	-177,054
Comprehensive loss attributable to:
Molycorp stockholders		-180,072		-153,821			-11,717		169,989		-175,621
Noncontrolling interest		—		—			-1,433		—		-1,433
	$	-180,072	$	-153,821		$	-13,150	$	169,989	$	-177,054
	Three months ended September 30, 2012
	(In thousands)
Condensed Consolidating Statements of Operations and			Guarantor			Non-Guarantor				Molycorp, Inc.
Comprehensive Loss	Parent		Subsidiaries			Subsidiaries		Eliminations		consolidated
Revenues	$	—	$	26,103		$	191,661	$	-12,559	$	205,205
Costs of sales:
Costs excluding depreciation and amortization		—		-38,919			-156,867		12,559		-183,227
Depreciation and amortization		—		-3,375			-7,237		—		-10,612
Gross (loss) profit		—		-16,191			27,557		—		11,366
Operating expenses:
Selling, general and administrative		-29		-20,147			-11,173		—		-31,349
Corporate development		—		-1,073			—		—		-1,073
Depreciation, amortization and accretion		—		-742			-8,842		—		-9,584
Research and development		—		-2,497			-6,432		—		-8,929
Operating (loss) income		-29		-40,650			1,110		—		-39,569
Other (expense) income:
Other (expense) income		—		-68			11		—		-57
Foreign exchange (losses) gains, net		—		-3			1,913		—		1,910
Interest expense, net		-2,920		-1,076			-1,273		—		-5,269
Interest income (expense) from intercompany notes		453		-324			-129		—		—
Equity (loss) earnings from consolidated subsidiaries		-16,395		4,090			—		12,305		—
		-18,862		2,619			522		12,305		-3,416
(Loss) income before income taxes and equity earnings		-18,891		-38,031			1,632		12,305		-42,985
Income tax benefit		—		23,537			5,419		—		28,956
Equity in results of affiliates		—		-682			20		—		-662
(Loss) income from continuing operations		-18,891		-15,176			7,071		12,305		-14,691
Loss from discontinued operations, net of tax		—		—			-760		—		-760
Net (loss) income		-18,891		-15,176			6,311		12,305		-15,451
Net income attributable to noncontrolling interest		—		—			-3,440		—		-3,440
Net (loss) income attributable to Molycorp stockholders	$	-18,891	$	-15,176		$	2,871	$	12,305	$	-18,891
Net (loss) income	$	-18,891	$	-15,176		$	6,311	$	12,305	$	-15,451
Other comprehensive (loss) income:
Foreign currency translation adjustments		—		—			526		—		526
Comprehensive (loss) income	$	-18,891	$	-15,176		$	6,837	$	12,305	$	-14,925
Comprehensive (loss) income attributable to:
Molycorp stockholders		-18,891		-15,176			10,277		12,305		-11,485
Noncontrolling interest		—		—			-3,440		—		-3,440
	$	-18,891	$	-15,176		$	6,837	$	12,305	$	-14,925
	Nine months ended September 30, 2012
	(In thousands)
Condensed Consolidating Statements of Operations and			Guarantor			Non-Guarantor				Molycorp, Inc.
Comprehensive Loss	Parent		Subsidiaries			Subsidiaries		Eliminations		consolidated
	(Revised)
Revenues	$	—	$	121,172		$	293,228	$	-20,315	$	394,085
Costs of sales:
Costs excluding depreciation and amortization		—		-105,185			-251,784		20,315		-336,654
Depreciation and amortization		—		-7,539			-11,526		—		-19,065
Gross profit		—		8,448			29,918		—		38,366
Operating expenses:
Selling, general and administrative		45		-62,746			-15,882		—		-78,583
Corporate development		-46		-19,333			—		—		-19,379
Depreciation, amortization and accretion		—		-1,441			-10,747		—		-12,188
Research and development		—		-10,584			-8,044		—		-18,628
Operating loss		-1		-85,656			-4,755		—		-90,412
Other (expense) income:
Other (expense) income		-37,589		27			-53		—		-37,615
Foreign exchange (losses) gains, net		—		-5			729		—		724
Interest expense, net		-12,602		-194			-2,193		—		-14,989
Interest income (expense) from intercompany notes		1,326		-967			-359		—		—
Equity loss from consolidated subsidiaries		-55,770		-18,302			—		74,072		—
		-104,635		-19,441			-1,876		74,072		-51,880
Loss before income taxes and equity earnings		-104,636		-105,097			-6,631		74,072		-142,292
Income tax benefit		14,660		37,302			6,480		—		58,442
Equity in results of affiliates		—		-1,475			329		—		-1,146
(Loss) income from continuing operations		-89,976		-69,270			178		74,072		-84,996
Loss from discontinued operations, net of tax		—		—			-860		—		-860
Net loss		-89,976		-69,270			-682		74,072		-85,856
Net income attributable to noncontrolling interest		—		—			-4,120		—		-4,120
Net loss attributable to Molycorp stockholders	$	-89,976	$	-69,270		$	-4,802	$	74,072	$	-89,976
Net loss	$	-89,976	$	-69,270		$	-682	$	74,072	$	-85,856
Other comprehensive loss:
Foreign currency translation adjustments		—		—			-1,165		—		-1,165
Comprehensive loss	$	-89,976	$	-69,270		$	-1,847	$	74,072	$	-87,021
Comprehensive (loss) income attributable to:
Molycorp stockholders		-89,976		-69,270			2,273		74,072		-82,901
Noncontrolling interest		—		—			-4,120		—		-4,120
	$	-89,976	$	-69,270		$	-1,847	$	74,072	$	-87,021
Schedule Of Condensed Cash Flow Statement	'
		Nine months ended September 30, 2013
		(In thousands)
				Guarantor			Non-Guarantor				Molycorp, Inc.
	Condensed Consolidating Statements of Cash Flows	Parent		Subsidiaries			Subsidiaries		Eliminations		consolidated
	Net cash (used in) provided by operating activities	$	-2,990	$	-79,888		$	-7,135	$	—	$	-90,013
	Cash flows from investing activities:
	Loans to guarantor		—		—			-40,000		40,000		—
	Loans to parent		—		—			-12,800		12,800		—
	Intercompany advances made		-438,374		—			—		438,374		—
	Loans to non-guarantor		—		-1,300			—		1,300		—
	Repayments of notes receivable from non-guarantor		38,000		264			—		-38,264		—
	Investment in joint ventures		—		-3,423			—		—		-3,423
	Capital expenditures		—		-320,829			-13,768		—		-334,597
	Other investing activities		—		—			-364		—		-364
	Net cash used in investing activities		-400,374		-325,288			-66,932		454,210		-338,384
	Cash flows from financing activities:
	Repayments of debt		—		—			-25,990		—		-25,990
	Net proceeds from sale of common stock		248,150		—			—		—		248,150
	Issuance of 5.50% Convertible Notes		165,600		—			—		—		165,600
	Payments of preferred dividends		-8,539		—			—		—		-8,539
	Dividend paid to noncontrolling interests		—		—			-4,472		—		-4,472
	Borrowings from non-guarantor		12,800		40,000			—		-52,800		—
	Borrowing from guarantor		—		—			1,300		-1,300		—
	Repayments to parent		—		—			-38,000		38,000		—
	Repayments to guarantor		—		—			-264		264		—
	Intercompany advances owed		—		356,867			81,507		-438,374		—
	Other financing activities		—		-797			—		—		-797
	Net cash provided by (used in) financing activities		418,011		396,070			14,081		-454,210		373,952
	Effect of exchange rate changes on cash		—		—			569		—		569
	Net change in cash and cash equivalents		14,647		-9,106			-59,417		—		-53,876
	Cash and cash equivalents at beginning of the period		16,560		18,020			193,210		—		227,790
	Cash and cash equivalents at end of period	$	31,207	$	8,914		$	133,793	$	—	$	173,914
		Nine months ended September 30, 2012
		(In thousands)
				Guarantor			Non-Guarantor				Molycorp, Inc.
		Parent		Subsidiaries			Subsidiaries		Eliminations		consolidated
	Condensed Consolidating Statements of Cash Flows	(Revised)
	Net cash (used in) provided by operating activities	$	-20,495	$	-57,987		$	31,294	$	—	$	-47,188
	Cash flows from investing activities:
	Loans to subsidiaries		-683,063		—			—		683,063		—
	Loans to parent		—		-37,589					37,589		—
	Intercompany advances made		-792,709		—			—		792,709		—
	Repayments from subsidiaries		34,327		—			—		-34,327		—
	Investment in subsidiaries		-350,000		—			—		350,000		—
	Notes receivable to non-guarantor		—		-227,512			—		227,512		—
	Repayments of notes receivable from non-guarantor		—		100,000			—		-100,000		—
	Cash paid in connection with acquisitions, net of cash acquired		—		—			-591,011		—		-591,011
	Investment in joint ventures		—		-28,130			—		—		-28,130
	Deposits		—		-516			—		—		-516
	Capital expenditures		—		-628,407			-16,276		—		-644,683
	Other investing activities		—		—			4,953		—		4,953
	Net cash used in investing activities		-1,791,445		-822,154			-602,334		1,956,546		-1,259,387
	Cash flows from financing activities:
	Capital contributions from stockholder		390,225		—			—		—		390,225
	Contribution from parent		—		—			350,000		-350,000		—
	Proceeds from debt		—		—			9,456		—		9,456
	Repayments of debt		—		-870			-227,561		—		-228,431
	Net proceeds from sale of common stock		132,471		—			—		—		132,471
	Net proceeds from sale of Senior Notes		635,373		—			—		—		635,373
	Issuance of 6.00% Convertible Notes		395,712		—			—		—		395,712
	Payments of preferred dividends		-8,539		—			—		—		-8,539
	Borrowing from parent		—		227,512			455,551		-683,063		—
	Borrowing from guarantor		37,589		—			227,512		-265,101		—
Repayments to parent		—		-34,327			—		34,327		—
Intercompany advances owed		—		680,966			111,743		-792,709		—
Repayments of borrowing to guarantor		—		—			-100,000		100,000		—
Other financing activities		-2,937		-68			-326		—		-3,331
Net cash provided by financing activities		1,579,894		873,213			826,375		-1,956,546		1,322,936
Effect of exchange rate changes on cash		—		—			809		—		809
Net change in cash and cash equivalents		-232,046		-6,928			256,144		—		17,170
Cash and cash equivalents at beginning of the period		407,446		10,758			651		—		418,855
Cash and cash equivalents at end of period	$	175,400	$	3,830		$	256,795	$	—	$	436,025
Schedule Of Error Corrections And Prior Period Adjustments	'
		Nine months ended September 30, 2012
		As reported		Adjustment		Revised
	Guarantor Subsidiaries	(In thousands of dollars)
	Intercompany advances made		680,966	-680,966		—
	Loans to parent		—	-37,589		-37,589
	Net cash used in investing activities		-103,599	-718,555		-822,154
	Intercompany advances owed		—	680,966		680,966
	Net cash provided by financing activities		192,247	680,966		873,213
	Non-Guarantor Subsidiaries
	Intercompany advances made		111,743	-111,743		—
	Net cash used in investing activities		-490,591	-111,743		-602,334
	Intercompany advances owed		—	111,743		111,743
	Net cash provided by financing activities		714,632	111,743		826,375
		Nine months ended September 30, 2012
		As reported		Adjustment		Revised
	Parent	(In thousands of dollars)
	Other expense		—	-37,589		-37,589
	Equity loss from consolidated subsidiaries		-78,699	22,929		-55,770
	Loss before income taxes and equity earnings		-89,976	-14,660		-104,636
	Income tax benefit		—	14,660		14,660
	Net cash provided by (used in) operating activities		17,094	-37,589		-20,495
	Borrowing from guarantor		—	37,589		37,589
	Net cash provided by financing activities		1,542,305	37,589		1,579,894
	Guarantor Subsidiaries
	Other (expense) income		-37,562	37,589		27
	Loss before income taxes and equity earnings		-142,686	37,589		-105,097
	Income tax benefit		51,962	-14,660		37,302
	Loss from continuing operations		-92,199	22,929		-69,270
	Net cash (used in) provided by operating activities		-95,576	37,589		-57,987
	Loans to parent		—	-37,589		-37,589
	Intercompany advances made		680,966	-680,966		—
	Net cash used in investing activities		-103,599	-718,555		-822,154

Discontinued_Operations_Tables

Discontinued Operations (Tables)	9 Months Ended
	Sep. 30, 2013
Discontinued Operations [Abstract]	'
Schedule Of Disposal Group Carrying Amounts And Operating Results Included In Discontinued Operations	'
	As of September 30, 2013, the disposal group had the following carrying amounts, which are recorded under “Prepaid expenses and other current assets” in the condensed consolidated balance sheet:
		September 30,
		2013
		(In thousands)
	Land	$	50
	Buildings		700
	Equipment		750
	Inventory		819
	Carrying value of disposal group	$	2,319
	The following table summarizes the operating results of the Napanee facility included in discontinued operations for the three and nine months ended September 30, 2013 and 2012:
		Three Months Ended September 30,				Nine Months Ended September 30,
		2013		2012		2013		2012
			(In thousands)
	Revenues	$	216	$	399	$	1,931	$	566
	Costs of sales		-913		-901		-3,044		-1,115
	Selling, general and administrative expenses		-34		-119		-307		-138
	Depreciation		—		-139		-315		-173
	Operating loss		-731		-760		-1,735		-860
	Loss on assets impairment		-3,455		—		-3,455		—
	Income tax		—		—		—		—
	Net loss	$	-4,186	$	-760	$	-5,190	$	-860

Basis_Of_Presentation_Details

Basis Of Presentation (Details)	Sep. 30, 2013
	country
	employee
	item
Basis Of Presentation [Abstract]	'
Number of continents in which entity operates	3
Number of employees	2,650
Number of worldwide locations	27
Number of countries in which entity operates	11

Liquidity_And_Capital_Requirem1

Liquidity And Capital Requirements (Details) (USD $)	9 Months Ended					9 Months Ended	38 Months Ended	0 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Oct. 21, 2013	Oct. 15, 2013	Sep. 30, 2013	Sep. 30, 2013
					Jiangyin Jia Hua Advanced Material Resources Co Ltd [Member]	Molycorp Mountain Pass Facility [Member]	Molycorp Mountain Pass Facility [Member]	Subsequent Event [Member]	Subsequent Event [Member]	Minimum [Member]	Maximum [Member]
						t				All Operating Segments [Member]	All Operating Segments [Member]
Capital Expenditures [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Total current estimated costs	'	'	'	'	'	$1,550,000,000	$1,550,000,000	'	'	'	'
Annual design capacity	'	'	'	'	'	19,050	'	'	'	'	'
Capital expenditures	334,597,000	644,683,000	'	'	'	'	1,370,000,000	'	'	'	'
Available cash balances	173,914,000	436,025,000	227,790,000	418,855,000	'	'	'	'	'	'	'
Estimated future capital expenditures remainder of 2013	'	'	'	'	'	60,000,000	60,000,000	'	'	'	'
Estimated expenditures on other maintenance and expansion capital expenditures in 2013	'	'	'	'	'	'	'	'	'	5,000,000	8,000,000
Estimated capital expenditures in 2014	'	'	'	'	'	40,000,000	40,000,000	'	'	'	'
Estimated capital expenditures in 2015	'	'	'	'	'	80,000	80,000	'	'	'	'
Approximate final payment to noncontrolling shareholder	'	'	'	'	6,000,000	'	'	'	'	'	'
Preferred stock dividend payments, if declared in the remainder of the year	2,800,000	'	'	'	'	'	'	'	'	'	'
Cash and cash equivalents	173,914,000	436,025,000	227,790,000	418,855,000	'	'	'	'	'	'	'
Net proceeds from sale of common stock	$248,150,000	$132,471,000	'	'	'	'	'	$247,500,000	$247,500,000	'	'

Segment_Information_Details

Segment Information (Details) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012		Dec. 31, 2012
					segment
Segment Information	'		'		'		'		'
Number of segments	'		'		4		'		'
Sales:	'		'		'		'		'
Revenues:	$149,066,000		$205,205,000		$430,580,000		$394,085,000		'
Total revenues	149,066,000		205,205,000		430,580,000		394,085,000		'
Depreciation, depletion and accretion	-26,472,000		-20,196,000		-75,556,000		-31,253,000		'
Operating (loss) income	-59,001,000		-39,569,000		-163,348,000		-90,412,000		'
(Loss) income before income taxes and equity earnings	-76,181,000		-42,985,000		-203,681,000		-142,292,000		'
Total assets at period end	3,027,276,000		'		3,027,276,000		'		2,992,535,000
Capital expenditures	62,690,000	[1]	195,864,000	[1]	220,090,000	[1]	692,751,000	[1]	'
Resources [Member]	'		'		'		'		'
Sales:	'		'		'		'		'
Revenues:	4,655,000		17,150,000		30,235,000		78,162,000		'
Depreciation, depletion and accretion	-10,853,000		-4,035,000		-31,536,000		-8,743,000		'
Operating (loss) income	-55,526,000		-23,966,000		-136,055,000		-23,594,000		'
(Loss) income before income taxes and equity earnings	-56,139,000		-25,506,000		-135,047,000		-25,044,000		'
Total assets at period end	1,880,127,000		'		1,880,127,000		'		'
Capital expenditures	57,637,000	[1]	187,611,000	[1]	205,669,000	[1]	675,836,000	[1]	'
Chemicals And Oxides [Member]	'		'		'		'		'
Sales:	'		'		'		'		'
Revenues:	50,791,000		87,820,000		135,180,000		134,158,000		'
Depreciation, depletion and accretion	-5,960,000		-5,685,000		-17,087,000		-7,419,000		'
Operating (loss) income	-1,399,000		2,149,000		-19,879,000		-21,863,000		'
(Loss) income before income taxes and equity earnings	-1,527,000		1,201,000		-18,438,000		-23,663,000		'
Total assets at period end	567,207,000		'		567,207,000		'		'
Capital expenditures	1,573,000	[1]	2,597,000	[1]	5,672,000	[1]	6,615,000	[1]	'
Magnetic Materials And Alloys [Member]	'		'		'		'		'
Sales:	'		'		'		'		'
Revenues:	72,626,000		74,789,000		193,417,000		125,277,000		'
Depreciation, depletion and accretion	-7,458,000		-8,857,000		-20,360,000		-10,810,000		'
Operating (loss) income	11,062,000		1,419,000		28,463,000		-1,544,000		'
(Loss) income before income taxes and equity earnings	39,291,000		1,215,000		67,089,000		-2,381,000		'
Total assets at period end	621,127,000		'		621,127,000		'		'
Capital expenditures	1,457,000	[1]	1,432,000	[1]	2,910,000	[1]	1,612,000	[1]	'
Rare Metals [Member]	'		'		'		'		'
Sales:	'		'		'		'		'
Revenues:	20,994,000		25,446,000		71,748,000		56,488,000		'
Depreciation, depletion and accretion	-2,144,000		-1,576,000		-6,402,000		-4,185,000		'
Operating (loss) income	-3,055,000		-3,014,000		-2,455,000		-1,087,000		'
(Loss) income before income taxes and equity earnings	-4,807,000		-3,052,000		57,000		-2,138,000		'
Total assets at period end	100,794,000		'		100,794,000		'		'
Capital expenditures	1,946,000	[1]	2,837,000	[1]	5,595,000	[1]	6,955,000	[1]	'
Selling, General And Administrative Expenses [Member]	'		'		'		'		'
Sales:	'		'		'		'		'
Restructuring charges	'		'		2,100,000		'		'
Operating Segments [Member]	'		'		'		'		'
Sales:	'		'		'		'		'
Total revenues	149,066,000		205,205,000		430,580,000		394,085,000		'
Operating Segments [Member] | Resources [Member]	'		'		'		'		'
Sales:	'		'		'		'		'
Total revenues	13,513,000		20,895,000		48,403,000		84,139,000		'
Operating Segments [Member] | Chemicals And Oxides [Member]	'		'		'		'		'
Sales:	'		'		'		'		'
Total revenues	57,965,000		99,379,000		163,656,000		149,654,000		'
Operating Segments [Member] | Magnetic Materials And Alloys [Member]	'		'		'		'		'
Sales:	'		'		'		'		'
Total revenues	72,626,000		74,789,000		193,417,000		125,277,000		'
Operating Segments [Member] | Rare Metals [Member]	'		'		'		'		'
Sales:	'		'		'		'		'
Total revenues	20,994,000		25,446,000		71,748,000		56,488,000		'
Corporate, Non-Segment [Member] | Corporate And Other [Member]	'		'		'		'		'
Sales:	'		'		'		'		'
Depreciation, depletion and accretion	-57,000		-43,000		-171,000		-96,000		'
Operating (loss) income	-10,806,000		-16,526,000		-32,321,000		-66,804,000		'
(Loss) income before income taxes and equity earnings	-53,722,000		-17,212,000		-116,241,000		-113,546,000		'
Total assets at period end	1,329,485,000		'		1,329,485,000		'		'
Capital expenditures	77,000	[1]	1,387,000	[1]	244,000	[1]	1,733,000	[1]	'
Intersegment Elimination [Member]	'		'		'		'		'
Sales:	'		'		'		'		'
Revenues:	-16,032,000		-15,304,000		-46,644,000		-21,473,000		'
Total revenues	-16,032,000		-15,304,000		-46,644,000		-21,473,000		'
Operating (loss) income	723,000		369,000		-1,101,000		24,480,000		'
(Loss) income before income taxes and equity earnings	723,000		369,000		-1,101,000		24,480,000		'
Total assets at period end	-1,471,464,000		'		-1,471,464,000		'		'
Intercompany costs	16,755,000		15,673,000		45,543,000		45,952,000		'
Intersegment Elimination [Member] | Resources [Member]	'		'		'		'		'
Sales:	'		'		'		'		'
Revenues:	8,858,000		3,745,000		18,168,000		5,977,000		'
Intersegment Elimination [Member] | Chemicals And Oxides [Member]	'		'		'		'		'
Sales:	'		'		'		'		'
Revenues:	$7,174,000		$11,559,000		$28,476,000		$15,496,000		'
[1]	On an accrual basis excluding capitalized interest.

Trade_Accounts_Receivable_Deta

Trade Accounts Receivable (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Trade Accounts Receivable [Abstract]	'	'
Allowance for doubtful accounts	$2.60	$2.60

Inventory_Narrative_Details

Inventory (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Inventory [Abstract]	'	'	'	'
Production costs expensed that would have been allocated to additional tons produced, assuming operations at normal production rates	$18.20	$3.90	$65.70	$9.80
Finished goods and work-in-process inventory	19.6	15	60.7	41.1
Write-down of stockpile inventory	$6.90	$0	$13.70	$0

Inventory_Schedule_Of_Inventor

Inventory (Schedule Of Inventory) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Current:	'	'
Concentrate stockpiles	$660	$6,393
Raw materials	58,269	95,248
Work in process	41,797	55,229
Finished goods	61,601	114,903
Materials and supplies	21,114	15,603
Total current	183,441	287,376
Long-term:	'	'
Concentrate stockpiles	4	4
Raw materials	24,321	26,092
Total long-term	$24,325	$26,096

Deposits_Details

Deposits (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Deposits [Line Items]	'	'
Deposits	$25,997,000	$26,769,000
Deposits related to construction insurance program	2,500,000	'
Other restricted cash requirements related to deposits	3,000,000	'
Kern River Gas Transmission Company [Member]	'	'
Deposits [Line Items]	'	'
Escrow deposit	$20,500,000	'

Property_Plant_And_Equipment_N2

Property, Plant And Equipment, Net (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Property, Plant And Equipment, Net [Abstract]	'	'	'	'
Plant modernization and other capital costs	$83	$218.10	$281.30	$728.20
Capitalized interest related to plant modernization and other capitalized costs	$20.30	$22.20	$61.20	$35.50

Property_Plant_And_Equipment_N3

Property, Plant And Equipment, Net (Schedule Of Property, Plant And Equipment) (Details) (USD $)	Sep. 30, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified
Property, Plant and Equipment [Line Items]	'		'
Property, plant and equipment at cost	$1,865,043		$1,589,235
Less accumulated depreciation	-85,959		-44,931
Property, plant and equipment, net	1,779,084		1,544,304
Land [Member]	'		'
Property, Plant and Equipment [Line Items]	'		'
Property, plant and equipment at cost	12,678		12,475
Land Improvements [Member]	'		'
Property, Plant and Equipment [Line Items]	'		'
Property, plant and equipment at cost	68,903		63,269
Buildings And Improvements [Member]	'		'
Property, Plant and Equipment [Line Items]	'		'
Property, plant and equipment at cost	404,436		237,379
Plant And Equipment [Member]	'		'
Property, Plant and Equipment [Line Items]	'		'
Property, plant and equipment at cost	290,678		194,934
Vehicles [Member]	'		'
Property, Plant and Equipment [Line Items]	'		'
Property, plant and equipment at cost	2,942		2,842
Computer Software [Member]	'		'
Property, Plant and Equipment [Line Items]	'		'
Property, plant and equipment at cost	12,254		9,528
Furnitures And Fixtures [Member]	'		'
Property, Plant and Equipment [Line Items]	'		'
Property, plant and equipment at cost	1,044		1,116
Construction In Progress [Member]	'		'
Property, Plant and Equipment [Line Items]	'		'
Property, plant and equipment at cost	1,010,173	[1]	1,011,541	[1]
Natural Gas Delivery Facility Under Capital Lease [Member]	'		'
Property, Plant and Equipment [Line Items]	'		'
Capital leased assets	15,658		15,658
Mining Equipment Under Capital Lease [Member]	'		'
Property, Plant and Equipment [Line Items]	'		'
Capital leased assets	5,992		'
Mineral Properties [Member]	'		'
Property, Plant and Equipment [Line Items]	'		'
Property, plant and equipment at cost	24,115		24,327
Exploration Rights [Member]	'		'
Property, Plant and Equipment [Line Items]	'		'
Property, plant and equipment at cost	$16,170		$16,166
[1]	Represents costs incurred at the Molycorp Mountain Pass facility and all other capital projects. See Note 2.

Mineral_Properties_Development1

Mineral Properties, Development Costs And Exploration Rights (Details) (USD $)	Sep. 30, 2013
In Millions, unless otherwise specified
Mineral Properties, Development Costs And Exploration Rights [Abstract]	'
Capitalized depletion costs	$0.20

Goodwill_And_Other_Intangible_2

Goodwill And Other Intangible Assets (Narrative) (Details) (USD $)	3 Months Ended	9 Months Ended
	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012
Finite-Lived And Indefinite-Lived Intangible Assets [Line Items]	'	'	'
Additional goodwill impairment	$31,616,000	'	'
Amortization of intangible assets	'	32,395,000	2,700,000
Trade Names [Member]	'	'	'
Finite-Lived And Indefinite-Lived Intangible Assets [Line Items]	'	'	'
Indefinite-lived intangible assets	'	$14,800,000	'

Goodwill_And_Other_Intangible_3

Goodwill And Other Intangible Assets (Schedule Of Goodwill) (Details) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2012	Sep. 30, 2013
Goodwill [Line Items]	'	'	'
Goodwill	$239,742	$239,742	$239,742
Adjustment	'	31,616	'
Additional impairment	-31,616	'	'
Chemicals And Oxides [Member]	'	'	'
Goodwill [Line Items]	'	'	'
Goodwill	125,229	125,229	125,229
Adjustment	'	16,132	'
Additional impairment	-16,132	'	'
Magnetic Materials And Alloys [Member]	'	'	'
Goodwill [Line Items]	'	'	'
Goodwill	102,808	102,808	102,808
Adjustment	'	16,716	'
Additional impairment	-16,716	'	'
Rare Metals [Member]	'	'	'
Goodwill [Line Items]	'	'	'
Goodwill	11,705	11,705	11,705
Adjustment	'	-1,232	'
Additional impairment	$1,232	'	'

Goodwill_And_Other_Intangible_4

Goodwill And Other Intangible Assets (Schedule Of Amortizable Intangible Assets) (Details) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Finite-Lived And Indefinite-Lived Intangible Assets [Line Items]	'	'	'
At period start	$479,900	'	'
Additions	48	'	'
Foreign currency translation adjustment	-262	'	'
At period end	479,686	'	'
At period start	28,962	'	'
Adjustments	-1,142	'	'
Amortization	32,395	2,700	'
At period end	60,215	'	'
Net book value	419,471	'	450,938
Customer Relationships [Member]	'	'	'
Finite-Lived And Indefinite-Lived Intangible Assets [Line Items]	'	'	'
At period start	344,774	'	'
Additions	48	'	'
Foreign currency translation adjustment	-262	'	'
At period end	344,560	'	'
At period start	14,095	'	'
Adjustments	-269	'	'
Amortization	16,395	'	'
At period end	30,221	'	'
Net book value	314,339	'	'
Rare Earth Quotas [Member]	'	'	'
Finite-Lived And Indefinite-Lived Intangible Assets [Line Items]	'	'	'
At period start	78,300	'	'
Additions	'	'	'
Foreign currency translation adjustment	'	'	'
At period end	78,300	'	'
At period start	4,035	'	'
Adjustments	'	'	'
Amortization	5,238	'	'
At period end	9,273	'	'
Net book value	69,027	'	'
Patents [Member]	'	'	'
Finite-Lived And Indefinite-Lived Intangible Assets [Line Items]	'	'	'
At period start	33,252	'	'
Additions	'	'	'
Foreign currency translation adjustment	'	'	'
At period end	33,252	'	'
At period start	9,365	'	'
Adjustments	'	'	'
Amortization	10,131	'	'
At period end	19,496	'	'
Net book value	13,756	'	'
Land Use Rights [Member]	'	'	'
Finite-Lived And Indefinite-Lived Intangible Assets [Line Items]	'	'	'
At period start	3,568	'	'
Additions	'	'	'
Foreign currency translation adjustment	'	'	'
At period end	3,568	'	'
At period start	66	'	'
Adjustments	'	'	'
Amortization	121	'	'
At period end	187	'	'
Net book value	3,381	'	'
Other [Member]	'	'	'
Finite-Lived And Indefinite-Lived Intangible Assets [Line Items]	'	'	'
At period start	4,420	'	'
Additions	'	'	'
Foreign currency translation adjustment	'	'	'
At period end	4,420	'	'
At period start	249	'	'
Adjustments	'	'	'
Amortization	461	'	'
At period end	710	'	'
Net book value	3,710	'	'
Trade Names [Member]	'	'	'
Finite-Lived And Indefinite-Lived Intangible Assets [Line Items]	'	'	'
At period start	15,586	'	'
Additions	'	'	'
Foreign currency translation adjustment	'	'	'
At period end	15,586	'	'
At period start	1,152	'	'
Adjustments	-873	'	'
Amortization	49	'	'
At period end	328	'	'
Net book value	$15,258	'	'

Investments_Details

Investments (Details) (USD $)

0 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

15 Months Ended

3 Months Ended

9 Months Ended

9 Months Ended

Sep. 13, 2011

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Jun. 11, 2012

Jun. 11, 2012

Sep. 30, 2013

Mar. 31, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Mar. 31, 2013

Jan. 31, 2012

Jan. 31, 2012

Jan. 31, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Jun. 11, 2012

Jun. 11, 2012

Sep. 30, 2013

Jun. 11, 2012

Atlantic Metals [Member]

Vive Crop Protection [Member]

Intermetallics Japan [Member]

Intermetallics Japan [Member]

Intermetallics Japan [Member]

Intermetallics Japan [Member]

Intermetallics Japan [Member]

Intermetallics Japan [Member]

Intermetallics Japan [Member]

Intermetallics Japan [Member]

Intermetallics Japan [Member]

Keli [Member]

Keli [Member]

Keli [Member]

Keli [Member]

TMT [Member]

Ingal Stade [Member]

Ingal Stade [Member]

Molycorp [Member]

Daido Steel Co. Ltd [Member]

Mitsubishi Corporation [Member]

Schedule Of Equity Method Investments [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Investment in Boulder Wind Power's Series B convertible preferred stock

$20,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Capital contribution ratio (as a percent)

'

'

'

'

'

'

'

'

'

'

'

'

'

30.00%

35.50%

34.50%

'

'

'

'

'

'

'

Capital contribution

'

'

'

3,423,000

28,130,000

'

'

'

3,400,000

'

'

'

31,100,000

'

'

'

'

'

'

'

'

'

'

Loss from the entity's proportional ownership in joint venture

'

2,334,000

662,000

8,690,000

1,146,000

'

'

1,600,000

'

200,000

5,200,000

800,000

'

'

'

'

700,000

300,000

3,100,000

'

'

300,000

'

Ownership in subsidiary (as a percent)

'

'

'

'

'

19.50%

7.00%

'

'

'

'

'

'

'

'

'

'

'

'

25.00%

33.00%

'

50.00%

Fair value of the equity investment of a business acquisition

'

'

'

'

'

$1,400,000

$900,000

'

'

'

'

'

'

'

'

'

'

'

'

$12,200,000

$1,600,000

'

$4,900,000

Acquisitions_Narrative_Details

Acquisitions (Narrative) (Details)

3 Months Ended

9 Months Ended

3 Months Ended

0 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

0 Months Ended

3 Months Ended

Dec. 31, 2012

Sep. 30, 2013

Mar. 28, 2012

Dec. 31, 2012

Jun. 11, 2012

Dec. 31, 2012

Sep. 30, 2012

Sep. 30, 2012

Jun. 11, 2012

Mar. 28, 2012

Dec. 31, 2012

Jun. 11, 2012

Jun. 11, 2012

Jun. 11, 2012

Jun. 11, 2012

Dec. 31, 2012

USD ($)

CAD

Magnetic Materials And Alloys [Member]

Molycorp Canada [Member]

Molycorp Canada [Member]

Molycorp Canada [Member]

Molycorp Canada [Member]

Molycorp Canada [Member]

Molycorp Canada [Member]

Molycorp Canada [Member]

Molycorp [Member]

MCP Exchangeco Inc. [Member]

MCP Exchangeco Inc. [Member]

Preliminary Allocation Of Consideration Transferred As Of December 31, 2012 [Member]

Final Allocation Of Consideration Transferred [Member]

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

CAD

CAD

Magnetic Materials And Alloys [Member]

Molycorp Canada [Member]

Molycorp Canada [Member]

Molycorp Canada [Member]

Molycorp Canada [Member]

USD ($)

USD ($)

USD ($)

USD ($)

Business Acquisition [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Purchase price

'

'

'

'

$1,192,300,000

'

'

'

'

'

'

'

'

'

$1,192,325,000

$1,192,325,000

Cash consideration paid for Molycorp Canada (in CAD per share)

'

'

'

'

'

'

'

'

11.3

'

'

'

'

'

'

'

Share consideration paid for Molycorp Canada (in shares)

'

'

'

'

'

'

'

'

'

'

'

0.4242

'

0.4242

'

'

Cash consideration

'

'

'

'

'

'

'

'

'

'

'

'

'

'

908,181,000

908,181,000

Notional amount of derivatives

'

'

870,000,000

'

'

'

'

'

'

870,000,000

'

'

'

'

'

'

Common stock issued to acquire the entity (in shares)

'

'

'

'

'

'

'

'

'

'

'

13,545,426

507,203

507,203

'

'

No par value

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fair value of Molycorp common stock issued

'

'

'

'

'

'

'

'

'

'

'

'

'

'

284,144,000

284,144,000

Increase in goodwill impairment loss

'

'

'

'

'

31,600,000

'

'

'

'

'

'

'

'

'

'

Impairment of goodwill

31,616,000

'

'

16,716,000

'

287,900,000

'

'

'

'

'

'

'

'

'

'

Impairment of other long-lived assets

'

'

'

'

'

'

'

'

'

'

6,000,000

'

'

'

'

'

Other actual and pro forma information

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Finite-lived assets, useful life, minimum

'

'2 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Finite-lived assets, useful life, maximum

'

'30 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Direct transaction expenses excluded from nonrecurring expense

'

'

'

'

'

'

'

115,200,000

'

'

'

'

'

'

'

'

Business acquisition, transaction costs

'

'

'

'

'

'

$500,000

$62,000,000

'

'

'

'

'

'

'

'

Acquisitions_Summarizes_The_Pu

Acquisitions (Summarizes The Purchase Prices And Opening Balance Sheets For The Acquisitions) (Details) (Molycorp Canada [Member], USD $)	0 Months Ended		0 Months Ended	3 Months Ended
In Thousands, unless otherwise specified	Jun. 11, 2012	Dec. 31, 2012	Jun. 11, 2012	Dec. 31, 2012
		Measurement Period Adjustments [Member]	Preliminary Allocation Of Consideration Transferred As Of December 31, 2012 [Member]	Final Allocation Of Consideration Transferred [Member]
Purchase consideration:	'	'	'	'
Cash consideration	'	'	$908,181	$908,181
Fair value of Molycorp common stock issued	'	'	284,144	284,144
Total purchase consideration	1,192,300	'	1,192,325	1,192,325
Fair values of the assets and liabilities acquired:	'	'	'	'
Cash and cash equivalents	'	'	317,169	317,169
Restricted cash	'	'	4,951	4,951
Accounts receivable	'	'	101,470	101,470
Inventory	'	'	250,989	250,989
Prepaid expenses and other current assets	'	'	26,893	26,893
Property, plant and equipment	'	'	75,745	75,745
Investments	'	-1,091	21,019	19,928
Intangibles	'	'	482,234	482,234
Deferred tax charges	'	'	13,435	13,435
Deferred tax assets	'	-1,423	11,473	10,050
Goodwill	'	31,616	494,809	526,425
Other non-current assets	'	'	4,367	4,367
Accounts payable and accrued expenses	'	'	-138,576	-138,576
Debt	'	'	-255,338	-255,338
Other current liabilities	'	'	-33,990	-33,990
Deferred tax liabilities	'	5,880	-154,309	-148,429
Other non-current liabilities	'	'	-14,255	-14,255
Non-controlling interests	'	($34,982)	($15,761)	($50,743)

Acquisitions_Summary_Of_Actual

Acquisitions (Summary Of Actual And Pro Forma Information) (Details) (Molycorp Canada [Member], USD $)	9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2012
Molycorp Canada [Member]	'
Unaudited proforma	'
Revenues	$729,469
Net Loss	-74,229
Net Loss Attributable To Molycorp	($82,056)
Loss per share	($0.77)

Accrued_Expenses_Details

Accrued Expenses (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Accrued Expenses	'	'
Defined contribution plan	$1,440	$1,400
Professional fees	133	4,971
Accrued payroll and related benefits	7,254	7,532
Sales and use tax	1,768	7,187
Bonus accrual	3,846	3,503
Interest payable	28,076	15,253
Advance from customer	80	1,753
Withholding taxes	3,433	2,929
Amount payable to noncontrolling shareholder	6,211	9,640
Other accrued expenses	9,204	4,845
Total accrued expenses	$61,445	$59,013

Asset_Retirement_Obligation_Na

Asset Retirement Obligation (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Sep. 30, 2013
Asset Retirement Obligation [Line Items]	'	'
Asset retirement obligation, current	$3,500,000	$6,700,000
Revisions in estimated cash flows	7,872,000	'
Financial assurance requirement satisfied with surety bonds	'	28,800,000
Molycorp Mountain Pass Facility [Member]	'	'
Asset Retirement Obligation [Line Items]	'	'
Revisions in estimated cash flows	3,800,000	'
Demolition And Reclamation Of The Old Mill And Mineral Recovery Areas At The Molycorp Mountain Pass Facility [Member]	'	'
Asset Retirement Obligation [Line Items]	'	'
Revisions in estimated cash flows	$4,100,000	'

Asset_Retirement_Obligation_Sc

Asset Retirement Obligation (Schedule Of Activity In Asset Retirement Obligation) (Details) (USD $)	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Asset retirement obligation activity	'	'
Balance at beginning of period	$22,125	$15,541
Obligations settled	-2,384	-2,954
Accretion expense	1,032	1,299
Revisions in estimated cash flows	'	7,872
Loss on settlement	'	367
Balance at end of period	$20,773	$22,125

Recovered_Sheet1

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

Sep. 30, 2013

Jul. 31, 2013

31-May-13

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Jan. 30, 2013

Sep. 30, 2013

Mar. 01, 2013

Jan. 30, 2013

Sep. 30, 2013

Mining Equipment Under Capital Lease [Member]

Mining Equipment Under Capital Lease [Member]

Mining Equipment Under Capital Lease [Member]

Bank Loans With A Weighted Average Rate Of 4.23% Due September 2013 - September 2017 [Member]

Bank Loans With A Weighted Average Rate Of 3.57% Due January 2013 - September 2017 [Member]

6.00% Convertible Notes, Net Of Discount, Due September 2017 [Member]

5.00% Debentures, Net Of Discount, Due December 2017 [Member]

5.00% Debentures, Net Of Discount, Due December 2017 [Member]

5.50% Convertible Notes, Net Of Discount, Due February 2018 [Member]

5.50% Convertible Notes, Net Of Discount, Due February 2018 [Member]

5.50% Convertible Notes, Net Of Discount, Due February 2018 [Member]

5.50% Convertible Notes, Net Of Discount, Due February 2018 [Member]

10% Senior Secured Notes, Net Of Discount, Due June 2020 [Member]

agreement

Notes Payable To Banks [Member]

Notes Payable To Banks [Member]

Convertible Debt [Member]

Convertible Subordinated Debt [Member]

Convertible Subordinated Debt [Member]

Convertible Debt [Member]

Convertible Debt [Member]

Convertible Debt [Member]

Convertible Debt [Member]

Secured Debt [Member]

Common Stock [Member]

Officers, Directors And Other Related Parties [Member]

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Weighted average interest rate

'

'

'

'

3.66%

3.57%

'

'

'

'

'

'

'

'

Long-term Debt, by Maturity [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Remainder of 2013

$13,800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

2014

1,500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

2015

1,500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

2016

230,800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

2017

416,900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Thereafter

823,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Capital leased assets, number of units

'

'

5

'

'

'

'

'

'

'

'

'

'

'

Long-term purchase commitment, time period

'

'48 months

'48 months

'

'

'

'

'

'

'

'

'

'

'

Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total capital leases payments due

50,400,000

'

'

6,600,000

'

'

'

'

'

'

'

'

'

'

Capital leases, future minimum payments, executory costs and imputed interest

'

'

'

600,000

'

'

'

'

'

'

'

'

'

'

Capital leases, future minimum payments, remainder of fiscal year

1,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Due in 2014

6,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Due in 2015

6,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Due in 2016

6,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Due in 2017

5,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Due thereafter

22,900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Capital leases, future minimum payments, executory costs

1,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Capital leases, future minimum payments, imputed interest

27,900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Repurchased face amount

'

'

'

'

'

'

'

300,000

'

'

'

'

'

'

Debt instrument, repurchase amount

'

'

'

'

'

'

'

200,000

'

'

'

'

'

'

Debt conversion, converted instrument, shares issued

'

'

'

'

'

'

'

'

2,393

'

'

'

'

'

Debt instrument, face amount

'

'

'

'

'

'

'

'

'

150,000,000

'

'

'

'

Interest rate

'

'

'

'

'

'

6.00%

5.00%

'

5.50%

5.50%

'

'

10.00%

Proceeds from related party debt

'

'

'

'

'

'

'

'

'

'

'

'

20,500,000

'

Underwriter option to purchase additional principal, face amount

'

'

'

'

'

'

'

'

'

'

'

22,500,000

'

'

Proceeds from issuance of long-term debt

'

'

'

'

'

'

'

'

'

165,600,000

'

'

'

'

Conversion ratio of principal debt

'

'

'

'

'

'

'

'

'

0.1388889

'

'

'

'

Conversion ratio, price per share (in dollars per share)

'

'

'

'

'

'

'

'

'

$7.20

'

'

'

'

Percentage above which the company has the right to redeem the notes

'

'

'

'

'

'

'

'

'

130.00%

'

'

'

'

Number of trading days

'

'

'

'

'

'

'

'

'

'20 days

'

'

'

'

Number of consecutive trading days

'

'

'

'

'

'

'

'

'

'30 days

'

'

'

'

Fair market value of assets excluded from security interest, maximum

'

'

'

'

'

'

'

'

'

'

'

'

'

$15,000,000

Cash collateral excluded from security interest, maximum

'

'

'

'

'

'

'

'

'

'

'

'

'

105.00%

Voting stock of foreign subsidiaries excluded from security interest, minimum

'

'

'

'

'

'

'

'

'

'

'

'

'

65.00%

Recovered_Sheet2

Debt and Capital Lease Obligations (Schedule Of Long-Term Debt Instruments) (Details) (USD $)

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Jan. 30, 2013

Sep. 30, 2013

Dec. 31, 2012

In Thousands, unless otherwise specified

Bank Loans With A Weighted Average Rate Of 4.23% Due September 2013 - September 2017 [Member]

Bank Loans With A Weighted Average Rate Of 3.57% Due January 2013 - September 2017 [Member]

3.25% Convertible Notes, Net Of Discount, Due June 2016 [Member]

3.25% Convertible Notes, Net Of Discount, Due June 2016 [Member]

6.00% Convertible Notes, Net Of Discount, Due September 2017 [Member]

6.00% Convertible Notes, Net Of Discount, Due September 2017 [Member]

5.00% Debentures, Net Of Discount, Due December 2017 [Member]

5.00% Debentures, Net Of Discount, Due December 2017 [Member]

5.50% Convertible Notes, Net Of Discount, Due February 2018 [Member]

5.50% Convertible Notes, Net Of Discount, Due February 2018 [Member]

10% Senior Secured Notes, Net Of Discount, Due June 2020 [Member]

10% Senior Secured Notes, Net Of Discount, Due June 2020 [Member]

Notes Payable To Banks [Member]

Notes Payable To Banks [Member]

Convertible Debt [Member]

Convertible Debt [Member]

Convertible Debt [Member]

Convertible Debt [Member]

Convertible Subordinated Debt [Member]

Convertible Subordinated Debt [Member]

Convertible Debt [Member]

Convertible Debt [Member]

Secured Debt [Member]

Secured Debt [Member]

Molycorp Canada And Molycorp Silmet [Member]

Molycorp Canada And Molycorp Silmet [Member]

Long-term Debt, Current and Non-Current [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Current portion of debt outstanding

$14,812

$39,252

$14,812

$39,252

'

'

'

'

'

'

'

'

'

'

Non-Current portion of debt outstanding

1,337,406

1,173,669

3,072

4,118

204,903

198,689

342,883

331,977

2,495

2,774

146,961

'

637,092

636,111

Capital lease obligations, Current

1,861

352

'

'

'

'

'

'

'

'

'

'

'

'

Capital lease obligations, Non-Current

18,850

15,163

'

'

'

'

'

'

'

'

'

'

'

'

Total debt and capital lease obligations, Current

16,673

39,604

'

'

'

'

'

'

'

'

'

'

'

'

Total debt and capital lease obligations, Non-Current

$1,356,256

$1,188,832

'

'

'

'

'

'

'

'

'

'

'

'

Interest rate

'

'

'

'

3.25%

'

6.00%

'

5.00%

'

5.50%

5.50%

10.00%

'

Debt_and_Capital_Lease_Obligat2

Debt and Capital Lease Obligations (Schedule Of Long-Term Debt Conversions) (Details) (USD $)	3 Months Ended				9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012		Dec. 31, 2012
Debt Instrument [Line Items]	'		'		'		'		'
Capitalized interest	$20,300		$22,200		$61,200		$35,500		'
Convertible Debt [Member] | 3.25% Convertible Notes, Net Of Discount, Due June 2016 [Member]	'		'		'		'		'
Debt Instrument [Line Items]	'		'		'		'		'
Liability component	201,905	[1]	'		201,905	[1]	'		196,702	[1]
Equity component	36,251		'		36,251		'		36,251
Accretion of liability component	1,772		1,651		5,203		4,849		'
Interest cost	3,988	[2]	3,854	[2]	11,839	[2]	11,446	[2]	'
Capitalized interest	2,373		3,439		7,178		10,598		'
Convertible Debt [Member] | 6.00% Convertible Notes, Net Of Discount, Due September 2017 [Member]	'		'		'		'		'
Debt Instrument [Line Items]	'		'		'		'		'
Liability component	339,304	[1]	'		339,304	[1]	'		330,177	[1]
Equity component	68,695		'		68,695		'		68,695
Accretion of liability component	2,888		1,147		8,491		1,147		'
Interest cost	9,969	[2]	7,740	[2]	29,691	[2]	7,740	[2]	'
Capitalized interest	5,891		3,493		17,959		3,493		'
Convertible Debt [Member] | 5.50% Convertible Notes, Net Of Discount, Due February 2018 [Member]	'		'		'		'		'
Debt Instrument [Line Items]	'		'		'		'		'
Liability component	146,166	[1]	'		146,166	[1]	'		'
Equity component	21,815		'		21,815		'		'
Accretion of liability component	918		'		2,382		'		'
Interest cost	3,609	[2]	'		9,482	[2]	'		'
Capitalized interest	$2,148		'		$5,678		'		'
[1]	The liability component is the difference between the net proceeds and the equity component of a convertible note that can be settled in a combination of cash and shares of stock at the election of the issuer. The equity component represents the conversion feature of a convertible note and is treated as original issue discount in addition to the underwriting discount. The liability component includes the periodic amortization of the additional discount.
[2]	Interest cost includes the coupon interest, the accretion of the liability component, the accretion of the underwriting discount and the amortization of the issuance costs allocated to the liability component.

Income_Taxes_Details

Income Taxes (Details) (USD $)	3 Months Ended			9 Months Ended		3 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Mar. 31, 2013	Sep. 30, 2013
						Foreign Tax Authority [Member]	Statute Of Limitations Expiration And Possible Settements With Taxing Authorities [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]	'	'	'	'	'	'	'
Effective income tax rate reconciliation, percent	'	'	'	19.11%	'	'	'
(Loss) income before income taxes and equity earnings	($76,181,000)	'	($42,985,000)	($203,681,000)	($142,292,000)	'	'
Deferred tax liabilities, net	116,700,000	'	'	116,700,000	'	'	'
Valuation allowance	64,800,000	'	'	64,800,000	'	'	'
Foreign subsidiary earnings and withholding taxes	21,700,000	'	'	21,700,000	'	'	'
Deferred income tax expense due to elimination of intercompany balances and transactions	3,100,000	'	'	3,100,000	'	'	'
Income tax payable due to elimination of intercompany balances and transactions	3,100,000	'	'	3,100,000	'	'	'
Unrecognized tax benefits	1,600,000	'	'	1,600,000	'	'	'
Unrecognized tax benefits, decrease resulting from settlements with taxing authorities	'	4,700,000	'	'	'	'	'
Significant change in unrecognized tax benefits is reasonably possible, estimated range of change, lower bound	'	'	'	'	'	'	700,000
Increase (decrease) in deferred income taxes	'	'	'	'	'	2,900,000	'
Decrease in deferred tax liabilities as a result of the American Taxpayer Relief Act	'	'	'	'	'	$5,800,000	'

Stockholders_Equity_Details

Stockholders' Equity (Details) (USD $)

9 Months Ended

0 Months Ended

1 Months Ended

9 Months Ended

16 Months Ended

1 Months Ended

3 Months Ended

9 Months Ended

Sep. 30, 2013

Sep. 30, 2012

Jun. 11, 2012

Sep. 30, 2013

Jan. 30, 2013

Jan. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2012

Jan. 30, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Sep. 30, 2013

MCP Exchangeco Inc. [Member]

Convertible Debt [Member]

Convertible Debt [Member]

Common Stock [Member]

Common Stock [Member]

Common Stock [Member]

Common Stock [Member]

Common Stock [Member]

Series A Mandatory Convertible Preferred Stock [Member]

Series A Mandatory Convertible Preferred Stock [Member]

Series A Mandatory Convertible Preferred Stock [Member]

Series A Mandatory Convertible Preferred Stock [Member]

5.50% Convertible Notes, Net Of Discount, Due February 2018 [Member]

5.50% Convertible Notes, Net Of Discount, Due February 2018 [Member]

Officers, Directors And Other Related Parties [Member]

Class of Stock [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Shares outstanding

'

'

'

'

'

'

188,624,415

188,624,415

138,773,538

'

2,070,000

'

'

2,070,000

Dividend rate

'

'

'

'

'

'

'

'

'

'

'

'

'

5.50%

Cash dividend declared (in dollars per share)

'

'

'

'

'

'

'

'

'

'

$1.38

$1.38

$1.38

'

Cash dividend declared and paid

$8,539,000

$8,539,000

'

'

'

'

'

'

'

'

$2,800,000

$2,800,000

$2,800,000

'

Stock issued during the period, shares

'

'

'

'

'

37,500,000

'

'

'

'

'

'

'

'

Offering price per share (in dollars per share)

'

'

'

'

'

$6

'

'

'

'

'

'

'

'

Shares issued for underwriters option to purchase within 30 days

'

'

'

'

'

5,625,000

'

'

'

'

'

'

'

'

Underwriters' offering price per share (in dollars per share)

'

'

'

'

'

$6

'

'

'

'

'

'

'

'

Shares issued for underwriter's fees

'

'

'

'

'

6.00%

'

'

'

'

'

'

'

'

Shares issued for purchased by related parties

'

'

'

'

'

'

'

'

'

15,016,666

'

'

'

'

Underwriter fees

'

'

'

'

'

'

'

'

'

0

'

'

'

'

Net proceeds from sale of common stock

248,150,000

132,471,000

'

'

'

248,600,000

'

'

'

'

'

'

'

'

Interest rate

'

'

'

5.50%

5.50%

'

'

'

'

'

'

'

'

'

Owner-share lending aggreement shares offered in registered public offering

'

'

'

'

'

7,666,666

'

'

'

'

'

'

'

'

Number of borrowed shares

'

'

'

'

'

6,666,666

'

'

'

'

'

'

'

'

Own-share lending arrangement, shares, issued, offered in registered public offering, price per share

'

'

'

'

'

$6

'

'

'

'

'

'

'

'

Proceeds from own-share lending arrangement, shares offered

'

'

'

'

'

$0

'

'

'

'

'

'

'

'

Common stock issued to acquire the entity (in shares)

'

'

507,203

'

'

'

'

'

'

'

'

'

'

'

Exchangeable shares converted

'

'

'

'

'

'

12,971

353,167

'

'

'

'

'

'

Loss_Per_Share_Details

Loss Per Share (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Loss Per Share [Abstract]	'	'	'	'
Net loss attributable to Molycorp stockholders	($69,929)	($18,891)	($180,072)	($89,976)
Dividends on Convertible Preferred Stock	-2,846	-2,846	-8,539	-8,539
Loss attributable to common stockholders	-72,775	-21,737	-188,611	-98,515
Continuing operations	-68,589	-20,977	-183,421	-97,655
Discontinued operations	($4,186)	($760)	($5,190)	($860)
Weighted average common shares outstanding—basic	168,114,266	117,086,022	163,222,000	101,147,638
Basic loss per share, Continuing operations (in dollars per share)	($0.41)	($0.18)	($1.12)	($0.97)
Basic loss per share, Discontinued operations (in dollars per share)	($0.02)	($0.01)	($0.03)	($0.01)
Basic (in dollars per share)	($0.43)	($0.19)	($1.16)	($0.97)
Diluted loss per share, Continuing operations (in dollars per share)	($0.41)	($0.18)	($1.12)	($0.97)
Diluted loss per share, Discontinued operations (in dollars per share)	($0.02)	($0.01)	($0.03)	($0.01)
Diluted (in dollars per share)	($0.43)	($0.19)	($1.16)	($0.97)

StockBased_Compensation_Narrat

Stock-Based Compensation (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Allocated share-based compensation expense	$1.60	$1	$2.40	$2.90
Forfeitures amount recognized in the period included in stock-based compensation expense	0.2	'	1.4	'
RSUs [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Matching contribution by entity as percentage of converted restricted stock	25.00%	25.00%	25.00%	25.00%
Molycorp ESPP [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Allocated share-based compensation expense	'	'	$0.10	'

StockBased_Compensation_Summar

Stock-Based Compensation (Summary Of Activity Related To Stock-Based Awards) (Details) (USD $)	9 Months Ended
	Sep. 30, 2013
PBRSUs [Member]	'
Number of Shares	'
Unvested at the beginning of the period (in shares)	29,302
Granted (in shares)	897,515
Forfeited (in shares)	-65,143
Unvested at the end of the period (in shares)	861,674
Weighted Average Grant-Date Price	'
Unvested shares at the beginning of the period (in dollars per share)	$30.33
Granted (in dollars per share)	$6.76
Forfeited (in dollars per share)	$11.17
Unvested shares at the end of the period (in dollars per share)	$7.23
RSUs [Member]	'
Number of Shares	'
Unvested at the beginning of the period (in shares)	181,602
Granted (in shares)	997,979
Forfeited (in shares)	-80,510
Vested (in shares)	-19,632	[1]
Unvested at the end of the period (in shares)	1,079,439
Weighted Average Grant-Date Price	'
Unvested shares at the beginning of the period (in dollars per share)	$32.15
Granted (in dollars per share)	$7.04
Forfeited (in dollars per share)	$28.06
Vested (in dollars per share)	$7.56	[1]
Unvested shares at the end of the period (in dollars per share)	$9.82
Restricted Stock [Member]	'
Number of Shares	'
Unvested at the beginning of the period (in shares)	39,974
Forfeited (in shares)	-8,143
Unvested at the end of the period (in shares)	31,831
Weighted Average Grant-Date Price	'
Unvested shares at the beginning of the period (in dollars per share)	$40.09
Forfeited (in dollars per share)	$39.76
Unvested shares at the end of the period (in dollars per share)	$37.87
[1]	Includes deferral and conversion of a portion of fees payable to certain non-employee directors of the Company.

StockBased_Compensation_Summar1

Stock-Based Compensation (Summary Of The Activity And Other Information Related To Stock Option Awards) (Details) (USD $)	9 Months Ended
	Sep. 30, 2013
Number of Shares	'
Outstanding at beginning of period (in shares)	35,624
Forfeited and expired (in shares)	-9,008
Outstanding at end of period (in shares)	26,616
Options exercisable at period end (in shares)	17,744
Weighted Average Exercise Price	'
Outstanding at beginning of period (in dollars per share)	$48.87
Forfeited and expired (in dollars per share)	$48.87
Outstanding at end of period (in dollars per share)	$48.87
Options exercisable at period end (in dollars per share)	$48.87

Commitments_And_Contingencies_1

Commitments And Contingencies (Narrative) (Details) (USD $)	Sep. 30, 2013	Aug. 31, 2013	Jul. 31, 2012	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013
In Millions, unless otherwise specified	employee	Purported Class Action [Member]	Consolidated Class Action [Member]	Derivative Lawsuits And Investigations [Member]	Molycorp Mountain Pass Facility [Member]	Molycorp Silmet [Member]
		lawsuit	claim	lawsuit	Employees Covered By Collective Bargaining Agreement Under Facility [Member]	Employees Covered By Collective Bargaining Agreement Under Facility [Member]
					Workforce [Member]	Workforce [Member]
					employee	employee
Commitments And Contingencies [Line Items]	'	'	'	'	'	'
Number of employees	2,650	'	'	'	237	174
Concentration risk (as a percent)	'	'	'	'	61.00%	30.00%
Surety bonds placed to secure the closure and reclamation obligations	$28.80	'	'	'	'	'
Number of lawsuits	'	2	'	'	'	'
Number of pending claims	'	'	18	'	'	'
Number of lawsuits dismissed	'	'	'	2	'	'

Commitments_And_Contingencies_2

Commitments And Contingencies (Schedule Of Future Minimum Rental Payments For Operating Leases) (Details) (Office Space, Trailers And Certain Equipment [Member], USD $)	Sep. 30, 2013
In Thousands, unless otherwise specified
Office Space, Trailers And Certain Equipment [Member]	'
Remaining annual minimum payments under operating leases	'
Total	$6,966
Less Than 1 Year	2,667
1 - 3 Years	2,824
4 - 5 Years	437
More Than 5 Years	$1,038

Commitments_And_Contingencies_3

Commitments And Contingencies (Schedule Of Minimum Payments For Purchase Obligations) (Details) (USD $)	Sep. 30, 2013
In Thousands, unless otherwise specified
Commitments And Contingencies [Abstract]	'
Total	$251,361
Less Than 1 Year	227,365
1 - 3 Years	13,206
4 - 5 Years	6,487
More Than 5 Years	$4,303

Concentrations_Details

Concentrations (Details) (USD $)

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

In Thousands, unless otherwise specified

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2012

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Product Concentration [Member]

Product Concentration [Member]

Product Concentration [Member]

Product Concentration [Member]

Product Concentration [Member]

Product Concentration [Member]

Product Concentration [Member]

Product Concentration [Member]

Product Concentration [Member]

Product Concentration [Member]

Daido Electronics [Member]

Daido Electronics [Member]

Resources [Member]

Chemicals And Oxides [Member]

Chemicals And Oxides [Member]

Chemicals And Oxides [Member]

Chemicals And Oxides [Member]

Chemicals And Oxides [Member]

Magnetic Materials And Alloys [Member]

Magnetic Materials And Alloys [Member]

Magnetic Materials And Alloys [Member]

Magnetic Materials And Alloys [Member]

Magnetic Materials And Alloys [Member]

Magnetic Materials And Alloys [Member]

Neodymium And Praseodymium Products [Member]

Neodymium And Praseodymium Products [Member]

Cerium Products [Member]

Cerium Products [Member]

Cerium Products [Member]

Cerium Products [Member]

Neo Powders [Member]

Neo Powders [Member]

Neo Powders [Member]

Neo Powders [Member]

Neo Powders [Member]

Neo Powders [Member]

Concentration Risk [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Entity-wide revenue, major customers

'

'

'

'

10.00%

12.00%

8.00%

16.00%

10.00%

11.00%

45.00%

34.00%

22.00%

40.00%

'

'

Sales, net of intercompany transactions

$149,066

$205,205

$430,580

$394,085

'

'

'

'

'

'

'

'

'

'

$16,300

$39,200

RelatedParty_Transactions_Deta

Related-Party Transactions (Details) (USD $)	3 Months Ended			9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2012	Sep. 30, 2013
Neo Powders [Member] | TMT [Member]	'	'	'	'
Related Party Transaction [Line Items]	'	'	'	'
Sales to related party	$0.70	$1.30	$1.40	$2.70
Compounds [Member] | TMT [Member]	'	'	'	'
Related Party Transaction [Line Items]	'	'	'	'
Purchases made from related party	0.6	1.4	1.9	1.5
Metals [Member] | Keli [Member]	'	'	'	'
Related Party Transaction [Line Items]	'	'	'	'
Purchases made from related party	20.4	16.1	21.4	44.8
Gallium Metal [Member] | Ingal Stade [Member]	'	'	'	'
Related Party Transaction [Line Items]	'	'	'	'
Purchases made from related party	1.1	1.3	1.7	3.4
Daido Electronics [Member] | Neo Powders [Member] | Ingal Stade [Member]	'	'	'	'
Related Party Transaction [Line Items]	'	'	'	'
Sales to related party	$16.30	'	'	$39.20

Recovered_Sheet3

Net Change in Operating Assets and Liabilities (Details) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Decrease (increase) in operating assets:	'	'
Accounts receivable	($5,557)	$88,997
Inventory	26,816	13,202
Prepaid expenses and other assets	-1,085	7,174
Increase (decrease) in operating liabilities:	'	'
Accounts payable	-16,642	-43,223
Income tax payable	-8,768	-39,483
Interest payable	-26,765	-9,704
Asset retirement obligation	-2,385	'
Accrued expenses	-10,826	-49,044
Net change in operating assets and liabilities	($45,212)	($32,081)

Derivative_Instruments_Narrati

Derivative Instruments (Narrative) (Details)	3 Months Ended		3 Months Ended		9 Months Ended	0 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2013	Mar. 28, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Jun. 11, 2012	Sep. 30, 2013	Mar. 28, 2012
	USD ($)	CAD	Interest Expense [Member]	Interest Expense [Member]	Interest Expense [Member]	Other Expense [Member]	Derivative Liability [Member]	Molycorp Canada [Member]
			USD ($)	USD ($)	USD ($)	USD ($)	USD ($)	CAD
Fair Value, Option, Quantitative Disclosures [Line Items]	'	'	'	'	'	'	'	'
Fair value of put option	'	'	'	'	'	'	$6.80	'
Unrealized gain (loss) on change in put option fair value	'	'	-0.2	0.2	1	'	'	'
Notional amount of derivatives	'	870	'	'	'	'	'	870
Realized loss on settlement of derivative forward contracts	$6.70	'	'	'	'	$37.60	'	'

Employee_Benefit_Plans_And_Sev2

Employee Benefit Plans And Severance Charges (Employee Benefit Plans) (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Employee Benefit Plans And Severance Charges [Abstract]	'	'	'	'
Company matching contribution as a percentage of the first 3.0% compensation contributed by each eligible employee	100.00%	'	100.00%	'
Percentage of each employee's compensation eligible for Compoany match of 100% in defined contribution plan	3.00%	'	3.00%	'
Company matching contribution as a percentage of the next 2.0% of compensation contributed by each eligible employee	50.00%	'	50.00%	'
Percentage of each employee's compensation eligible for Company match of 50% in defined contribution plan	2.00%	'	2.00%	'
Safe harbor matching contribution vesting percentage	100.00%	'	100.00%	'
Vesting percentage of discretionary matching contribution after 3 years of service	100.00%	'	100.00%	'
Period of service after which employees vest in Company contributions	'	'	'3 years	'
Expenses related to defined contribution plan	$0.70	$0.40	$2.20	$1
Estimated future employer contributions in 2013	'	'	$0.20	'

Employee_Benefit_Plans_And_Sev3

Employee Benefit Plans And Severance Charges (Schedule Of Net Benefit Costs) (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013
Components of net periodic benefit cost:	'	'	'
Interest cost	$80	$90	$240
Expected return on plan assets	-68	-67	-203
Amortization of prior service cost	-1	-1	-3
Amortization of actuarial loss	61	55	183
Net periodic benefit cost	72	77	217
Pension Plan [Member]	'	'	'
Components of net periodic benefit cost:	'	'	'
Interest cost	78	90	234
Expected return on plan assets	-68	-67	-203
Amortization of prior service cost	'	-1	'
Amortization of actuarial loss	63	55	189
Net periodic benefit cost	73	77	220
PBP [Member]	'	'	'
Components of net periodic benefit cost:	'	'	'
Interest cost	2	'	6
Amortization of prior service cost	-1	'	-3
Amortization of actuarial loss	-2	'	-6
Net periodic benefit cost	($1)	'	($3)

Employee_Benefit_Plans_And_Sev4

Employee Benefit Plans And Severance Charges (Severance Charges) (Narrative) (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2013	Jul. 31, 2013
		Selling, General And Administrative Expenses [Member]	Molycorp Napanee [Member]
Restructuring Cost and Reserve [Line Items]	'	'	'
Restructuring charges	'	$2.10	'
Restructuring reserve settled with cash	1.6	'	'
Discontinued operations recognized severance and benefit costs	'	'	$0.10

Subsidiary_Guarantor_Financial2

Subsidiary Guarantor Financial Information (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Other income (expense)	($657)	($57)	$1,430	($37,615)
Parent [Member]	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Other income (expense)	4	'	4	-37,589
Guarantor Subsidiaries [Member]	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Intercompany advances owed	'	'	356,867	680,966
Other income (expense)	64	-68	298	27
Non-Guarantor Subsidiaries [Member]	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Intercompany advances owed	'	'	81,507	111,743
Other income (expense)	($725)	$11	$1,128	($53)

Subsidiary_Guarantor_Financial3

Subsidiary Guarantor Financial Information (Schedule Of Condensed Consolidating Balance Sheet) (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified
Current assets:	'	'	'	'
Cash and cash equivalents	$173,914	$227,790	$436,025	$418,855
Trade accounts receivable, net	58,200	52,430	'	'
Inventory	183,441	287,376	'	'
Deferred charges	3,080	9,412	'	'
Deferred tax assets	8,478	9,789	'	'
Income tax receivable	20,296	25,087	'	'
Prepaid expenses and other current assets	25,660	21,794	'	'
Total current assets	473,069	633,678	'	'
Non-current assets:	'	'	'	'
Deposits	25,997	26,769	'	'
Property, plant and equipment, net	1,779,084	1,544,304	'	'
Inventory	24,325	26,096	'	'
Intangible assets, net	419,471	450,938	'	'
Investments	58,749	64,036	'	'
Goodwill	239,742	239,742	'	'
Other non-current assets	6,839	6,972	'	'
Total non-current assets	2,554,207	2,358,857	'	'
Total assets	3,027,276	2,992,535	'	'
Current liabilities:	'	'	'	'
Trade accounts payable	107,882	241,994	'	'
Accrued expenses	61,445	59,013	'	'
Income tax payable	1,708	15,267	'	'
Debt and capital lease obligations	16,673	39,604	'	'
Other current liabilities	6,689	3,539	'	'
Total current liabilities	194,397	359,417	'	'
Non-current liabilities:	'	'	'	'
Asset retirement obligation	14,084	18,586	'	'
Deferred tax liabilities	125,142	160,675	'	'
Debt and capital lease obligations	1,356,256	1,188,832	'	'
Derivative liability	6,819	7,816	'	'
Pension liabilities	3,431	3,292	'	'
Other non-current liabilities	2,052	2,659	'	'
Total non-current liabilities	1,507,784	1,381,860	'	'
Total liabilities	1,702,181	1,741,277	'	'
Stockholders’ equity:	'	'	'	'
Common stock	189	139	'	'
Preferred stock	2	2	'	'
Additional paid-in capital	1,946,742	1,691,429	'	'
Accumulated other comprehensive loss	-7,848	-9,433	'	'
Accumulated deficit	-646,163	-466,091	'	'
Total Molycorp stockholders’ equity	1,292,922	1,216,046	'	'
Noncontrolling interests	32,173	35,212	'	'
Total stockholders’ equity	1,325,095	1,251,258	1,656,134	845,230
Total liabilities and stockholders’ equity	3,027,276	2,992,535	'	'
Parent [Member]	'	'	'	'
Current assets:	'	'	'	'
Cash and cash equivalents	31,207	16,560	175,400	407,446
Total current assets	31,207	16,560	'	'
Non-current assets:	'	'	'	'
Deposits	1,754	1,752	'	'
Deferred tax assets	'	6,030	'	'
Investments in consolidated subsidiaries	699,379	883,319	'	'
Intercompany accounts receivable	1,920,116	1,539,877	'	'
Total non-current assets	2,621,249	2,430,978	'	'
Total assets	2,652,456	2,447,538	'	'
Current liabilities:	'	'	'	'
Accrued expenses	27,695	14,872	'	'
Total current liabilities	27,695	14,872	'	'
Non-current liabilities:	'	'	'	'
Debt and capital lease obligations	1,331,839	1,166,777	'	'
Intercompany accounts payable	'	49,843	'	'
Total non-current liabilities	1,331,839	1,216,620	'	'
Total liabilities	1,359,534	1,231,492	'	'
Stockholders’ equity:	'	'	'	'
Common stock	189	139	'	'
Preferred stock	2	2	'	'
Additional paid-in capital	1,946,742	1,691,429	'	'
Accumulated other comprehensive loss	-7,848	-9,433	'	'
Accumulated deficit	-646,163	-466,091	'	'
Total Molycorp stockholders’ equity	1,292,922	1,216,046	'	'
Total stockholders’ equity	1,292,922	1,216,046	'	'
Total liabilities and stockholders’ equity	2,652,456	2,447,538	'	'
Guarantor Subsidiaries [Member]	'	'	'	'
Current assets:	'	'	'	'
Cash and cash equivalents	8,914	18,020	3,830	10,758
Trade accounts receivable, net	3,012	7,738	'	'
Inventory	34,044	49,416	'	'
Deferred charges	1,329	2,203	'	'
Income tax receivable	20,243	25,087	'	'
Prepaid expenses and other current assets	9,559	9,085	'	'
Total current assets	77,101	111,549	'	'
Non-current assets:	'	'	'	'
Deposits	24,243	24,862	'	'
Property, plant and equipment, net	1,620,346	1,377,147	'	'
Inventory	24,325	26,096	'	'
Intangible assets, net	459	508	'	'
Investments	43,425	45,241	'	'
Investments in consolidated subsidiaries	122,784	97,960	'	'
Intercompany accounts receivable	'	207,035	'	'
Other non-current assets	785	885	'	'
Total non-current assets	1,836,367	1,779,734	'	'
Total assets	1,913,468	1,891,283	'	'
Current liabilities:	'	'	'	'
Trade accounts payable	70,498	191,769	'	'
Accrued expenses	12,375	10,087	'	'
Income tax payable	7	'	'	'
Deferred tax liabilities	'	1,942	'	'
Debt and capital lease obligations	1,861	352	'	'
Other current liabilities	6,689	3,539	'	'
Total current liabilities	91,430	207,689	'	'
Non-current liabilities:	'	'	'	'
Asset retirement obligation	14,084	18,586	'	'
Deferred tax liabilities	'	23,130	'	'
Debt and capital lease obligations	18,850	15,163	'	'
Intercompany accounts payable	1,916,264	1,577,363	'	'
Other non-current liabilities	1,340	1,102	'	'
Total non-current liabilities	1,950,538	1,635,344	'	'
Total liabilities	2,041,968	1,843,033	'	'
Stockholders’ equity:	'	'	'	'
Additional paid-in capital	149,857	149,857	'	'
Accumulated deficit	-278,357	-101,607	'	'
Total Molycorp stockholders’ equity	-128,500	48,250	'	'
Total stockholders’ equity	-128,500	48,250	'	'
Total liabilities and stockholders’ equity	1,913,468	1,891,283	'	'
Non-Guarantor Subsidiaries [Member]	'	'	'	'
Current assets:	'	'	'	'
Cash and cash equivalents	133,793	193,210	256,795	651
Trade accounts receivable, net	55,188	44,692	'	'
Inventory	149,397	237,960	'	'
Deferred charges	1,751	7,209	'	'
Deferred tax assets	8,478	11,731	'	'
Income tax receivable	53	'	'	'
Prepaid expenses and other current assets	16,101	12,709	'	'
Total current assets	364,761	507,511	'	'
Non-current assets:	'	'	'	'
Deposits	'	155	'	'
Property, plant and equipment, net	158,738	167,157	'	'
Intangible assets, net	419,012	450,430	'	'
Investments	15,324	18,795	'	'
Goodwill	239,742	239,742	'	'
Intercompany accounts receivable	791	794	'	'
Other non-current assets	6,054	6,087	'	'
Total non-current assets	839,661	883,160	'	'
Total assets	1,204,422	1,390,671	'	'
Current liabilities:	'	'	'	'
Trade accounts payable	37,384	50,225	'	'
Accrued expenses	21,375	34,054	'	'
Income tax payable	8,432	15,267	'	'
Debt and capital lease obligations	14,812	39,252	'	'
Total current liabilities	82,003	138,798	'	'
Non-current liabilities:	'	'	'	'
Deferred tax liabilities	118,411	143,575	'	'
Debt and capital lease obligations	5,567	6,892	'	'
Derivative liability	6,819	7,816	'	'
Pension liabilities	3,431	3,292	'	'
Intercompany accounts payable	4,643	120,500	'	'
Other non-current liabilities	712	1,557	'	'
Total non-current liabilities	139,583	283,632	'	'
Total liabilities	221,586	422,430	'	'
Stockholders’ equity:	'	'	'	'
Additional paid-in capital	1,316,079	1,283,863	'	'
Accumulated other comprehensive loss	-7,848	-9,433	'	'
Accumulated deficit	-357,568	-341,401	'	'
Total Molycorp stockholders’ equity	950,663	933,029	'	'
Noncontrolling interests	32,173	35,212	'	'
Total stockholders’ equity	982,836	968,241	'	'
Total liabilities and stockholders’ equity	1,204,422	1,390,671	'	'
Eliminations [Member]	'	'	'	'
Current assets:	'	'	'	'
Deferred tax assets	'	-1,942	'	'
Total current assets	'	-1,942	'	'
Non-current assets:	'	'	'	'
Deferred tax assets	'	-6,030	'	'
Investments in consolidated subsidiaries	-822,163	-981,279	'	'
Intercompany accounts receivable	-1,920,907	-1,747,706	'	'
Total non-current assets	-2,743,070	-2,735,015	'	'
Total assets	-2,743,070	-2,736,957	'	'
Current liabilities:	'	'	'	'
Income tax payable	-6,731	'	'	'
Deferred tax liabilities	'	-1,942	'	'
Total current liabilities	-6,731	-1,942	'	'
Non-current liabilities:	'	'	'	'
Deferred tax liabilities	6,731	-6,030	'	'
Intercompany accounts payable	-1,920,907	-1,747,706	'	'
Total non-current liabilities	-1,914,176	-1,753,736	'	'
Total liabilities	-1,920,907	-1,755,678	'	'
Stockholders’ equity:	'	'	'	'
Additional paid-in capital	-1,465,936	-1,433,720	'	'
Accumulated other comprehensive loss	7,848	9,433	'	'
Accumulated deficit	635,925	443,008	'	'
Total Molycorp stockholders’ equity	-822,163	-981,279	'	'
Total stockholders’ equity	-822,163	-981,279	'	'
Total liabilities and stockholders’ equity	($2,743,070)	($2,736,957)	'	'

Subsidiary_Guarantor_Financial4

Subsidiary Guarantor Financial Information (Schedule Of Condensed Consolidating Statement Of Operations And Comprehensive Loss) (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Revenues	$149,066	$205,205	$430,580	$394,085
Costs of sales:	'	'	'	'
Costs excluding depreciation and amortization	-150,444	-183,227	-421,699	-336,654
Depreciation and amortization	-16,400	-10,612	-49,283	-19,065
Gross (loss) profit	-17,778	11,366	-40,402	38,366
Operating expenses:	'	'	'	'
Selling, general and administrative	-24,399	-31,349	-76,446	-78,583
Corporate development	-69	-1,073	-256	-19,379
Depreciation, amortization and accretion	-10,072	-9,584	-26,273	-12,188
Research and development	-5,565	-8,929	-18,476	-18,628
Impairment of goodwill and other long-lived assets	-1,118	'	-1,495	'
Operating loss	-59,001	-39,569	-163,348	-90,412
Other (expense) income:	'	'	'	'
Other income (expense)	-657	-57	1,430	-37,615
Foreign exchange (loss) gain, net	-234	1,910	1,044	724
Interest (expense) income, net	-16,289	-5,269	-42,807	-14,989
Total other expense	-17,180	-3,416	-40,333	-51,880
Loss before income taxes and equity earnings	-76,181	-42,985	-203,681	-142,292
Income tax benefit	12,902	28,956	38,922	58,442
Equity in results of affiliates	-2,334	-662	-8,690	-1,146
Loss from continuing operations	-65,613	-14,691	-173,449	-84,996
Loss from discontinued operations, net of tax	-4,186	-760	-5,190	-860
Net loss	-69,799	-15,451	-178,639	-85,856
Net income attributable to noncontrolling interest	-130	-3,440	-1,433	-4,120
Net loss attributable to Molycorp stockholders	-69,929	-18,891	-180,072	-89,976
Other comprehensive income:	'	'	'	'
Foreign currency translation adjustments	4,217	526	1,585	-1,165
Comprehensive loss	-65,582	-14,925	-177,054	-87,021
Comprehensive loss attributable to:	'	'	'	'
Molycorp stockholders	-65,452	-11,485	-175,621	-82,901
Noncontrolling interest	-130	-3,440	-1,433	-4,120
Parent [Member]	'	'	'	'
Operating expenses:	'	'	'	'
Selling, general and administrative	-3	-29	-3	45
Corporate development	'	'	'	-46
Operating loss	-3	-29	-3	-1
Other (expense) income:	'	'	'	'
Other income (expense)	4	'	4	-37,589
Foreign exchange (loss) gain, net	1,727	'	1,727	'
Interest (expense) income, net	-14,093	-2,920	-39,978	-12,602
Interest income (expense) from intercompany notes	9,211	453	27,455	1,326
Equity loss from consolidated subsidiaries	-54,858	-16,395	-163,247	-55,770
Total other expense	-58,009	-18,862	-174,039	-104,635
Loss before income taxes and equity earnings	-58,012	-18,891	-174,042	-104,636
Income tax benefit	-11,914	'	-6,030	14,660
Loss from continuing operations	-69,926	-18,891	-180,072	-89,976
Net loss	-69,926	-18,891	-180,072	-89,976
Net loss attributable to Molycorp stockholders	-69,926	-18,891	-180,072	-89,976
Other comprehensive income:	'	'	'	'
Comprehensive loss	-69,926	-18,891	-180,072	-89,976
Comprehensive loss attributable to:	'	'	'	'
Molycorp stockholders	-69,926	-18,891	-180,072	-89,976
Guarantor Subsidiaries [Member]	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Revenues	19,237	26,103	68,014	121,172
Costs of sales:	'	'	'	'
Costs excluding depreciation and amortization	-55,517	-38,919	-147,209	-105,185
Depreciation and amortization	-9,336	-3,375	-28,523	-7,539
Gross (loss) profit	-45,616	-16,191	-107,718	8,448
Operating expenses:	'	'	'	'
Selling, general and administrative	-15,554	-20,147	-48,870	-62,746
Corporate development	-69	-1,073	-256	-19,333
Depreciation, amortization and accretion	-1,597	-742	-3,258	-1,441
Research and development	-1,037	-2,497	-4,428	-10,584
Operating loss	-63,873	-40,650	-164,530	-85,656
Other (expense) income:	'	'	'	'
Other income (expense)	64	-68	298	27
Foreign exchange (loss) gain, net	-1	-3	8	-5
Interest (expense) income, net	-744	-1,076	-5,039	-194
Interest income (expense) from intercompany notes	1,412	-324	4,293	-967
Equity loss from consolidated subsidiaries	-333	4,090	-6,742	-18,302
Total other expense	398	2,619	-7,182	-19,441
Loss before income taxes and equity earnings	-63,475	-38,031	-171,712	-105,097
Income tax benefit	14,879	23,537	23,130	37,302
Equity in results of affiliates	-1,617	-682	-5,239	-1,475
Loss from continuing operations	-50,213	-15,176	-153,821	-69,270
Net loss	-50,213	-15,176	-153,821	-69,270
Net loss attributable to Molycorp stockholders	-50,213	-15,176	-153,821	-69,270
Other comprehensive income:	'	'	'	'
Comprehensive loss	-50,213	-15,176	-153,821	-69,270
Comprehensive loss attributable to:	'	'	'	'
Molycorp stockholders	-50,213	-15,176	-153,821	-69,270
Non-Guarantor Subsidiaries [Member]	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Revenues	142,421	191,661	397,548	293,228
Costs of sales:	'	'	'	'
Costs excluding depreciation and amortization	-107,519	-156,867	-309,472	-251,784
Depreciation and amortization	-7,064	-7,237	-20,760	-11,526
Gross (loss) profit	27,838	27,557	67,316	29,918
Operating expenses:	'	'	'	'
Selling, general and administrative	-8,842	-11,173	-27,573	-15,882
Depreciation, amortization and accretion	-8,475	-8,842	-23,015	-10,747
Research and development	-4,528	-6,432	-14,048	-8,044
Impairment of goodwill and other long-lived assets	-1,118	'	-1,495	'
Operating loss	4,875	1,110	1,185	-4,755
Other (expense) income:	'	'	'	'
Other income (expense)	-725	11	1,128	-53
Foreign exchange (loss) gain, net	-1,960	1,913	-691	729
Interest (expense) income, net	-1,452	-1,273	2,210	-2,193
Interest income (expense) from intercompany notes	-10,623	-129	-31,748	-359
Total other expense	-14,760	522	-29,101	-1,876
Loss before income taxes and equity earnings	-9,885	1,632	-27,916	-6,631
Income tax benefit	9,937	5,419	21,822	6,480
Equity in results of affiliates	-717	20	-3,451	329
Loss from continuing operations	-665	7,071	-9,545	178
Loss from discontinued operations, net of tax	-4,186	-760	-5,190	-860
Net loss	-4,851	6,311	-14,735	-682
Net income attributable to noncontrolling interest	-130	-3,440	-1,433	-4,120
Net loss attributable to Molycorp stockholders	-4,981	2,871	-16,168	-4,802
Other comprehensive income:	'	'	'	'
Foreign currency translation adjustments	4,217	526	1,585	-1,165
Comprehensive loss	-634	6,837	-13,150	-1,847
Comprehensive loss attributable to:	'	'	'	'
Molycorp stockholders	-504	10,277	-11,717	2,273
Noncontrolling interest	-130	-3,440	-1,433	-4,120
Eliminations [Member]	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Revenues	-12,592	-12,559	-34,982	-20,315
Costs of sales:	'	'	'	'
Costs excluding depreciation and amortization	12,592	12,559	34,982	20,315
Other (expense) income:	'	'	'	'
Equity loss from consolidated subsidiaries	55,191	12,305	169,989	74,072
Total other expense	55,191	12,305	169,989	74,072
Loss before income taxes and equity earnings	55,191	12,305	169,989	74,072
Loss from continuing operations	55,191	12,305	169,989	74,072
Net loss	55,191	12,305	169,989	74,072
Net loss attributable to Molycorp stockholders	55,191	12,305	169,989	74,072
Other comprehensive income:	'	'	'	'
Comprehensive loss	55,191	12,305	169,989	74,072
Comprehensive loss attributable to:	'	'	'	'
Molycorp stockholders	$55,191	$12,305	$169,989	$74,072

Subsidiary_Guarantor_Financial5

Subsidiary Guarantor Financial Information (Schedule Of Condensed Consolidating Statements Of Cash Flows) (Details) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Condensed Financial Statements, Captions [Line Items]	'	'
Net cash (used in) provided by operating activities	($90,013)	($47,188)
Cash flows from investing activities:	'	'
Cash paid in connection with acquisition, net of cash acquired	'	-591,011
Investment in joint ventures	-3,423	-28,130
Deposits	'	-516
Capital expenditures	-334,597	-644,683
Other investing activities	-364	4,953
Net cash used in investing activities	-338,384	-1,259,387
Cash flows from financing activities:	'	'
Capital contributions from stockholder	'	390,225
Proceeds from debt	'	9,456
Repayments of debt	-25,990	-228,431
Net proceeds from sale of common stock	248,150	132,471
Net proceeds from sale of Senior Notes	'	635,373
Issuance of Convertible Notes	165,600	395,712
Payments of preferred dividends	-8,539	-8,539
Dividend paid to noncontrolling interests	-4,472	'
Other financing activities	-797	-3,331
Net cash provided by financing activities	373,952	1,322,936
Effect of exchange rate changes on cash	569	809
Net change in cash and cash equivalents	-53,876	17,170
Cash and cash equivalents at beginning of the period	227,790	418,855
Cash and cash equivalents at end of period	173,914	436,025
Parent [Member]	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Net cash (used in) provided by operating activities	-2,990	-20,495
Cash flows from investing activities:	'	'
Loans to subsidiaries	'	-683,063
Intercompany advances made	-438,374	-792,709
Repayments from subsidiaries	'	34,327
Investment in subsidiaries	'	-350,000
Repayments of notes receivable from non-guarantor	38,000	'
Net cash used in investing activities	-400,374	-1,791,445
Cash flows from financing activities:	'	'
Capital contributions from stockholder	'	390,225
Net proceeds from sale of common stock	248,150	132,471
Net proceeds from sale of Senior Notes	'	635,373
Issuance of Convertible Notes	165,600	395,712
Payments of preferred dividends	-8,539	-8,539
Borrowings from non-guarantor	12,800	'
Borrowing from guarantor	'	37,589
Other financing activities	'	-2,937
Net cash provided by financing activities	418,011	1,579,894
Net change in cash and cash equivalents	14,647	-232,046
Cash and cash equivalents at beginning of the period	16,560	407,446
Cash and cash equivalents at end of period	31,207	175,400
Guarantor Subsidiaries [Member]	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Net cash (used in) provided by operating activities	-79,888	-57,987
Cash flows from investing activities:	'	'
Loans to parent	'	-37,589
Loans to non-guarantor	-1,300	'
Repayments of notes receivable from non-guarantor	'	100,000
Notes receivable to non-guarantor	'	-227,512
Repayments of notes receivable from non-guarantor	264	'
Investment in joint ventures	-3,423	-28,130
Deposits	'	-516
Capital expenditures	-320,829	-628,407
Net cash used in investing activities	-325,288	-822,154
Cash flows from financing activities:	'	'
Repayments of debt	'	-870
Borrowings from non-guarantor	40,000	'
Borrowing from parent	'	227,512
Repayments to parent	'	-34,327
Intercompany advances owed	356,867	680,966
Other financing activities	-797	-68
Net cash provided by financing activities	396,070	873,213
Net change in cash and cash equivalents	-9,106	-6,928
Cash and cash equivalents at beginning of the period	18,020	10,758
Cash and cash equivalents at end of period	8,914	3,830
Non-Guarantor Subsidiaries [Member]	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Net cash (used in) provided by operating activities	-7,135	31,294
Cash flows from investing activities:	'	'
Loans to parent	-12,800	'
Loans to guarantor	-40,000	'
Cash paid in connection with acquisition, net of cash acquired	'	-591,011
Capital expenditures	-13,768	-16,276
Other investing activities	-364	4,953
Net cash used in investing activities	-66,932	-602,334
Cash flows from financing activities:	'	'
Contribution from parent	'	350,000
Proceeds from debt	'	9,456
Repayments of debt	-25,990	-227,561
Dividend paid to noncontrolling interests	-4,472	'
Borrowing from parent	'	455,551
Borrowing from guarantor	1,300	227,512
Repayments to parent	-38,000	'
Intercompany advances owed	81,507	111,743
Repayments to guarantor	-264	-100,000
Other financing activities	'	-326
Net cash provided by financing activities	14,081	826,375
Effect of exchange rate changes on cash	569	809
Net change in cash and cash equivalents	-59,417	256,144
Cash and cash equivalents at beginning of the period	193,210	651
Cash and cash equivalents at end of period	133,793	256,795
Eliminations [Member]	'	'
Cash flows from investing activities:	'	'
Loans to subsidiaries	'	683,063
Loans to parent	12,800	37,589
Loans to guarantor	40,000	'
Intercompany advances made	438,374	792,709
Repayments from subsidiaries	'	-34,327
Loans to non-guarantor	1,300	'
Repayments of notes receivable from non-guarantor	'	-100,000
Investment in subsidiaries	'	350,000
Notes receivable to non-guarantor	'	227,512
Repayments of notes receivable from non-guarantor	-38,264	'
Net cash used in investing activities	454,210	1,956,546
Cash flows from financing activities:	'	'
Contribution from parent	'	-350,000
Borrowings from non-guarantor	-52,800	'
Borrowing from parent	'	-683,063
Borrowing from guarantor	-1,300	-265,101
Repayments to parent	38,000	34,327
Intercompany advances owed	-438,374	-792,709
Repayments to guarantor	264	100,000
Net cash provided by financing activities	($454,210)	($1,956,546)

Subsidiary_Guarantor_Financial6

Subsidiary Guarantor Financial Information (Schedule Of Error Corrections And Prior Period Adjustments - Cash Flow) (Details) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Net cash used in investing activities	$338,384	$1,259,387
Net cash provided by financing activities	373,952	1,322,936
Guarantor Subsidiaries [Member]	'	'
Loans to parent	'	-37,589
Net cash used in investing activities	325,288	822,154
Intercompany advances owed	356,867	680,966
Net cash provided by financing activities	396,070	873,213
Non-Guarantor Subsidiaries [Member]	'	'
Loans to parent	-12,800	'
Net cash used in investing activities	66,932	602,334
Intercompany advances owed	81,507	111,743
Net cash provided by financing activities	14,081	826,375
Scenario, Previously Reported [Member] | Guarantor Subsidiaries [Member]	'	'
Intercompany advances made	'	680,966
Net cash used in investing activities	'	103,599
Net cash provided by financing activities	'	192,247
Scenario, Previously Reported [Member] | Non-Guarantor Subsidiaries [Member]	'	'
Intercompany advances made	'	111,743
Net cash used in investing activities	'	490,591
Net cash provided by financing activities	'	714,632
Restatement Adjustment [Member] | Guarantor Subsidiaries [Member]	'	'
Intercompany advances made	'	-680,966
Loans to parent	'	-37,589
Net cash used in investing activities	'	718,555
Intercompany advances owed	'	680,966
Net cash provided by financing activities	'	680,966
Restatement Adjustment [Member] | Non-Guarantor Subsidiaries [Member]	'	'
Intercompany advances made	'	-111,743
Net cash used in investing activities	'	111,743
Intercompany advances owed	'	111,743
Net cash provided by financing activities	'	$111,743

Subsidiary_Guarantor_Financial7

Subsidiary Guarantor Financial Information (Schedule Of Error Corrections And Prior Period Adjustments - Cash Flow And Operations And Comprehensive Loss) (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Other income (expense)	($657)	($57)	$1,430	($37,615)
Loss before income taxes and equity earnings	-76,181	-42,985	-203,681	-142,292
Income tax benefit	12,902	28,956	38,922	58,442
Loss from continuing operations	-65,613	-14,691	-173,449	-84,996
Net cash (used in) provided by operating activities	'	'	-90,013	-47,188
Net cash provided by financing activities	'	'	373,952	1,322,936
Net cash used in investing activities	'	'	-338,384	-1,259,387
Parent [Member]	'	'	'	'
Other income (expense)	4	'	4	-37,589
Loss before income taxes and equity earnings	-58,012	-18,891	-174,042	-104,636
Income tax benefit	-11,914	'	-6,030	14,660
Equity loss from consolidated subsidiaries	-54,858	-16,395	-163,247	-55,770
Loss from continuing operations	-69,926	-18,891	-180,072	-89,976
Net cash (used in) provided by operating activities	'	'	-2,990	-20,495
Borrowing from guarantor	'	'	'	37,589
Intercompany advances made	'	'	-438,374	-792,709
Net cash provided by financing activities	'	'	418,011	1,579,894
Net cash used in investing activities	'	'	-400,374	-1,791,445
Guarantor Subsidiaries [Member]	'	'	'	'
Other income (expense)	64	-68	298	27
Loss before income taxes and equity earnings	-63,475	-38,031	-171,712	-105,097
Income tax benefit	14,879	23,537	23,130	37,302
Equity loss from consolidated subsidiaries	-333	4,090	-6,742	-18,302
Loss from continuing operations	-50,213	-15,176	-153,821	-69,270
Net cash (used in) provided by operating activities	'	'	-79,888	-57,987
Borrowing from parent	'	'	'	-227,512
Loans to parent	'	'	'	-37,589
Net cash provided by financing activities	'	'	396,070	873,213
Net cash used in investing activities	'	'	-325,288	-822,154
Scenario, Previously Reported [Member] | Parent [Member]	'	'	'	'
Loss before income taxes and equity earnings	'	'	'	-89,976
Equity loss from consolidated subsidiaries	'	'	'	-78,699
Net cash (used in) provided by operating activities	'	'	'	17,094
Net cash provided by financing activities	'	'	'	1,542,305
Scenario, Previously Reported [Member] | Guarantor Subsidiaries [Member]	'	'	'	'
Other income (expense)	'	'	'	-37,562
Loss before income taxes and equity earnings	'	'	'	-142,686
Income tax benefit	'	'	'	51,962
Loss from continuing operations	'	'	'	-92,199
Net cash (used in) provided by operating activities	'	'	'	-95,576
Intercompany advances made	'	'	'	680,966
Net cash provided by financing activities	'	'	'	192,247
Net cash used in investing activities	'	'	'	-103,599
Restatement Adjustment [Member] | Parent [Member]	'	'	'	'
Other income (expense)	'	'	'	-37,589
Loss before income taxes and equity earnings	'	'	'	-14,660
Income tax benefit	'	'	'	14,660
Equity loss from consolidated subsidiaries	'	'	'	22,929
Net cash (used in) provided by operating activities	'	'	'	-37,589
Borrowing from guarantor	'	'	'	37,589
Net cash provided by financing activities	'	'	'	37,589
Restatement Adjustment [Member] | Guarantor Subsidiaries [Member]	'	'	'	'
Other income (expense)	'	'	'	37,589
Loss before income taxes and equity earnings	'	'	'	37,589
Income tax benefit	'	'	'	-14,660
Loss from continuing operations	'	'	'	22,929
Net cash (used in) provided by operating activities	'	'	'	37,589
Loans to parent	'	'	'	-37,589
Intercompany advances made	'	'	'	-680,966
Net cash provided by financing activities	'	'	'	680,966
Net cash used in investing activities	'	'	'	($718,555)

Discontinued_Operations_Narrat

Discontinued Operations (Narrative) (Details) (Molycorp Napanee [Member])	Sep. 30, 2013
	acre
	property
Molycorp Napanee [Member]	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'
Number of buildings	2
Number of acres	2

Discontinued_Operations_Schedu

Discontinued Operations (Schedule Of Disposal Group Carrying Amounts) (Details) (USD $)	Sep. 30, 2013
In Thousands, unless otherwise specified
Discontinued Operations [Abstract]	'
Land	$50
Buildings	700
Equipment	750
Inventory	819
Carrying value of disposal group	$2,319

Discontinued_Operations_Schedu1

Discontinued Operations (Schedule Of Operating Results Included In Discontinued Operations) (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Discontinued Operations [Abstract]	'	'	'	'
Revenues	$216	$399	$1,931	$566
Costs of sales	-913	-901	-3,044	-1,115
Selling, general and administrative expenses	-34	-119	-307	-138
Depreciation	'	-139	-315	-173
Operating loss	-731	-760	-1,735	-860
Loss on assets impairment	-3,455	'	-3,455	'
Net loss	($4,186)	($760)	($5,190)	($860)

Subsequent_Events_Details

Subsequent Events (Details) (USD $)	9 Months Ended		0 Months Ended		1 Months Ended	0 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Oct. 21, 2013	Oct. 15, 2013	Nov. 30, 2013	Oct. 14, 2013
			Subsequent Event [Member]	Subsequent Event [Member]	Subsequent Event [Member]	Molymet [Member]
						Subsequent Event [Member]
Subsequent Event [Line Items]	'	'	'	'	'	'
Cash dividend declared (in dollars per share)	'	'	'	'	$1.38	'
Stock issued during the period, shares	'	'	51,750,000	'	'	'
Underwriters’ option to purchase shares within 30 days, shares	'	'	6,750,000	'	'	'
Underwriters' offering price per share (in dollars per share)	'	'	$5	'	'	'
Net proceeds from sale of common stock	$248,150,000	$132,471,000	$247,500,000	$247,500,000	'	'
Agreement to purchase stock at request of company, value	'	'	'	'	'	$50,000,000