Molycorp (MCPIQ) 10-K 16 Mar 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2014	Mar. 13, 2015	Jun. 30, 2014
Document and Entity Information [Abstract]
Entity Registrant Name	Molycorp, Inc.
Entity Central Index Key	1489137
Document Type	10-K
Document Period End Date	31-Dec-14
Amendment Flag	FALSE
Current Fiscal Year End Date	-19
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		277,955,182
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Public Float			$497,386,528

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$211,685	$314,317
Trade accounts receivable, net (Note 3)	44,575	61,757
Inventory (Note 5)	169,323	171,783
Prepaid expenses and other current assets	29,332	29,210
Total current assets	454,915	577,067
Non-current assets:
Deposits (Note 6)	31,078	25,997
Property, plant and equipment, net (Note 7)	1,707,970	1,762,874
Inventory (Note 5)	25,127	25,329
Intangible assets, net (Note 9)	215,871	330,867
Investments (Note 10)	8,801	48,875
Goodwill (Note 9)	102,808	228,750
Other non-current assets	29,416	7,043
Total non-current assets	2,121,071	2,429,735
Total assets	2,575,986	3,006,802
Current liabilities:
Trade accounts payable	40,842	84,449
Accrued expenses (Note 12)	51,966	48,501
Debt and capital lease obligations (Note 14)	12,560	16,362
Other current liabilities	4,686	4,063
Total current liabilities	110,054	153,375
Non-current liabilities:
Asset retirement obligation (Note 13)	17,799	16,966
Deferred tax liabilities (Note 15)	63,802	85,481
Debt and capital lease obligations (Note 14)	1,559,781	1,363,916
Other non-current liabilities	20,247	10,002
Total non-current liabilities	1,661,629	1,476,365
Total liabilities	1,771,683	1,629,740
Commitments and contingencies (Note 19)
Stockholders’ equity:
Common stock, $0.001 par value; 700,000,000 shares authorized at December 31, 2014 and 350,000,000 at December 31, 2013 (Note 16)	260	241
Preferred stock, $0.001 par value; 5,000,000 shares authorized at December 31, 2013 (Note 16)	0	2
Additional paid-in capital	2,245,478	2,194,405
Accumulated other comprehensive loss	-3,323	-6,451
Accumulated deficit	-1,445,408	-840,474
Total Molycorp stockholders’ equity	797,007	1,347,723
Noncontrolling interests	7,296	29,339
Total stockholders’ equity	804,303	1,377,062
Total liabilities and stockholders’ equity	$2,575,986	$3,006,802

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Common stock, par value	$0.00	$0.00
Common stock, authorized	700,000,000	350,000,000
Preferred stock, par value	$0	$0.00
Preferred stock, authorized	0	5,000,000

Consolidated_Statements_of_Ope

Consolidated Statements of Operations and Comprehensive Loss (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Revenues	$116,242	$123,937	$116,907	$118,526	$123,814	$149,066	$136,112	$145,398	$475,612	$554,390	$527,696
Costs of sales:
Costs excluding depreciation and amortization									-481,417	-553,831	-478,253
Depreciation and amortization									-93,782	-67,727	-30,621
Gross (loss) profit	-44,844	-15,078	-16,571	-23,094	-27,049	-17,778	-18,036	-4,305	-99,587	-67,168	18,822
Operating expenses:
Selling, general and administrative									-74,490	-107,169	-113,437
Corporate development									0	-247	-19,796
Depreciation, amortization and accretion									-29,879	-38,037	-22,187
Research and development									-15,265	-23,172	-27,796
Impairment of goodwill and other long-lived assets									-231,650	-120,898	-301,755
Operating loss									-450,871	-356,691	-466,149
Other (expense) income:
Other (expense) income									-5,092	1,886	-38,798
Foreign exchange (loss) gain, net									-3,146	-376	2,872
Interest expense, net of capitalized interest									-167,375	-67,684	-22,116
Gain on extinguishment of convertible notes, net	19,719								19,719	0	0
Impairment of investments at cost					-9,400				-12,000	-9,411	0
Total other expense									-167,894	-75,585	-58,042
Loss from continuing operations before income taxes and equity earnings	-343,375	-99,484	-89,724	-86,182	-228,592	-76,181	-70,254	-57,249	-618,765	-432,276	-524,191
Income tax benefit									22,594	70,943	54,075
Equity in loss of affiliates									-26,763	-9,169	-3,490
Loss from continuing operations									-622,934	-370,502	-473,606
Loss from discontinued operations, net of tax									0	-6,427	-1,737
Net loss	-347,938	-105,148	-83,850	-85,998	-198,288	-69,799	-70,689	-38,153	-622,934	-376,929	-475,343
Net loss (income) attributable to noncontrolling interests									18,000	2,546	-5,826
Net loss attributable to Molycorp stockholders	-329,795	-105,179	-83,899	-86,061	-194,308	-69,929	-71,175	-38,971	-604,934	-374,383	-481,169
Other comprehensive loss, net of tax:
Foreign currency translation adjustments									4,271	1,623	248
Actuarial (loss) gain									-1,143	1,359	-1,200
Comprehensive loss									-619,806	-373,947	-476,295
Comprehensive (loss) income attributable to:
Molycorp stockholders									-601,806	-371,401	-482,121
Noncontrolling interests									-18,000	-2,546	5,826
Comprehensive loss									($619,806)	($373,947)	($476,295)
Basic:
Continuing operations (in dollars per share)									($2.70)	($2.17)	($4.58)
Discontinued operations (in dollars per share)									$0	($0.04)	($0.02)
Basic (in dollars per share)	($1.43)	($0.47)	($0.37)	($0.40)	($0.95)	($0.43)	($0.44)	($0.27)	($2.70)	($2.21)	($4.60)
Diluted:
Continuing operations (in dollars per share)									($2.70)	($2.17)	($4.58)
Discontinued operations (in dollars per share)									$0	($0.04)	($0.02)
Diluted (in dollars per share)	($1.43)	($0.47)	($0.37)	($0.40)	($0.95)	($0.43)	($0.44)	($0.27)	($2.70)	($2.21)	($4.60)

Consolidated_Statements_of_Sto

Consolidated Statements of Stockholders' Equity (USD $)	Total	Molymet	Total Molycorp Stockholders' Equity	Total Molycorp Stockholders' Equity	Common Stock	Common Stock	Series A Mandatory Convertible Preferred Stock	Additional Paid-In Capital	Additional Paid-In Capital	Accumulated other comprehensive income	Accumulated deficit	Noncontrolling interests	Convertible Preferred Stock	Convertible Preferred Stock	Convertible Preferred Stock	6.00% Convertible Notes, net of discount, due September 2017	6.00% Convertible Notes, net of discount, due September 2017	6.00% Convertible Notes, net of discount, due September 2017	6.00% Convertible Notes, net of discount, due September 2017	6.00% Convertible Notes, net of discount, due September 2017	6.00% Convertible Notes, net of discount, due September 2017	6.00% Convertible Notes, net of discount, due September 2017	5.50% Convertible Notes, net of discount, due February 2018	5.50% Convertible Notes, net of discount, due February 2018	5.50% Convertible Notes, net of discount, due February 2018	5.50% Convertible Notes, net of discount, due February 2018	5.50% Convertible Notes, net of discount, due February 2018	5.50% Convertible Notes, net of discount, due February 2018	5.50% Convertible Notes, net of discount, due February 2018	Convertible Debt Securities	Convertible Debt Securities	Convertible Debt Securities	Convertible Debt Securities
	USD ($)	USD ($)	USD ($)	Molymet	USD ($)	Molymet	USD ($)	USD ($)	Molymet	USD ($)	USD ($)	USD ($)	Common Stock	Series A Mandatory Convertible Preferred Stock	Additional Paid-In Capital	USD ($)	Total Molycorp Stockholders' Equity	Common Stock	Additional Paid-In Capital	Convertible Debt	Convertible Debt	Convertible Debt	USD ($)	Total Molycorp Stockholders' Equity	Common Stock	Additional Paid-In Capital	Convertible Debt	Convertible Debt	Convertible Debt	USD ($)	Total Molycorp Stockholders' Equity	Common Stock	Additional Paid-In Capital
				USD ($)		USD ($)			USD ($)				USD ($)	USD ($)	USD ($)		USD ($)	USD ($)	USD ($)	USD ($)	Total Molycorp Stockholders' Equity	Additional Paid-In Capital		USD ($)	USD ($)	USD ($)	USD ($)	Total Molycorp Stockholders' Equity	Additional Paid-In Capital		USD ($)		USD ($)
																					USD ($)	USD ($)						USD ($)	USD ($)
Balance at the beginning of period at Dec. 31, 2011	$845,230,000		$845,230,000		$84,000		$2,000	$838,547,000		($8,481,000)	$15,078,000	$0
Balance at the beginning of the period (in shares) at Dec. 31, 2011					83,896,043		2,070,000
Increase (Decrease) in Stockholders' Equity
Stock-based compensation	3,434,000		3,434,000		0			3,434,000
Stock-based compensation (in shares)					3,740
Issuance of shares (Note 16)		390,093,000		390,093,000		12,000			390,081,000
Issuance of shares (in shares)						12,500,000
Issuance of shares for interest in Molycorp Canada (Note 16)	334,887,000		284,144,000		14,000			284,130,000				50,743,000
Issuance of shares for interest in Molycorp Canada (Note 16) (in shares)					13,885,622
Issuance of shares for acquisition of exploration rights (Note 8)	8,000,000		8,000,000		1,000			7,999,000
Issuance of shares for acquisition of exploration rights (in shares)					788,410
Components of convertible notes (Note 14)																				68,695,000	68,695,000	68,695,000
Deferred taxes on component of convertible debt	-27,106,000		-27,106,000					-27,106,000
Issuance of shares for conversion of Debentures																														4,527,000	4,527,000		4,527,000
Issuance of shares for conversion of Debentures (in shares)																																99,723
Issuance of Primary Shares (Note 16)	132,130,000		132,130,000		14,000			132,116,000
Issuance of Primary Shares (Note 16) (in shares)					13,800,000
Issuance of Borrowed Shares (Note 16)	25,000		25,000		14,000			11,000
Issuance of Borrowed Shares (Note 16) (in shares)					13,800,000
Net (loss) income	-475,343,000		-481,169,000								-481,169,000	5,826,000
Preferred dividends	-11,385,000		-11,385,000					-11,385,000
Distribution to noncontrolling interests	-5,977,000											-5,977,000
Acquisition of noncontrolling interest (Note 11)	-15,000,000		380,000					380,000				-15,380,000
Other comprehensive loss	-952,000		-952,000							-952,000
Balance at the end of the period at Dec. 31, 2012	1,251,258,000		1,216,046,000		139,000		2,000	1,691,429,000		-9,433,000	-466,091,000	35,212,000
Balance at the end of the period (in shares) at Dec. 31, 2012					138,773,538		2,070,000
Increase (Decrease) in Stockholders' Equity
Stock-based compensation	5,392,000		5,392,000					5,392,000
Stock-based compensation (in shares)					43,803
Issuance of shares (Note 16)	247,567,000		247,567,000		52,000			247,515,000
Issuance of shares (in shares)					51,750,000
Components of convertible notes (Note 14)																											21,815,000	21,815,000	21,815,000
Deferred taxes on component of convertible debt	-8,508,000		-8,508,000					-8,508,000
Issuance of shares for conversion of Debentures																														18,000	18,000		18,000
Issuance of shares for conversion of Debentures (in shares)																																2,471
Issuance of Primary Shares (Note 16)	248,172,000		248,172,000		43,000			248,129,000
Issuance of Primary Shares (Note 16) (in shares)					43,125,000
Issuance of Borrowed Shares (Note 16)	7,000		7,000		7,000
Issuance of Borrowed Shares (Note 16) (in shares)					6,666,666
Conversion of Exchangeable Shares					18,616
Net (loss) income	-376,929,000		-374,383,000								-374,383,000	-2,546,000
Preferred dividends	-11,385,000		-11,385,000					-11,385,000
Distribution to noncontrolling interests	-4,546,000											-4,546,000
Other comprehensive loss	2,982,000		2,982,000							2,982,000
Other	1,219,000											1,219,000
Balance at the end of the period at Dec. 31, 2013	1,377,062,000		1,347,723,000		241,000		2,000	2,194,405,000		-6,451,000	-840,474,000	29,339,000
Balance at the end of the period (in shares) at Dec. 31, 2013					240,380,094		2,070,000
Increase (Decrease) in Stockholders' Equity
Stock-based compensation	4,647,000		4,647,000		0			4,647,000
Stock-based compensation (in shares)					229,664
Components of convertible notes (Note 14)																						68,695							21,815
Issuance of shares for conversion of Debentures													4,000	-2,000	-2,000															12,000	12,000		12,000
Issuance of shares for conversion of Debentures (in shares)													4,140,000	-2,070,000				10,698,113							4,358,490
Conversion of Exchangeable Shares					21,836
Share-lending arrangements (Note 16)	15,062,000		15,062,000					15,062,000
Issuance of Warrants (Note 16)	23,164,000		23,164,000					23,164,000
Exchange of Convertible Notes (Note 14)																8,100,000	8,100,000	10,000	8,090,000				3,527,000	3,527,000	5,000	3,522,000
Net (loss) income	-622,934,000		-604,934,000								-604,934,000	-18,000,000
Preferred dividends	-2,846,000		-2,846,000					-2,846,000
Distribution to noncontrolling interests	-4,222,000											-4,222,000
Other comprehensive loss	3,128,000		3,128,000							3,128,000
Other	-397,000		-576,000					-576,000				179,000
Balance at the end of the period at Dec. 31, 2014	$804,303,000		$797,007,000		$260,000		$0	$2,245,478,000		($3,323,000)	($1,445,408,000)	$7,296,000
Balance at the end of the period (in shares) at Dec. 31, 2014					259,831,422		0

Consolidated_Statement_of_Stoc

Consolidated Statement of Stockholders' Equity (Parenthetical) (Convertible Debt)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Aug. 22, 2012	Jan. 30, 2013
6.00% Convertible Notes, net of discount, due September 2017
Interest rate	6.00%	6.00%	6.00%	6.00%
5.50% Convertible Notes, net of discount, due February 2018
Interest rate	5.50%	5.50%			5.50%

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:
Net loss	($622,934)	($376,929)	($475,343)
Adjustments to reconcile net loss to net cash from operating activities:
Depreciation, amortization and accretion	123,661	105,764	52,808
Deferred income tax benefit	-38,996	-68,290	-23,563
Inventory write-downs	84,414	100,346	83,039
Release of inventory step-up value	993	3,068	24,729
Impairment of goodwill and other long-lived assets	231,650	120,898	301,755
Impairment of investments	12,000	9,411	0
Stock-based compensation	5,261	5,392	3,434
Equity in results of affiliates	26,763	9,169	3,490
Gain on extinguishment of convertible notes, net	-19,719	0	0
PIK interest	3,851	0	0
Change in fair value of embedded derivative	3,879	0	0
Amortization of issuance costs	7,444	0	0
Impairment of other receivables	3,292	0	0
Other operating activities	5,021	1,539	-104
Net change in operating assets and liabilities (Note 22)	-48,784	-64,719	-59,880
Net cash used in operating activities	-222,204	-154,351	-89,635
Cash flows from investing activities:
Cash paid in connection with acquisitions, net of cash acquired	0	0	-591,011
Investment in joint ventures	-703	-3,423	-33,044
Dividends received from equity investment	2,014	0	0
Capital expenditures	-86,158	-379,312	-791,469
Acquisition of exploration rights	0	0	-8,167
Recovery from insurance claims	12,900	0	0
Other investing activities	-984	-5,477	-762
Net cash used in investing activities	-70,963	-377,258	-1,422,929
Cash flows from financing activities:
Issuance of shares to Molymet	0	0	390,093
Repayments of debt	-7,825	-26,823	-228,708
Net proceeds from sale of common stock	0	495,717	132,130
Issuance of Convertible Notes		165,600	395,712
Issuance of 10% Senior Secured Notes	250,000		635,373
Payments of preferred dividends	-2,846	-11,385	-11,385
Dividends paid to noncontrolling interests	-4,222	-4,546	-5,977
Proceeds from debt	0	0	14,699
Debt issuance costs	-15,260	0	0
Proceeds from the 2014 Financings (Note 14)	250,000	0	0
Partial repayment of convertible notes	-27,495	0	0
Other financing activities	0	-1,297	-1,554
Net cash provided by financing activities	192,352	617,266	1,320,383
Effect of exchange rate changes on cash	-1,817	870	1,116
Net change in cash and cash equivalents	-102,632	86,527	-191,065
Cash and cash equivalents at beginning of the period	314,317	227,790	418,855
Cash and cash equivalents at end of period	211,685	314,317	227,790
Convertible Debt
Adjustments to reconcile net loss to net cash from operating activities:
Gain on extinguishment of convertible notes, net	2,000
5.50% Convertible Notes, net of discount, due February 2018 | Convertible Debt
Cash flows from financing activities:
Issuance of Convertible Notes	0	165,600	0
10% Senior Secured Notes, net of discount, due June 2020 | Senior Notes
Cash flows from financing activities:
Issuance of 10% Senior Secured Notes	0	0	635,373
6.00% Convertible Notes, net of discount, due September 2017 | Convertible Debt
Cash flows from financing activities:
Issuance of Convertible Notes	$0	$0	$395,712

Consolidated_Statements_of_Cas1

Consolidated Statements of Cash Flows (Parenthetical)	Dec. 31, 2014	Dec. 31, 2013	Jan. 30, 2013	25-May-12	Dec. 31, 2012	Aug. 22, 2012
5.50% Convertible Notes, net of discount, due February 2018 | Convertible Debt
Interest rate	5.50%	5.50%	5.50%
10% Senior Secured Notes, net of discount, due June 2020 | Senior Notes
Interest rate	10.00%	10.00%		10.00%
6.00% Convertible Notes, net of discount, due September 2017 | Convertible Debt
Interest rate	6.00%	6.00%			6.00%	6.00%

Company_Background

Company Background	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Company Background	Company Background
	We are a leading rare earths producer that operates a vertically integrated, global supply chain that combines a world-class rare earths resource with manufacturing facilities on three continents that can produce a wide variety of custom engineered, advanced rare earth materials from rare earth elements. Our vertically integrated business allows us to operate multiple product supply chains, serve as a supplier of advanced rare earths and rare metal materials, and provide price visibility to customers worldwide.
	Rare earth products are critical inputs in hundreds of existing and emerging applications. A few examples of these include the following: clean energy technologies, such as hybrid and electric vehicles, energy-saving motors, pumps and compressors used in a wide variety of high-efficiency appliances and other durable goods, and wind power turbines; multiple high-tech uses, including mobile devices, fiber optics, lasers, and hard disk drives; critical defense applications, such as guidance and control systems and global positioning systems; and advanced water treatment technology for use in industrial, municipal, and recreational applications. Global demand for REEs is projected by industry analysts to steadily increase both due to continuing growth in existing applications and increased innovation and development of new end uses. We have made significant investments, and expect to continue to invest, in developing technologically advanced applications and proprietary applications for individual REEs.

Going_Concern

Going Concern	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Going Concern	Going Concern
	As a result of continuing softness in the prices for our products, as well as inconsistent or depressed demand for certain of our products and the delayed ramp-up of operations at our Mountain Pass facility, we have incurred, and continue to incur, operating losses. While certain of our business units currently generate positive cash flow from operations, we have not yet achieved break-even cash flow from operations (excluding interest) on a consolidated basis as we continue the ramp-up and optimize production at our Mountain Pass facility.
	As of December 31, 2014, the total principal balance of our outstanding debt is approximately $1.7 billion, including approximately $206.5 million of our 3.25% Convertible Notes that matures on June 15, 2016. Based on our current cash forecast, we may not have sufficient funds available to repay those convertible notes at maturity, in part because the delayed draw proceeds under the 2014 Financings would not be available in the event we do not achieve certain earnings and production targets specified in the 2014 Financings. Additionally, the agreements governing the 2014 Financings contain springing maturity obligations if we do not repay, or provide for the repayment of, certain of our 3.25% Convertible Notes by April 2016. Certain of our debt obligations contain covenants that are subject to interpretation. Although we do not believe we are in breach of any such covenants as at December 31, 2014, if a creditor under any such debt obligations decides to declare a breach of any such covenant, then such creditor could exercise its rights under the applicable debt obligations, which will trigger cross-defaults in other debt obligations. Such actions by creditors could require repayment of our debt before maturity, and we cannot assure you that we will be able to meet such repayment obligations. See more information on our convertible notes and other debt obligations at Note 14.
	In addition, on December 30, 2014, we received notice that we are not in compliance with the continued listing standards of the New York Stock Exchange ("NYSE") because the current trading price for our common stock is below the minimum listing requirements. We are taking actions to meet the compliance standards for continued listing on the NYSE, and are considering seeking approval from our stockholders for a reverse stock split as an alternative means of regaining compliance with the minimum share price requirement. However, we cannot guarantee that we will be able to meet the necessary requirements for continued listing, and, therefore, we cannot guarantee that our common stock will remain listed for trading on the NYSE. If we fail to meet the necessary requirements for our common stock to remain listed on the NYSE or other similar markets, then we will be obligated to offer to repurchase all of our outstanding convertible notes at a price equal to 100% of the aggregate principal amount plus accrued and unpaid interest. Our failure to make such an offer or repurchase any tendered convertible notes will result in an event of default under the indentures governing our convertible notes. Any such event of default will trigger a cross-default on our other debt obligations, including the 2014 Financings. Our inability to cure any such defaults, including the prepayment of our debt obligations, would have a material adverse effect on our financial position and results of operations.
	Capital expenditures for our Mountain Pass facility have decreased significantly and are expected to total approximately $45 million in 2015 and $65 million in 2016. Additionally, we expect to spend approximately $15 million to $20 million on maintenance and expansion capital expenditures across all other operating segments in 2015. Our annual cash interest payments on all debt (excluding capital leases), including unused commitment fees, currently total approximately $124 million. This amount excludes other associated fees and expenses that may become payable by us under our credit agreements. The amount of our cash requirements continues to be dependent on (i) the accuracy of our cost estimates for capital expenditures, (ii) our ability to operate and maintain our Mountain Pass facility and our other operations within our current estimates, (iii) our ability to ramp-up run rates at our Mountain Pass facility pursuant to our expectations without further delays, and to achieve lower cash costs of production as a result of further optimization of operations at our Mountain Pass facility, (iv) stable or improved market conditions, (v) our ability to sell our production of rare earths to external customers and our downstream facilities (including our ability to sell our Cerium through market acceptance of SorbX® or otherwise), (vi) our ability to repatriate cash generated from our global operations, and (vii) the absence of payments on current and future contingent liabilities. If these assumptions prove inaccurate, our estimates could prove incorrect and we will need additional financing in 2015.
	Our cash balances of $211.7 million as of December 31, 2014 represent our primary source of liquidity to fund our capital expenditures, debt service and net operating cash requirements. As part of our plan to achieve positive cash flows from operations, we have implemented initiatives to reduce our operating and administrative costs and we will continue to pursue other cost efficiencies.
	In August 2014, we and certain of our subsidiaries entered into a commitment letter with Oaktree Capital Management, L.P. (collectively with certain of its affiliates and funds under its management, "Oaktree") pursuant to which Oaktree agreed to provide to us and certain of our subsidiaries up to approximately $400.0 million in secured financing through credit facilities and the sale and leaseback of certain equipment at our Mountain Pass facility (the "2014 Financings") for corporate, operating and capital expenditure purposes. On September 11, 2014, we executed agreements governing the 2014 Financings and received initial gross proceeds totaling $250.0 million from Oaktree, with the remaining $149.8 million available to be drawn until April 30, 2016, $134.8 million of which is available only if we achieve certain financial and operational performance targets. Additionally, availability of the other $15.0 million may be limited by certain outstanding balances under our foreign subsidiary credit facilities.
	We regularly evaluate opportunities to reduce our debt and/or related interest costs. In November 2014, we exchanged $11.0 million of the aggregate principal amount of our 5.50% Convertible Notes, and $27.0 million of the aggregate principal amount of our 6.00% Convertible Notes for a total of approximately 15,056,603 shares of our common stock, plus payments in cash of accrued but unpaid interest. See Note 14 for more information on this exchange. Additionally, we may from time to time seek to repurchase other outstanding debt securities with cash and/or exchanges for common stock or securities convertible into common stock or other debt securities.
	In December 2014, our Board of Directors approved the engagement of an independent investment bank and advisory firm to advise us in pursuing various financing alternatives to secure a more sustainable capital structure. While we are evaluating a number of alternatives, we may seek to convert a significant portion of our outstanding debt to equity, including the exchange of debt for shares of our common stock. In addition, we may seek to reduce our cash interest cost and/or extend debt maturity dates by negotiating the exchange of outstanding debt for new debt with modified terms. Although we have been successful in raising funds to date, there can be no assurance that adequate or sufficient funding will be available in the future, or available under terms acceptable to us.
	These circumstances indicate the existence of a material uncertainty that casts substantial doubt as to our ability to meet our business plan and our obligations as they come due and, accordingly, the appropriateness of the use of the accounting principles applicable to a going concern. The accompanying consolidated financial statements have been prepared on a going concern basis that assumes we will be able to continue to realize our assets and discharge our liabilities in the normal course of business, and do not reflect the adjustments to the carrying amount of assets and liabilities that would be necessary if we were unable to obtain adequate financing or restructure our debt. If we are unable to execute our business plan and restructuring our debt, we may not be able to continue as a going concern. The auditor's report is unqualified in respect of this matter.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies
	Basis of Presentation
	The accompanying consolidated financial statements, which are prepared in accordance with GAAP, include our accounts and the accounts of our majority-owned subsidiaries where we exert control. Investments in which we do not have control, and are not considered to be the primary beneficiary of a variable interest entity, but where we exercise significant influence over the operating and financial policies of the investee, are accounted for using the equity method of accounting. All other investments are accounted for at cost. Intercompany balances and transactions have been eliminated in consolidation.
	Certain comparative figures have been reclassified to conform to the presentation adopted in the current year.
	Use of Estimates
	The preparation of the consolidated financial statements, in accordance with GAAP, requires us 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. We base our estimates on historical experience and on various other assumptions that we believe to be reasonable under the circumstances. Actual results may differ significantly from these estimates under different assumptions and conditions. Significant estimates we made in the accompanying financial statements include our ability to collect 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, and the adequacy of the asset retirement obligation.
	Revenues and Costs of Sales
	Revenues are recognized when persuasive evidence of an arrangement exists, the risks and rewards of ownership have been transferred to the customer, which is generally when title passes, the selling price is fixed or determinable, and collection is reasonably assured. Title generally passes to the customer upon shipment of product from our facilities. Certain contracts with customers contain provisions whereby title passes upon loading the product at the shipping port. Prices are generally set at the time of, or prior to, shipment. Transportation and distribution costs are incurred only on sales for which we are responsible for delivering the product.
	Costs of sales include costs of production and write downs of inventory to market value. Primary production costs include labor, raw materials, depreciation, supplies, maintenance costs and plant overhead.
	Cash and Cash Equivalents
	Cash and cash equivalents consist of cash and liquid investments with an original maturity of three months or less. Because of the short maturity of these investments, the carrying amounts approximate their fair values.
	Trade Accounts Receivable
	Trade accounts receivable are recorded at the invoiced amount and do not bear interest. We review the need for an allowance for doubtful accounts quarterly based on historical experience with each customer and the specifics of each arrangement. At December 31, 2014 and 2013, our allowance for doubtful accounts was $2.6 million.
	Inventory
	Inventory consists of stockpiles of crushed ore, bastnasite concentrate, raw materials, work in process, finished goods and materials and supplies. Inventory cost is determined using the lower of weighted average cost or estimated net realizable market value, and includes all expenses directly attributable to the manufacturing process as well as production overheads based on normal operating capacity. We evaluate the carrying amount of inventory each quarter giving consideration to slow-moving items, obsolescence, excessive levels, and other factors and recognizes related write-downs as necessary. Write-downs of inventory to estimated market value are charged to costs of sales. Inventory expected to be used and sold beyond a twelve-month period is classified as a non-current asset in the consolidated balance sheets.
	Property, Plant and Equipment
	Property, plant and equipment obtained in business acquisitions are recorded at their estimated fair value as of the acquisition date. Expenditures for new property, plant and equipment, and improvements that extend the useful life or functionality of the asset are recorded at their cost of acquisition or construction. Depreciation on property, plant and equipment is provided using the straight-line method over their estimated useful lives. Maintenance costs are expensed as incurred.
	Construction in progress includes costs directly attributable to the construction or development of long-term tangible assets. These costs may include: labor and employee benefits associated with the construction of the asset; site preparation; permitting; engineering; installation and assembly; procurement; insurance; legal; commissioning; and interest on borrowings to finance the construction of the asset. Depreciation is not recorded on the related assets until they are placed in service or ready for their intended use.
	Gains or losses arising on the disposal of property, plant and equipment are determined as the difference between the proceeds from disposal and the carrying amount of the asset, and are included in other income (expense) in the consolidated statements of operations and comprehensive loss.
	Mineral Properties and Development Costs
	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, all of which are capitalized. We deplete mineral properties using the units of production method over estimated proven and probable reserves. Depletion expense is an inventoriable cost.
	Intangible Assets
	Intangible assets consist primarily of customer relationships, patents and other intellectual properties, Chinese land use rights and both indefinite-lived and finite-lived trade names. Finite-lived intangible assets are amortized on a straight-line basis over the estimated useful lives, which range from 2 to 16 years for customer relationships, patents and trade name, and 50 years for Chinese land use rights.
	Recoverability of Long-Lived Depreciable/Amortizable Assets
	Long-lived assets such as property, plant, and equipment, mineral properties and intangible assets that are depreciated or amortized, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset or asset group may not be recoverable. An impairment is considered to exist if the total undiscounted future cash flows expected from the use of the asset or asset group are less than its carrying amount. An impairment loss, if any, is recorded for the excess of the asset's or asset group's carrying amount over its fair value, as determined by a valuation technique appropriate to the given circumstances.
	Recoverability of Goodwill
	We assign goodwill arising from acquired companies to the reporting units that are expected to benefit from the acquisition. On an annual basis or in interim periods when circumstances require, we test the recoverability of our goodwill utilizing a two-step impairment analysis. Under this analysis, we initially compare the fair value of each identified reporting unit with the reporting unit's carrying amount. Our reporting units are determined either at the operating segment level or a component one level below the operating segment that constitutes a business for which the operating segment's management generally reviews production and financial results. To the extent that a reporting unit's fair value is less than its carrying amount, we perform an additional step to determine the implied fair value of the reporting unit's goodwill. The implied fair value of goodwill is calculated by first allocating the reporting unit's fair value to its assets and liabilities, excluding goodwill, and then comparing the excess of the reporting unit's fair value to the carrying amount of goodwill. To the extent that the carrying amount of goodwill exceeds its implied fair value, we would recognize an impairment loss. The valuation methodology utilized to determine the fair value of our reporting units is based on a discounted cash flow model, or income approach, in which expected future net cash flows, excluding any financing costs or dividends, are discounted using an appropriate discount rate. The income approach is dependent upon a number of significant management estimates about future performance including expected sales volumes, sales prices, production costs, income taxes, capital expenditures, working capital changes, foreign exchange rates and the after-tax weighted average cost of capital. Changes in any of these assumptions could materially impact the estimated fair value of our reporting units. Discount factors are determined individually for each reporting unit to reflect its respective risk profile as assessed by us.
	Investments
	Investments in non-marketable equity securities of entities in which we have the ability to exercise significant influence over the entity's operating and financial policies are accounted for by the equity method. We recognize our proportionate share of the entity’s income or loss each period with such amounts included in "Equity in income (loss) of affiliates" in the consolidated statements of operations and comprehensive income (loss). Equity method investments are reviewed periodically for other-than-temporary decline in value. Investments in non-marketable equity securities of entities for which we do not have the ability to exercise significant influence over the entity’s operations and financial policies are accounted for at cost, and are subject to periodic other-than-temporary impairment assessments.
	Business Combinations
	We account for all business combinations using the acquisition method of accounting. Under this method, assets and liabilities, including any noncontrolling interests, are recognized at fair value at the date of acquisition. The excess of the purchase price over the fair value of assets acquired, net of liabilities assumed, and noncontrolling interests is recognized as goodwill. Certain adjustments to the assessed fair values of the assets, liabilities, or noncontrolling interests made subsequent to the acquisition date, but within the measurement period, which is up to one year, are recorded as adjustments to goodwill. Any adjustments subsequent to the measurement period are recorded in income. Any cost or equity method interest that we hold in the acquired company prior to the acquisition is remeasured to fair value at acquisition with a resulting gain or loss recognized in income for the difference between fair value and the existing book value. Results of operations of the acquired entity are included in our results from the date of the acquisition. We expense all costs as incurred related to an acquisition under “Corporate development” in the consolidated statement of operations and comprehensive income (loss).
	Asset Retirement Obligation
	We account for reclamation costs, along with other costs related to the closure of our Mountain Pass facility, in accordance with ASC 410-20, Asset Retirement Obligations, which requires us to recognize an ARO at its estimated fair value in the period in which the obligation is incurred. Events that trigger the recognition of an ARO include land disturbances and construction of a property for which there is a legal obligation to restore the land and the property to their original state. The liability is initially measured at fair value using a discounted cash flow model, and is subsequently adjusted for accretion expense and changes in the amount or timing of the estimated cash flows. A corresponding asset retirement cost is capitalized as part of the carrying amount of the related long-lived assets and is amortized over the assets’ remaining useful lives.
	Income Taxes
	We account for income taxes in accordance with Accounting Standard Codification 740, Income Taxes, which requires that deferred tax assets and liabilities be recognized for the tax effect of temporary differences between the financial statement and tax basis of recorded assets and liabilities at enacted statutory tax rates. This guidance also requires that deferred tax assets be reduced by a valuation allowance if it is more likely than not that some portion or all of the deferred tax assets will not be realized based on both our historical and anticipated earnings levels. We review our deferred tax assets each reporting period to determine if adjustments to the valuation allowance are necessary.
	We record our deferred tax assets and liabilities using enacted tax rates expected to apply to taxable income for the period in which the deferred tax assets or liabilities are expected to be realized. The statutory income tax rates that are applied to the current and deferred income tax calculations differ by the jurisdictions in which we conduct business. Changes in such income tax rates and apportionment laws may result in changes in our deferred income tax assets, liabilities and related expense in the period of enactment.
	Foreign Currency
	The functional currency of the majority of our operations is the U.S. dollar. Assets and liabilities recorded in functional currencies other than the functional currency are translated at the spot rate in effect at the applicable reporting date; revenues and expenses in foreign currencies are translated at actual exchange rates for significant transactions or at the average exchange rates in effect during the applicable period. The resulting unrealized cumulative translation adjustment is recorded as a component of "Accumulated other comprehensive income (loss)" in the consolidated balance sheets. The effect of exchange rates on cash balances held in foreign currencies are separately reported in our consolidated statements of cash flows.
	Transactions denominated in currencies other than the applicable functional currency are recorded based on exchange rates at the time such transactions occur. Changes in exchange rates associated with monetary amounts recorded in our consolidated balance sheets related to these non-functional currency transactions result in transaction gains and losses that are reflected in "Foreign exchange gains (losses), net" in the consolidated statements of operations and comprehensive income (loss).
	Correction of Functional Currency
	As part of our acquisition of Molycorp Silmet on April 1, 2011, we determined that its functional currency was the Euro. During the fourth quarter of 2014, we reconsidered a number of economic indicators that apply to the operations of Molycorp Silmet and concluded that the U.S. dollar should have been the functional currency that most faithfully represents the economic effects of its underlying transactions. Because this misstatement, both individually and in the aggregate, was not material to any of our prior years’ financial statements, and the impact of correcting it was not material to the full-year 2014 financial statements, we adjusted the cumulative effect of changing the functional currency of Molycorp Silmet in the fourth quarter of 2014. The out-of-period adjustment had the following impact on the consolidated balance sheet and the consolidated statement of operations and comprehensive loss in 2014:
	Increase to balance sheet captions:	(In thousands)
	Other current assets	$	91
	Inventory	2,339
	Property, plant and equipment	7,742
	Other non-current assets	275
	Other current liabilities	8
	Accumulated other comprehensive income	14,281
	Increase (decrease) to statements of operations and comprehensive loss captions:
	Revenues	$	270
	Costs of sales	5,745
	Foreign exchange gain	1,633
	Net loss	3,842
	Foreign currency translation adjustments	(14,281		)
	Comprehensive loss	(10,439		)
	Comprehensive Income (Loss)
	We present comprehensive income (loss) in two separate, but consecutive statements. In addition to "Net income (loss)", "Comprehensive income (loss)" includes foreign currency translation adjustments and actuarial gains and losses associated with the defined benefit pension benefits and post-retirement benefits for the employees of one of Molycorp Canada’s former manufacturing facilities.
	Earnings (Loss) per Share
	Basic earnings (loss) per share is computed by dividing our net income (loss) attributable to our stockholders, reduced by cumulative undeclared and paid dividends on any outstanding preferred stock, by the weighted average number of shares of common stock outstanding during the period.
	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, are deemed options for purposes of computing diluted earnings per share. 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. 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.
	Research and Development
	Research and development costs, which consist primarily of salaries, outside labor, material and equipment, are expensed as incurred.
	Recent Accounting Pronouncements
	In August 2014, the FASB issued ASU 2014-15, Presentation of Financial Statements - Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern. This update provides guidance about management’s responsibilities in evaluating an entity’s going concern uncertainties, and about the timing and content of related footnote disclosures. Under this amended guidance, an entity’s management should evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the entity’s ability to continue as a going concern within one year after the date that the financial statements are issued (or within one year after the date that the financial statements are available to be issued when applicable). Management’s evaluation should be based on relevant conditions and events that are known and reasonably knowable at the date that the financial statements are issued (or at the date that the financial statements are available to be issued when applicable). Substantial doubt about an entity’s ability to continue as a going concern exists when relevant conditions and events, considered in the aggregate, indicate that it is probable that the entity will be unable to meet its obligations as they become due within one year after the date that the financial statements are issued (or available to be issued). The term probable is used consistently with its use in Topic 450, Contingencies. When management identifies conditions or events that raise substantial doubt about an entity’s ability to continue as a going concern, management should consider whether its plans that are intended to mitigate those relevant conditions or events will alleviate the substantial doubt. The mitigating effect of management’s plans should be considered only to the extent that (1) it is probable that the plans will be effectively implemented and, if so, (2) it is probable that the plans will mitigate the conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern. If conditions or events raise substantial doubt about an entity’s ability to continue as a going concern, but the substantial doubt is alleviated as a result of consideration of management’s plans, the entity should disclose information that enables users of the financial statements to understand all of the following (or refer to similar information disclosed elsewhere in the footnotes):
a. Principal conditions or events that raised substantial doubt about the entity’s ability to continue as a going concern (before consideration of management’s plans);
b. Management’s evaluation of the significance of those conditions or events in relation to the entity’s ability to meet its obligations; and
c. Management’s plans that alleviated substantial doubt about the entity’s ability to continue as a going concern.
If conditions or events raise substantial doubt about an entity’s ability to continue as a going concern, and substantial doubt is not alleviated after consideration of management’s plans, an entity should include a statement in the footnotes indicating that there is substantial doubt about the entity’s ability to continue as a going concern within one year after the date that the financial statements are issued (or available to be issued). Additionally, the entity should disclose information that enables users of the financial statements to understand all of the following:
a. Principal conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern;
b. Management’s evaluation of the significance of those conditions or events in relation to the entity’s ability to meet its obligations; and
c. Management’s plans that are intended to mitigate the conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern.
This update is effective for the annual period ending after December 15, 2016, and for annual periods and interim periods thereafter. Early application is permitted.
In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606). The core principle of this new guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To achieve that core principle, an entity should apply the following steps:
Step 1: Identify the contract(s) with a customer.
Step 2: Identify the performance obligations in the contract.
Step 3: Determine the transaction price.
Step 4: Allocate the transaction price to the performance obligations in the contract.
Step 5: Recognize revenue when (or as) the entity satisfies a performance obligation.
The new guidance also specifies the accounting for some costs to obtain or fulfill a contract with a customer. An entity will be required to disclose sufficient qualitative and quantitative information to enable users of financial statements to understand the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. For calendar-year public entities, the new guidance is effective starting in 2017, and interim periods within that year. Early adoption is not permitted. An entity should apply the amendments in this update using one of the following two methods:
1	Retrospectively to each prior reporting period presented.
2	Retrospectively with the cumulative effect of initially applying this update recognized at the date of initial application. If an entity elects this transition method, it also should provide the additional disclosures in reporting periods that include the date of initial application of:
i.	The amount by which each financial statement line item is affected in the current reporting period by the application of this update as compared to the guidance that was in effect before the change.
ii.	An explanation of the reasons for significant changes.
We intend to adopt ASU 2014-09 in our financial statements for the annual period beginning on January 1, 2017. The extent of the impact of adoption of the standard has not yet been determined.

Segment_Information

Segment Information	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Segment Information	Segment Information
	Our operations are organized into four reportable segments, each reflecting a unique combination of product lines and technologies: Resources, Chemicals and Oxides, Magnetic Materials and Alloys, and Rare Metals.
	The Resources segment includes our operations at the Mountain Pass facility, where we perform rare earth minerals extraction to produce LREC; separated rare earth oxides, including Lanthanum, Cerium, and Neodymium-Praseodymium; heavy rare earth concentrates, which include Samarium, Europium, Gadolinium, Terbium, Dysprosium, and others; and a line of proprietary rare earth-based water treatment products, including SorbX® and PhosFIX™.
	The Chemicals and Oxides segment includes the following productions: rare earths from our Molycorp Silmet AS, or Molycorp Silmet, facility in Sillamäe, Estonia; separated heavy rare earth oxides and other custom engineered materials from our majority-owned Jiangyin Jia Hua Advanced Material Resources Co., Ltd. facility, or Molycorp Jiangyin, in Jiangyin, Jiangsu Province, China; and rare earths, salts of REEs, zirconium-based engineered materials, and mixed rare earth/zirconium oxides from our majority-owned Zibo Jia Hua Advanced Material Resources Co., Ltd. facility, or Molycorp Zibo, in Zibo, Shandong Province, China. At our Chemicals and Oxides segment, we develop and sell rare-earth based oxides for all the major emission catalysts manufacturers. Several factors are driving an increasing demand for emission catalysts, including the following: the accelerating shift of vehicle production to the BRIC countries (Brazil, India, Russia and China); the continuous development of new emission catalytic solutions; and an overall tightening of environmental regulations around the world. Other applications that utilize rare earths and zirconium-based materials we produce at our Chemicals and Oxides segment include computers, television display panels, optical lenses, mobile phones, electronic chips, and many others.
	The Magnetic Materials and Alloys segment includes the production of Neo Powders™ through our wholly-owned manufacturing facilities in Tianjin, China, and Korat, Thailand, under the Molycorp Magnequench brand. This operating segment also includes manufacturing of Neodymium and Samarium magnet alloys and other specialty alloy products and rare earth metals at our Molycorp Metals and Alloys, Inc., or MMA, facility in Tolleson, Arizona. Neo Powders™ are used in the production of high performance, bonded NdFeB permanent magnets, which are found in micro motors, precision motors, sensors, and other applications requiring high levels of magnetic strength, flexibility, small size, reduced weight, and energy efficient performance.
	The Rare Metals segment produces, reclaims, refines, and markets high value niche metals and their compounds that include Gallium, Indium, Rhenium, Tantalum, and Niobium. Operations in this segment are distributed in several locations: Quapaw, Oklahoma; Blanding, Utah; Peterborough, Ontario, Canada; Sagard, Germany; Hyeongok Industrial Zone in South Korea; and Sillamäe, Estonia. Applications from products made in this segment include wireless technologies, LED, flat panel display, turbine, solar, catalyst, steel additive, electronics applications, and others. The growing adoption of LED applications, which require the use of Gallium trichloride, is allowing the Rare Metals segment to benefit from the decline in certain rare earth phosphor applications.
	The accounting polices used in the preparation of our reportable segment financial information are the same as those used in the preparation of our consolidated financial statements. The primary metric we use to measure the financial performance of each reportable segment is OIBDA (Operating income before depreciation, amortization and accretion), which provides a better indication of the base-line performance of our core business operations.
	Year ended December 31, 2014	Resources			Chemicals and Oxides			Magnetic Materials and Alloys			Rare Metals			Corporate and other(a)			Eliminations(b)			Total Molycorp, Inc.
		(In thousands)
	Revenues:
	External	$	14,097		$	159,365		$	222,795		$	79,355					$	—		$	475,612
	Inter-segment	34,093			22,056			7,591			—						(63,740		)	—
	Total revenues	$	48,190		$	181,421		$	230,386		$	79,355					$	(63,740	)	$	475,612
	OIBDA	(146,157		)	(202,588		)	52,966			(442		)
	Depreciation, amortization and accretion	(78,739		)	(17,401		)	(16,956		)	(10,343		)
	Operating (loss) income (c)	$	(224,896	)	$	(219,989	)	$	36,010		$	(10,785	)	$	(33,195	)	$	1,984		$	(450,871	)
	Other expense																			(5,092		)
	Foreign exchange loss, net																			(3,146		)
	Interest expense, net of capitalized interest																			(167,375		)
	Gain on extinguishment of convertible notes, net																			19,719
	Impairment of investment at cost																			$	(12,000	)
	Loss before income taxes and equity earnings																			$	(618,765	)
	Total assets at December 31, 2014	$	1,593,105		$	248,040		$	618,314		$	105,826		$	1,385,265		$	(1,374,564	)	$	2,575,986
	Capital expenditures (d)	$	49,364		$	3,907		$	2,120		$	2,063		$	—		$	—		$	57,454
	Year ended December 31, 2013	Resources			Chemicals and Oxides			Magnetic Materials and Alloys			Rare Metals			Corporate and other (a)			Eliminations(b)			Total Molycorp, Inc.
		(In thousands)
	Revenues:
	External	$	33,621		$	181,815		$	252,713		$	86,241					$	—		$	554,390
	Inter-segment	26,040			37,256			—			—						(63,296		)	—
	Total revenues	$	59,661		$	219,071		$	252,713		$	86,241					$	(63,296	)	$	554,390
	OIBDA	(177,384		)	(65,135		)	50,899			(12,456		)
	Depreciation, amortization and accretion	(46,318		)	(22,754		)	(27,812		)	(8,652		)
	Operating (loss) income (c)	$	(223,702	)	$	(87,889	)	$	23,087		$	(21,108	)	$	(46,126	)	$	(953	)	$	(356,691	)
	Other expense																			1,886
	Foreign exchange loss, net																			(376		)
	Interest expense, net of capitalized interest																			(67,684		)
	Impairment of investment at cost																			(9,411		)
	Loss before income taxes and equity earnings																			$	(432,276	)
	Total assets at December 31, 2013	$	1,791,421		$	485,642		$	590,516		$	82,538		$	1,547,267		$	(1,490,582	)	$	3,006,802
	Capital expenditures (d)	$	231,027		$	6,961		$	3,700		$	7,549		$	250		$	—		$	249,487
	Year ended December 31, 2012	Resources			Chemicals and Oxides			Magnetic Materials and Alloys			Rare Metals (e)			Corporate and other(a)			Eliminations(b)			Total Molycorp, Inc.
		(In thousands)
	Revenues:
	External	$	88,870		$	181,849		$	179,335		$	77,642					$	—		$	527,696
	Inter-segment	7,256			25,717			—			—						(32,973		)	—
	Total revenues	$	96,126		$	207,566		$	179,335		$	77,642					$	(32,973	)	$	527,696
	OIBDA	(56,229		)	(177,949		)	(105,806		)	(12,834		)
	Depreciation, amortization and accretion	(13,991		)	(13,110		)	(19,737		)	(5,837		)
	Operating loss (c)	$	(70,220	)	$	(191,059	)	$	(125,543	)	$	(18,671	)	$	(85,459	)	$	24,803		$	(466,149	)
	Other expense																			(38,798		)
	Foreign exchange gain, net																			2,872
	Interest expense, net of capitalized interest																			(22,116		)
	Loss before income taxes and equity earnings																			$	(524,191	)
	Capital expenditures (d)	$	814,054		$	10,910		$	5,614		$	10,750		$	1,733		$	—		$	843,061
	(a)	Includes business development costs, personnel costs, stock-based compensation, accounting and legal fees, occupancy expense, information technology costs and interest expense.
	(b)	Consists of inter-segment sales and gross profits eliminations as well as eliminations of lower of cost or market adjustments related to inter-segment inventory.
	(c)	Includes impairment of goodwill and other long-lived assets in some segments. See Notes 7 and 9 below for details.
	(d)	On an accrual basis excluding capitalized interest. Interest was no longer capitalized in 2014.
	(e)	Excludes operating results from the Napanee facility, which is treated as a discontinued operation for comparative purposes.
	The geographic distribution of our revenues based on our customers' locations for the years ended December 31, 2014, 2013 and 2012, was as follows:
		Years Ended December 31,
		2014			2013			2012
		(In thousands)
	Asia:
China	$	162,980		$	199,021		$	118,086
Japan	100,468			99,952			160,942
Thailand	19,585			17,129			7,674
Hong Kong	—			8,815			4,793
South Korea	14,451			12,418			3,828
Singapore	150			54			212
North America	89,769			92,066			103,555
Europe	86,285			113,549			117,907
Other	1,924			11,386			10,699
Total	$	475,612		$	554,390		$	527,696
Our property, plant and equipment, net carrying amounts by geographic location at December 31, 2014 and 2013 were as follows:
	At December 31,
	2014			2013
	(In thousands)
North America	$	1,582,291		$	1,627,892
Europe	68,212			73,674
China	49,930			53,131
Thailand	5,457			6,213
Other Asia	2,080			1,913
Other	—			51
Total	$	1,707,970		$	1,762,874

Inventory

Inventory	12 Months Ended
	Dec. 31, 2014
Inventory Disclosure [Abstract]
Inventory	Inventory
	At December 31, 2014 and 2013, our inventory consisted of the following:
		December 31,
		2014		2013
		(In thousands)
	Current:
	Concentrate stockpiles	$	—	$	24
	Raw materials	47,796		42,627
	Work in process	24,901		41,962
	Finished goods	67,795		65,662
	Materials and supplies	28,831		21,508
	Total current	$	169,323	$	171,783
	Long-term:
	Concentrate stockpiles	$	—	$	4
	Raw materials	25,127		25,325
	Total long-term	$	25,127	$	25,329
	The following table presents charges to costs of sales related to our assessment of normal production levels and write-downs of inventory:
		December 31,
		2014		2013		2012
		(In thousands)
	Abnormal production costs expensed in the period (a)	$	93,917	$	88,070	$	11,982
	Write-down to the lower of cost or market (b)	84,414		100,346		80,939
	Write-downs of stockpile inventory (c)	—		—		2,100
	Total	$	178,331	$	188,416	$	95,021
	(a)	Relates to production costs that would have been inventoriable had we been operating at normal production levels. In all periods presented, the majority of these production costs related to the Resources segment.
	(b)	Attributable to the decline in rare earths prices and low inventory turnover.
	(c)	Adjustments of the estimated REO content in the stockpile at the Resources segment.

Deposits

Deposits	12 Months Ended
	Dec. 31, 2014
Deposits [Abstract]
Deposits	Deposits
	We had $31.1 million and $26.0 million in deposits reported as non-current assets at December 31, 2014 and 2013, respectively, which consisted of the following:
		December 31,
		2014		2013
		(In thousands)
	Escrow arrangement with Kern River Gas Transmission Company ("Kern River")	$	20,612	$	20,612
	Construction insurance program	2,710		1,504
	Collateral placed against the surety bonds issued to California state and regional agencies for the closure and reclamation obligations at the Mountain Pass facility, and other deposits	7,756		3,881
	Total	$	31,078	$	25,997

Property_Plant_and_Equipment_n

Property, Plant and Equipment, net	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment, net	Property, Plant and Equipment, net
	We capitalized expenditures of $57.5 million, $320.7 million and $902.3 million for the years ended December 31, 2014, 2013 and 2012, respectively. In each year, the majority of these expenditures related to the expansion and modernization efforts, and certain other capital projects at our Mountain Pass facility (Resources segment). In 2013 and 2012, these amounts included capitalized interest of $71.2 million and $59.3 million, respectively, which we added to "Construction in progress" until the asset was complete and ready for its intended use. Subsequently, capitalized interest was allocated to the pertinent asset class, such as "Land improvements", "Building and improvements" or "Plant and equipment", and amortized over the estimated useful life of the asset. Starting in 2014, we no longer capitalized interest because the construction of our Mountain Pass facility was substantially complete at the beginning of the year.
	Depreciation expense for the years ended December 31, 2014, 2013 and 2012 was $97.8 million, $60.3 million and $20.9 million, respectively. These amounts include amortization of assets under capital leases totaling $2.8 million, $2.3 million and $0.9 million in each respective year. At December 31, 2014 and 2013, our property, plant and equipment consisted of the following:
		December 31,
		2014			2013
		(In thousands)
	Land	$	13,121		$	12,822
	Land improvements (15 to 30 years)	305,119			327,029
	Buildings and improvements (4 to 40 years)	811,418			418,510
	Plant and equipment (2 to 15 years)	623,453			288,603
	Vehicles (7 years)	2,884			2,986
	Computer software (5 years)	12,268			12,424
	Furniture and fixtures (5 years)	1,039			1,044
	Construction in progress (a)	80,699			755,107
	Natural gas delivery facility under capital lease (10 years)	15,658			15,658
	Mining equipment under capital lease (7 years)	10,982			7,370
	Mineral properties (Note 8)	23,669			23,999
	Property, plant and equipment at cost	1,900,310			1,865,552
	Less accumulated depreciation	(192,340		)	(102,678		)
	Property, plant and equipment, net	$	1,707,970		$	1,762,874
	(a)	Primarily related to expenditures at the Molycorp Mountain Pass facility.
	In order to write-off certain equipment no longer in use or certain capital projects that we placed on hold indefinitely, we recognized impairment charges of $14.4 million, $16.3 million and $5.9 million in 2014, 2013 and 2012, respectively, which are included in "Impairment of goodwill and other long-lived assets" in the consolidated statement of operations and comprehensive loss. Of these charges, $13.6 million, $14.2 million and $3.8 million, in each respective year, related to assets that were held and used at our Mountain Pass facility. In 2014, we received insurance proceeds of approximately $12.9 million to settle disputes with certain of our engineering and construction service providers related to claims for defective workmanship associated with the construction of our Mountain Pass facility. These insurance proceeds were recorded against the assets affected by defects.

Mineral_Properties

Mineral Properties	12 Months Ended
	Dec. 31, 2014
Extractive Industries [Abstract]
Mineral Properties	Mineral Properties
	Mineral properties include capitalized acquisition costs, drilling costs, and the cost of other development work associated with our Mountain Pass facility. We deplete our mineral properties using the units of production method over estimated proven and probable reserves. Refer to Part I, Item 2. "Properties" for more information on our mineral reserves and some statistics pertaining to our mining-through-flotation processes for the three-year period ended December 31, 2014.
	During the fourth quarter of 2012, we had capitalized certain exploration rights in property, plant and equipment for total of $16.2 million, which we paid with the issuance of 788,410 shares of our common stock at $10.147 per share, and $8.2 million in cash. At December 31, 2013, we determined that the mineral deposits underlying these exploration rights could not be economically extracted and, as a result, we recognized an impairment charge of $16.2 million in "Impairment of goodwill and other long-lived assets" in the consolidated statement of operations and comprehensive loss.

Goodwill_and_Other_Intangible_

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets
	Goodwill
	For purposes of testing the recoverability of our goodwill, we identified reporting units that substantially mirror our reportable segments, except for our Molycorp Silmet facility and our Buss & Buss facility. Our Molycorp Silmet facility, which is included in the Chemicals and Oxides segment in relation to the production of rare earths, and in the Rare Metals segment in relation to the manufacturing of tantalum and niobium, is treated as a separate reporting unit because it has an immaterial goodwill balance that would not be practical to allocate to its manufacturing components under different reportable segments. Our Buss & Buss facility is reported under our Rare Metals segment and is treated as a separate reporting unit for purposes of this test. Our Resources segment has no goodwill.
	As part of the recoverability of goodwill test we performed at December 31, 2014, we recognized an impairment charge of $125.2 million to write-off the carrying amount of our Chemicals and Oxides segment's goodwill. This impairment was driven by our revised cash flows projections reflecting the declining market demand for lighting phosphor products, and the continuing softness in the prices of products sold at our Chemicals and Oxides segment. Also as of December 31, 2014, we recognized an impairment charge of approximately $0.7 million at our Rare Metals segment to write-off the remaining goodwill associated with the rare metals production at our Molycorp Silmet facility. Finally, we determined that the fair value of our Magnetic Materials and Alloys segment exceeded its carrying amount by approximately 10% as of December 31, 2014.
	As of December 31, 2013, we concluded that the fair value of our Chemicals and Oxides segment and our Molycorp Silmet facility exceeded their respective carrying amounts; the fair value of our Magnetic Materials and Alloys segment approximated its carrying amount; our Rare Metals segment, excluding the Buss & Buss facility, had a fair value in excess of its carrying amount, but the Buss & Buss facility's fair value was less than its carrying amount. As a result, we performed an additional step to determine the implied fair value of the Buss & Buss facility's goodwill and recognized an impairment charge of approximately $11.0 million in the Rare Metals segment to account for the excess of such implied goodwill over its carrying amount. The main factors leading to this impairment charge in 2013 included reduced cash flows projections for the Buss & Buss business combined with an increase in the reporting unit's working capital, which stemmed, primarily, from the revaluation of its inventory.
	At December 31, 2012, we concluded that our Molycorp Silmet facility's fair value exceeded its carrying amount; however, for the other reporting units that included goodwill, the estimated fair value did not exceed their respective carrying amounts. As a result, we completed step two of the impairment test and determined that the certain goodwill was impaired for our Chemicals and Oxides, Magnetic Materials and Alloys, and Rare Metals segments. We initially recorded a goodwill impairment charge of approximately $258.3 million, which was primarily associated with the reporting units created as a result of the Molycorp Canada acquisition. However, in connection with the final allocation of the consideration transferred as a result of the Molycorp Canada acquisition, which was completed in the second quarter of 2013, we increased the initial carrying amount of goodwill by $31.6 million, but recognized an immediate impairment charge of $31.6 million that completely offset the incremental goodwill. This additional goodwill impairment was recognized retroactively in the fourth quarter of 2012. Circumstances that negatively affected our estimate of fair value of our reporting units in 2012 included: the depressed pricing environment for certain rare earths and rare metals; delays in the development of products by our customers that utilize rare earths and rare metals; and delays in ramping up our Mountain Pass facility, which impaired our ability to enter into longer-term contracts, and generate the anticipated synergies expected from the Molycorp Canada acquisition.
	During the recoverability of goodwill test we performed at December 31, 2014, we determined that the goodwill impairment charge we recognized in 2012 was not properly allocated to the noncontrolling interests of our Chemicals and Oxides segment. Given that this allocation was not material to any of our prior years’ financial statements, and the impact of correcting it was not material to the full-year 2014 financial statements, we recorded an out-of-period adjustment of approximately $10.3 million that increased the loss attributable to noncontrolling interest in the statement of operations and comprehensive loss for the year ended December 31, 2014, with an offset to the statement of stockholders' equity.
	Changes in the carrying amount of goodwill by reportable segment during the years ended December 31, 2014, 2013 and 2012, were as follows:
		Chemicals and Oxides				Magnetic Materials and Alloys				Rare Metals				Total
		(In thousands)
	31-Dec-11	$	728			$	1,977			$	727			$	3,432
	Goodwill acquired	285,633				213,525				27,046				526,204
	Impairment	(161,132		)		(112,694		)		(16,068		)		(289,894		)
	31-Dec-12	125,229				102,808				11,705				239,742
	Impairment	—				—				(10,992		)		(10,992		)
	31-Dec-13	125,229				102,808				713				228,750
	Impairment	(125,229		)		—				(713		)		(125,942		)
	31-Dec-14	$	—			$	102,808			$	—			$	102,808
	Other Intangible Assets
	At December 31, 2014 and 2013, our intangible assets, other than goodwill, consisted of the following:
		Customer relationships			Rare earths quotas			Patents			Trade names			Land use rights			Other		Total
	Gross carrying amount	(In thousands)
	31-Dec-13	$	344,580		$	—		$	152		$	15,586		$	3,568		$	4,420	$	368,306
	Additions	—			—			—			—			—			37		37
	Foreign currency translation adjustment	177			—			—			—			—			—		177
	Impairment	(121,057		)	—			—			—			(368		)	—		(121,425		)
	31-Dec-14	$	223,700		$	—		$	152		$	15,586		$	3,200		$	4,457	$	247,095
	Accumulated Amortization
	31-Dec-13	$	35,980		$	—		$	27		$	343		$	227		$	862	$	37,439
	Amortization	23,019			—			125			66			77			617		23,904
	Impairment	(30,119		)	—			—			—			—			—		(30,119		)
	31-Dec-14	28,880			—			152			409			304			1,479		31,224
	Net book value	$	194,820		$	—		$	—		$	15,177		$	2,896		$	2,978	$	215,871
		Customer relationships			Rare earths quotas			Patents			Trade names			Land use rights			Other		Total
	Gross carrying amount	(In thousands)
	31-Dec-12	$	344,774		$	78,300		$	33,252		$	15,586		$	3,568		$	4,420	$	479,900
	Additions	48			—			—			—			—			—		48
	Foreign currency translation adjustment	(242		)	—			—			—			—			—		(242		)
	Impairment	—			(78,300		)	(33,100		)	—			—			—		(111,400		)
	31-Dec-13	$	344,580		$	—		$	152		$	15,586		$	3,568		$	4,420	$	368,306
	Accumulated Amortization
	31-Dec-12	$	14,095		$	4,035		$	9,365		$	1,152		$	66		$	249	$	28,962
	Amortization	22,145			7,018			13,554			65			161			613		43,556
	Adjustments	(260		)	—			—			(874		)	—			—		(1,134		)
	Impairment	—			(11,053		)	(22,892		)	—			—			—		(33,945		)
	31-Dec-13	35,980			—			27			343			227			862		37,439
	Net book value	$	308,600		$	—		$	125		$	15,243		$	3,341		$	3,558	$	330,867
	As of December 31, 2014, as a result of lower long-term growth prospects due to a shift in technology affecting certain market, we recognized an impairment charge of approximately $90.9 million related to certain customer relationships reported under our Chemicals and Oxides and Rare Metals segments. The majority of the intangible assets impaired were associated with the Molycorp Canada acquisition. We updated our fair value estimate of these customer relationships based on the income approach using certain unobservable inputs, including a customer attrition rate of approximately 13%.
	In December 2013, we determined there was no longer value associated with our Chinese rare earths export quotas because the Chinese government in 2013 had turned to other means for controlling its domestic rare earth industry and, therefore, our Molycorp Zibo and Molycorp Jiangyin facilities in the Chemicals and Oxides segment would no longer be able to benefit from the related export premiums. As a result, we recognized an impairment charge of $67.2 million for the rare earths quotas in 2013 under "Impairment of goodwill and other long-lived assets" in the consolidated statement of operations and comprehensive loss.
	Based on a discounted cash flow analysis using updated margin projections on products manufactured by our Magnetic Materials and Alloys segment using a patent that expired in 2014, we recorded impairment charges of $10.2 million and $6.0 million in 2013 and 2012, respectively, which are included under "Impairment of goodwill and other long-lived assets" in the consolidated statement of operations and comprehensive loss for these prior periods. Amortization expense on our other intangible assets in 2012 was $28.6 million.
	Our trade names balance at December 31, 2014 includes $14.8 million of intangible assets that are not subject to amortization. These assets, which we acquired in 2012, are our only indefinite-lived intangible assets. Amortization expense on all other intangible assets for the next five years and thereafter is expected to be as follows:
		(In thousands)
	2015	$	16,441
	2016	16,441
	2017	16,441
	2018	16,277
	2019	16,277
	Thereafter	119,194

Investments

Investments	12 Months Ended
	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Investments	Investments
	The following table provides a reconciliation of the carrying amount of our investments at December 31, 2014 and 2013:
		Boulder Wind Power, Inc.			IMJ			Keli			Ingal Stade			Other investments				Total
		(In thousands)
	31-Dec-12	$	20,000		$	25,193		$	11,000		$	5,015		$	2,828			$	64,036
	Additions	—			3,419			—			—			—				3,419
	Equity loss	n/a			(6,529		)	(2,600		)	(40		)	—				(9,169		)
	Impairment	(8,000		)	—			—			—			(1,411		)	(a)	(9,411		)
	31-Dec-13	12,000			22,083			8,400			4,975			1,417				48,875
	Adjustment to investments classification	—			51			(1,240		)	(38		)	1,227				—
	Additions	—			—			—			—			703				703
	Dividends	—			—			(2,014		)	—			—				(2,014		)
	Equity (loss) income	n/a			(6,541		)	(635		)	(51		)	158				(7,069		)
	Impairment	(12,000		)	(14,808		)	—			(4,886		)	—				(31,694		)
	31-Dec-14	$	—		$	785		$	4,511		$	—		$	3,505			$	8,801
	(a) The impairment charge in 2013 relates to the equity interest in Atlantic Metals & Alloys, LLC.
	Boulder Wind Power, Inc.
	In 2011, we invested $20.0 million into Boulder Wind Power, Inc. ("BWP") Series B convertible preferred stock that we accounted for at cost. BWP is a company engaged in the development of permanent magnet generators and power conversion technology. At December 31, 2013, due to certain delays in the commercialization of BWP's technology, we reassessed the fair value of this investment and determined to write it down by $8.0 million. In the third quarter of 2014, the Board of Directors of BWP approved a plan to wind-down BWP's day-to-day operations and pursue potential sales opportunities for its portfolio of intellectual properties. Due to the current status of BWP's operations and uncertainty around the timing and amount of any future value from the investment in BWP, in the third quarter of 2014 we recognized an impairment charge of $12.0 million to write-off the remaining investment balance in BWP in impairment of investments at cost in the consolidated statement of operations and comprehensive loss.
	Intermetallics Japan Joint Venture ("IMJ")
	In November 2011, we, Daido Steel Co., Ltd. (“Daido”) and Mitsubishi Corporation (“Mitsubishi”) entered into an agreement for the purpose of manufacturing sintered NdFeB permanent rare earth magnets. The capital contribution ratio of IMJ was 30.0% by us, 35.5% by Daido and 34.5% by Mitsubishi; our total contribution to IMJ was approximately $31.0 million. IMJ was created to further develop and commercialize a technology that would allow the production of high performance sintered NdFeB permanent magnets, with a competitive cost structure based on REE market prices that existed in 2011. Because of the spike in REE price in 2011, and the associated uncertainty that spike created in the supply chain of rare earth products, end-users' specifications for sintered NdFeB permanent magnets have changed over the last couple of years and, as a result, IMJ's technology would require further investments to meet current customers' demand. Given our focus on the optimization and production ramp up at our Mountain Pass facility to serve the needs of our existing customer base, in December 2014, we considered an offer from Daido to buy-out Mitsubishi's and our proportional share of the investment in IMJ for approximately $1.0 million each. As of December 31, 2014, negotiations with Daido were ongoing. As a result of our decision to consider the buy-out offer from Daido, we recognized a charge of approximately $14.8 million in "Equity loss of affiliates" in the consolidated statement of operations and comprehensive loss to write-off the majority of our investment in IMJ as of December 31, 2014. The results of operations of this joint venture are reported under our Resources segment based on the equity method of accounting.
	Ganzhou Keli Rare Earth New Material Co., Ltd. (“Keli”)
	We acquired a 25% equity interest in Keli for $12.2 million on June 11, 2012. Keli is a Chinese business that converts REO into metals for use in our Neo Powders™.
	Ingal Stade GmbH (“Ingal Stade”)
	On June 11, 2012, as part of the Molycorp Canada acquisition, we acquired a 50% ownership interest in Ingal Stade for $4.9 million, a German joint venture involved in the extraction of gallium metal ("GaM") from alumina smelter bayer liquor with purity level of 5N (99.999%) or higher. In December 2014, we decided to cease purchasing GaM from Ingal Stade because the joint venture can no longer provide this metal at a competitive price. Since the purchase of GaM at a competitive price was the main value proposition of our investment in Ingal Stade, as of December 31, 2014 we recognized a charge of $4.9 million in "Equity loss of affiliates" in the consolidated statement of operations and comprehensive loss to write-off the balance of our investment in Ingal Stade. In addition, we wrote-off the balance of a loan receivable from Ingal Stade of $3.3 million, which we recognized in "Other expense" in the consolidated statement of operations and comprehensive loss after our investment in the equity of Ingal Stade was reduced to zero. The results of operations of this joint venture were reported under our Rare Metals segment based on the equity method of accounting.

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
Acquisitions	Acquisitions
	Molycorp Canada
	On June 11, 2012, we 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., our wholly-owned Canadian subsidiary, which are exchangeable for shares of our 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 our common stock or Exchangeable Shares, all subject to the proration mechanics set forth in the Arrangement Agreement.
	The consideration we 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 24. Additionally, 13,545,426 shares of our common stock and 507,203 Exchangeable Shares were issued and collectively valued at $284.1 million based on the closing price of our 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, we further adjusted the preliminary values assigned to certain assets and liabilities of Molycorp Canada in order to reflect additional information we 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 we recognized in the fourth quarter of 2012 increased by $31.6 million to $287.9 million. The other 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 our consolidated statements of operations and comprehensive loss or cash flows in any period, those statements were not retrospectively adjusted.
	The following table summarizes the purchase consideration as well as the estimated fair value of the assets acquired and liabilities assumed in the Molycorp Canada acquisition:
		Preliminary Allocation of Consideration Transferred as of December 31, 2012			Measurement Period Adjustments			Final Allocation of Consideration 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
	Intangible assets	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 Molycorp Canada acquisition 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.
	The following unaudited pro forma financial information provides what our consolidated revenues, net income (loss) and basic earnings per share would have been had the acquisition closed on January 1, 2012:
	(In thousands, except per share amounts)	Revenues				Net income (loss)				Net income (loss)			EPS Basic
										attributable to Molycorp
	Unaudited pro forma January 1, 2012 to December 31, 2012 (combined entity)	$	863,728			$	(463,716	)		$	(473,249	)	$	(4.53	)
	The unaudited pro forma revenues, earnings and earnings per share amounts have been adjusted to: a) eliminate the effect of sales and costs that occurred previous to the business combination between us and Molycorp Canada; b) reflect the 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 our federal, state and international statutory tax rates based on the applicable tax jurisdictions; and d) the estimated increase in interest expense associated with the issuance of our Senior Notes (as defined below) the proceeds from which were used to finance a portion of the purchase consideration. The unaudited pro forma earnings of the combined entity for the year ended December 31, 2012 were also adjusted to exclude $115.2 million of non-recurring costs. The weighted average number of shares outstanding utilized in the basic income (loss) per share calculations have been adjusted to reflect the common shares we issued to Molibdenos y Metales S.A. ("Molymet"), the proceeds from which were used to finance a portion of the purchase consideration.
	For the year ended December 31, 2012, we recognized approximately $62.0 million of transaction costs related to the Molycorp Canada acquisition in our consolidated statement of operations and comprehensive loss as follows:
		(In thousands)
	Corporate development:
	Legal, accounting and advisory fees	$	16,498
	Other expenses:
	Contingent forward contract loss	$	37,589
	Interest expense:
	Bridge loan fee	$	7,937
	Increase of Equity Interest in Molycorp Jiangyin
	During the fourth quarter of 2012, we acquired an additional 5% of our majority-owned Molycorp Jiangyin joint venture, bringing our equity interest to 95%. The investment in this joint venture was originally part of the Molycorp Canada acquisition. The purchase price for the additional equity interest in Molycorp Jiangyin was $15.0 million, of which $5.4 million we paid in cash on the date of closing and the remaining $9.6 million, plus accrued interest of $0.2 million, which was paid in cash at end of 2013.

Accrued_Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2014
Payables and Accruals [Abstract]
Accrued Expenses	Accrued Expenses
	Accrued expenses at December 31, 2014 and 2013 consisted of the following:
		December 31,
		2014		2013
		(In thousands)
	Defined contribution plan	$	613	$	1,921
	Professional fees	1,955		135
	Accrued payroll and related benefits	7,010		5,739
	Sales and use tax	2,339		3,354
	Bonus accrual	5,109		4,449
	Interest payable	18,300		18,158
	Advance from customer	130		600
	Withholding taxes	376		2,563
	Amount payable to noncontrolling interest	2,929		—
	Other accrued expenses	13,205		11,582
	Total accrued expenses	$	51,966	$	48,501

Asset_Retirement_Obligation

Asset Retirement Obligation	12 Months Ended
	Dec. 31, 2014
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligation	Asset Retirement Obligation
	Under applicable environmental laws and regulations, we are subject to reclamation and remediation obligations resulting from the mining operations at our Mountain Pass facility. The following table presents the activity of our ARO for the years ended December 31, 2014 and 2013:
		December 31,
		2014			2013
		(In thousands)
	Balance at beginning of period	$	17,583		$	22,125
	Obligations settled	(1,549		)	(3,849		)
	Accretion expense	1,153			1,328
	Revisions in estimated cash flows	—			(3,793		)
	Loss on settlement	932			1,772
	Balance at end of period	$	18,119		$	17,583
	The balances above for the years ended December 31, 2014 and 2013 include a short-term portion of $0.3 million and $0.6 million, respectively, which were recorded under "Other current liabilities" in the consolidated balance sheets. Depreciation expense associated with the ARO was $0.6 million, $2.5 million and $2.0 million in 2014, 2013 and 2012, respectively. The balances presented above represent our estimated future discounted cash flows required to satisfy the obligations currently known to us. The total estimated future undiscounted cash flows required to satisfy our ARO was $33.1 million as of December 31, 2014. The discount rates we used to recognize the ARO in the balance sheets range from 5% to 10%, depending on the timing of when the obligations arose or were updated.
	In the fourth quarter of 2013, we changed the timing of certain reclamation efforts in connection with the updated closure plan at our Mountain Pass facility from 2035 to 2042 and, as a result, we reduced our ARO by $3.8 million in 2013. The combination of the updated closure plan and the ARO reduction in 2013 explains the lower depreciation expense we recognized in 2014 for the ARO. In order to expand the mine pit to an area partially occupied by our legacy flotation plant, we substantially demolished that plant in 2013, and incurred costs in excess of our original reclamation estimate that led to a large portion of the settlement loss of $1.8 million we recognized in 2013. The demolition of the legacy flotation plant was completed in the first quarter of 2014.
	We are required to provide the applicable governmental agencies with financial assurances relating to our closure and reclamation obligations. At December 31, 2014, we had financial assurance requirements of $28.8 million, which were satisfied with surety bonds placed with the California state and regional agencies.

Debt_and_Capital_Lease_Obligat

Debt and Capital Lease Obligations	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Debt and Capital Lease Obligations	Debt and Capital Lease Obligations
	The following table provides a summary of the current and non-current portions of our debt and capital lease obligations at December 31, 2014 and 2013:
		December 31,
		2014								2013
		Current				Non-Current				Current				Non-Current
		(In thousands)
	Bank loans due February 2015 - June 2017	$	9,326			$	91			$	14,128			$	2,699
	3.25% Convertible Notes, net of discount, due June 2016	—				193,549				—				207,028
	6.00% Convertible Notes, net of discount, due September 2017	—				335,969				—				346,708
	5.00% Debentures, net of discount, due December 2017	—				2,075				—				2,493
	5.50% Convertible Notes, net of discount, due February 2018	—				143,581				—				148,198
	12.00% Term Loans, due September 2019	—				98,812				—				—
	12.00% Equipment Financing, due September 2019	—				127,594				—				—
	10% Senior Secured Notes, net of discount, due June 2020	—				638,899				—				637,435
	Total debt	$	9,326			$	1,540,570			$	14,128			$	1,344,561
	Capital lease obligations	3,234				19,211				2,234				19,355
	Total debt and capital lease obligations	$	12,560			$	1,559,781			$	16,362			$	1,363,916
	A reconciliation of the principal amount to the net carrying amount for each of our Convertible Notes and our 10% Senior Secured Notes at December 31, 2014 and 2013 is as follows:
		3.25% Convertible Notes							6.00% Convertible Notes							5.50% Convertible Notes						10% Senior Notes
		At December 31,
		2014			2013				2014			2013				2014			2013			2014			2013
		(In thousands)
	Principal amount	$	206,505		$	230,000			$	383,000		$	414,000			$	161,500		$	172,500		$	650,000		$	650,000
	Unamortized debt discount	(12,956		)	(22,972		)		(47,031		)	(67,292		)		(17,919		)	(24,302		)	(11,101		)	(12,565		)
	Net carrying amount	$	193,549		$	207,028			$	335,969		$	346,708			$	143,581		$	148,198		$	638,899		$	637,435
	Interest cost incurred on each instrument in the table immediately above was as follows for the years ended December 31, 2014, 2013 and 2012:
		Year Ended December 31,
		2014				2013				2012
		(In thousands)
	3.25% Convertible Notes	$	15,553			$	15,839			$	15,312
	6.00% Convertible Notes	41,070				39,779				17,457
	5.50% Convertible Notes	14,578				13,107				n/a
	10% Senior Notes	66,606				66,323				40,070
	The interest cost listed above is comprised of the coupon interest, the accretion of the underwriting discounts, the accretion of the initial equity component of the convertible notes (3.25% - $36,227; 6.00% - $68,695; and 5.50% - $21,815), and the amortization of the issuance costs.
	Weighted average interest rate on our bank loans was 4.10% and 3.59% at December 31, 2014 and 2013, respectively, and our total amount of unused lines of credit was $20.3 million at December 31, 2014. This amount excludes the portion of the 2014 Financings available to be drawn. Our scheduled minimum debt repayments, excluding capital lease obligations, were as follows at December 31, 2014:
	Debt maturities, excluding capital leases	(In thousands)
	2015	$	9,326
	2016	206,565
	2017	385,106
	2018	161,500
	2019	321,154
	Thereafter	650,000
	Total	$	1,733,651
	As of December 31, 2014, we were in compliance with all applicable covenants related to our indebtedness. However, as disclosed in Note 2, certain financial and operational conditions indicate the existence of a material uncertainty that casts substantial doubt on our ability to meet our obligations as they come due.
	2014 Debt Issuance
	12% Term Loans and 12% Equipment Financing
	On September 11, 2014 (the “closing date”), we received initial gross proceeds totaling $250.0 million from the 2014 Financings with Oaktree, with the remaining $149.8 million available to be drawn until April 30, 2016, $134.8 million of which is available only if we satisfy certain financial and operational conditions. Net proceeds from the 2014 Financings were approximately $207.1 million after the repayment of approximately $23.7 million of principal amount (plus accrued interest) and $4.0 million of principal amount (plus accrued interest) of our 3.25% Convertible Notes and 6.00% Convertible Notes, respectively, owned by Oaktree (“Oaktree Notes Repurchase”), $8.0 million paid to Oaktree as a commitment yield enhancement, and the payment of transaction costs of approximately $7.3 million. As a result of the Oaktree Notes Repurchase, we recognized a loss on extinguishment of $2.0 million in the statements of operations and comprehensive loss for the year ended December 31, 2014.
	The 2014 Financings consist of two term loans and one equipment financing, as follows:
	a.	A term loan facility of $185.0 million (the “Parent Term Loan”), $50.2 million of which was advanced on the closing date and $134.8 million is available to be drawn in the minimum amount of $50.0 million at any time until April 30, 2016, subject to the satisfaction of certain conditions, including (i) consolidated adjusted EBITDA of no less than $20.0 million for each of two consecutive fiscal quarters, and (ii) evidence that production at our Mountain Pass facility is equal to or greater than 4,000 mt for each of two consecutive fiscal quarters, in each case prior to, but including, the fiscal quarter ending on March 31, 2016. Proceeds from the Parent Term Loan have been and will be used for capital expenditures, interest expense and general corporate purposes, including the Oaktree Notes Repurchase and the payment of transaction expenses.
	b.	A term loan facility of $75.0 million (the “Magnequench Term Loan”), $60.0 million of which was advanced on the closing date and $15.0 million of delayed draw term loans to be advanced, subject to the satisfaction of certain conditions, in minimum amounts of $5.0 million after the closing date and until April 30, 2016. Proceeds from the Magnequench Term Loan will be used to satisfy certain intercompany obligations of Magnequench, Inc. and to make certain intercompany loans.
	Interest rates on the Parent Term Loan and the Magnequench Term Loan (collectively, the “Term Loans”) are: (i) from the closing date through June 14, 2016, 7.00% per year payable in cash and 5.00% per year payable in kind (“PIK interest”) and (ii) from June 15, 2016, and thereafter, 12.00% per year payable in cash, unless our 3.25% Convertible Notes have been repaid in full with the proceeds of the sale of our common equity or by the exchange of such convertible notes for our common equity, or any combination thereof (the “2016 Notes Equity Refinancing”), in which case, interest will accrue as indicated in (i) above. The daily average unused amount of the delayed draw Term Loans commitment for the Term Loans is subject to an unused commitment enhancement payment of 1.00% per year.
	The Term Loans mature on September 11, 2019, with springing maturity dates at (i) April 30, 2016, if we have not repaid, escrowed or extended an amount of cash sufficient to repay when due and payable the 3.25% Convertible Notes down to $40.0 million in the aggregate and (ii) March 31, 2017, if we have not repaid or escrowed an amount of cash sufficient to repay when due and payable (a) our 6.00% Convertible Notes down to $80.0 million in the aggregate and (b) our 5.50% Convertible Notes down to $40.0 million in the aggregate.
	We cannot make any voluntary prepayments on the Term Loans prior to the fourth anniversary of the closing date. In addition, any prepayment of the loans and any repayment (or other satisfaction) of the loans after acceleration, but prior to September 11, 2019, will be subject to an early payment premium of (i) 43.8% of the principal amount so prepaid if paid prior to the first anniversary of the closing date, (ii) 33.7% of the principal amount so prepaid if paid on or after the first anniversary of the closing date but prior to the second anniversary of the closing date, (iii) 23.0% of the principal amount so prepaid if paid on or after the second anniversary of the closing date but prior to the third anniversary of the closing date, (iv) 11.5% of the principal amount so prepaid if paid on or after the third anniversary of the closing date but prior to the fourth anniversary of the closing date, and (vi) 3.0% of the principal amount so prepaid if paid on or after the fourth anniversary of the closing date. Any mandatory prepayment of the loans resulting from an asset sale will be subject to an early payment premium of 3.0% of the principal amount so prepaid.
	The springing maturity dates, in combination with the early payment premiums applicable to any prepayment of the loans described above, meet the definition of a derivative that is required to be bifurcated from its host debt instrument. Because this derivative is to be classified as a liability, we recognized a discount on the Term Loans as of the closing date of approximately $1.7 million, in the aggregate, which will be amortized to interest expense over the duration of the Term Loans. See Note 24 for more information on this derivative.
	c.	A Purchase and Sale Agreement pursuant to which we sold certain equipment including, but not limited to, parts of our natural gas powered co-generation power plant, the Chlor-Alkali facility and the water treatment plant (collectively, the “Equipment”), located at our Mountain Pass facility. In exchange for the sale of the Equipment, we received proceeds of $139.8 million that have been and will be used for the development and improvement of the Equipment and other assets at our Mountain Pass facility, and may be used, to the extent permitted under our 10% Senior Notes indenture and the Parent Term Loan, for interest payments and other general corporate purposes.
	Concurrently with entering into the Purchase and Sale Agreement, we and Oaktree entered into an Equipment Lease Agreement, which we refer to as the "Equipment Financing", whereby we leased back all of the Equipment. The Equipment Financing has a five-year term with the following approximate annual rent payments (due quarterly in arrears): $10.1 million in the first year, $10.7 million in the second year, $11.2 million in the third year, $11.8 million in the fourth year and $12.4 million in the fifth year with an additional payment of approximately $179.9 million on the fifth anniversary of the lease commencement date (“Base Rent Payments”); provided, that unless the 2016 Notes Equity Refinancing, as defined above, has occurred by June 15, 2016, the rent will be adjusted to require annual payments of $18.0 million for years two through five and a payment of approximately $147.0 million on the fifth anniversary of the lease commencement date. Base Rent Payments on the Equipment Financing are based on a 7% annual rate applied to the unpaid principal balance plus accrued, but unpaid interest calculated at an annual rate of 5%.
	Due to the existence of several forms of our continuing involvement with the Equipment, we are required to account for the Equipment Financing as a direct financing under GAAP, rather than a sale-leaseback. Additionally, since the rent payments do not cover the total interest expense of the Equipment Financing, we recognize such payments as interest only with no principal reduction of the financing obligation. However, the unpaid interest calculated at an annual rate of 5% increases the financing obligation up to the final payment due on the fifth anniversary of the Equipment Financing, whether or not the 2016 Notes Equity Refinancing occurs.
	In connection with the 2014 Financings, we issued warrants to Oaktree to purchase up to an aggregate of 24,477,359 shares of our common stock. For accounting purposes, a portion of the proceeds from the 2014 Financings was allocated to the warrants, which created a discount on the Term Loans and the Equipment Financing of approximately $28.2 million, in the aggregate. This discount will be recognized as interest expense over the term of the 2014 Financings. See Note 16 and Note 24 for more information on the warrants.
	The following table presents a reconciliation of the principal amount to the net carrying amount of, and interest cost for, the Term Loans and the Equipment Financing at December 31, 2014:
		12.00% Term Loans				12.00% Equipment Financing
		(In thousands)
	Principal amount (a)	$	111,858			$	141,993
	Unamortized debt discount	(13,046		)		(14,399		)
	Net carrying amount	$	98,812			$	127,594
Cash interest	$	6,264			$	2,082
PIK interest	1,691				2,160
Total interest cost	$	7,955			$	4,242
Obligations under the 2014 Financings are guaranteed by us and certain of our subsidiaries (the “Pari Passu Guarantors”) that also guarantee the obligations under our 10% Senior Notes. Our obligations and those of the Pari Passu Guarantors under the 2014 Financings are secured by a pari passu lien on substantially all of our assets and the assets of the Pari Passu Guarantors (the “Pari Passu Collateral”) on an equal and ratable basis with the obligations under the 10% Senior Notes. The maximum principal amount of debt under the 2014 Financings secured by the Pari Passu Collateral shall not exceed $300.0 million in the aggregate at any time or such higher amount permitted by the Pari Passu Indenture. In addition, the obligations under the 2014 Financings are guaranteed by certain of our other subsidiaries (the “First Priority Guarantors”). The obligations of the First Priority Guarantors under the 2014 Financings are secured by a first priority lien on certain equity interests owned by the First Priority Guarantors, including equity interests of certain foreign subsidiaries. In addition, the Magnequench Credit Agreement is secured by a first priority lien on substantially all of the assets of Magnequench, Inc.
2013 Debt Issuance
On January 30, 2013, we issued $150.0 million aggregate principal amount of our 5.50% Convertible Senior Notes due 2018 (the “5.50% Convertible Notes”) in a registered public offering. Certain of our officers, directors and other related parties 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, net proceeds from the issuance of the 5.50% Convertible Notes were $165.6 million.
The 5.50% Convertible Notes are our 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 our common stock, cash, or a combination thereof, at our election. The conversion rate will initially be 138.8889 shares of our common stock per $1,000 principal amount of notes (equivalent to an initial conversion price of approximately $7.20 per share of our 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. We 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 our existing and future secured indebtedness.
We separately account 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 our 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 $21.8 million is included in additional paid-in capital in the consolidated balance sheet and is treated as original issue discount for purposes of accounting for the liability component. Transaction costs related to the issuance of the 5.50% Convertible Notes have been allocated to the liability and equity components in proportion to the allocation of proceeds to the components, and accounted for as debt issuance costs (recognized as interest expense over the life of the 5.50% Convertible Notes using the effective interest method) and equity issuance costs (charged against equity), respectively.
In the fourth quarter of 2014, we exchanged $11.0 million aggregate principal amount our 5.50% Convertible Notes for a total of 4,358,490 shares of our common stock, plus a payment in cash of accrued but unpaid interest. As a result of this exchange, we recognized a gain on debt extinguishment of $6.3 million in the consolidated statement of operations and comprehensive loss for the year ended December 31, 2014, and accounted for the difference of $1.2 million between the consideration transferred to the holder and the fair value of the liability component of our 5.50% Convertible Notes, as a reduction of "Additional Paid-In Capital" in our consolidated statement of stockholders’ equity as of December 31, 2014.
2012 Debt Issuances and Assumed Liabilities
6.00% Convertible Notes
On August 22, 2012, we issued $360.0 million aggregate principal amount of our 6.00% Convertible Senior Notes due 2017 (the “6.00% Convertible Notes”) in a registered public offering. On August 28, 2012, the underwriters of the 6.00% Convertible Notes exercised their option to purchase an additional $54.0 million aggregate principal amount of the 6.00% Convertible Notes. Total net proceeds from the issuance of the 6.00% Convertible Notes were $395.7 million, after deducting the underwriting discounts and commissions. Certain of our directors, officers and other related parties purchased $6.4 million of the aggregate principal amount of the 6.00% Convertible Notes, for which we did not pay any underwriting discounts and commissions.
The 6.00% Convertible Notes are our senior unsecured obligations with interest payable semi-annually in arrears on March 1 and September 1 of each year, commencing on March 1, 2013. The 6.00% Convertible Notes will mature on September 1, 2017, unless earlier repurchased, redeemed or converted in accordance with their terms, and will be convertible at any time prior to the second scheduled trading day immediately preceding the maturity date into shares of common stock, cash, or a combination thereof, at our election. The conversion rate will initially be 83.333 shares of common stock per $1,000 principal amount of 6.00% Convertible Notes (equivalent to an initial conversion price of approximately $12 per share of common stock), subject to customary adjustments. We will have the right to redeem the 6.00% Convertible Notes on or after September 1, 2015 if the last reported sale price of our common stock has been at least 130% of the conversion price then in effect for at least 20 trading days during any 30 consecutive trading day period ending on, and including, the trading day immediately preceding the date on which we provide notice of redemption at a redemption price equal to 100% of the principal amount of the 6.00% Convertible Notes to be redeemed, plus accrued and unpaid interest. The 6.00% Convertible Notes rank equal in right of payment to existing and future liabilities that are not expressly subordinated to the 6.00% Convertible Notes, and rank effectively junior to our existing and future secured indebtedness.
We separately account for the liability and equity components of convertible debt instruments, such as the 6.00% Convertible Notes, that may be settled entirely or partially in cash upon conversion in a manner that reflects our economic interest cost. The additional discount on the liability component is amortized to interest cost over the term of the 6.00% Convertible Notes. The equity component of $68.7 million is included in additional paid-in in the consolidated balance sheet and is treated as original issue discount for purposes of accounting for the liability component. Transaction costs related to the issuance of the 6.00% Convertible Notes have been allocated to the liability and equity components in proportion to the allocation of proceeds to the components, and accounted for as debt issuance costs and equity issuance costs, respectively.
In the fourth quarter of 2014, we exchanged $27.0 million aggregate principal amount our 6.00% Convertible Notes for a total of 10,698,113 shares of our common stock, plus a payment in cash of accrued but unpaid interest. As a result of this exchange, we recognized a gain on debt extinguishment of $15.4 million in the consolidated statement of operations and comprehensive loss for the year ended December 31, 2014, and accounted for the difference of $3.5 million between the consideration transferred to the holder and the fair value of the liability component of our 6.00% Convertible Notes, as a reduction of "Additional Paid-In Capital" in our consolidated statement of stockholders’ equity as of December 31, 2014.
In September 2014, we repaid $4.0 million of our 6.00% Convertible Notes principal amount as part of the 2014 Financings.
5.00% Debentures
As a result of the Molycorp Canada acquisition, we assumed $230.0 million principal amount of subordinated unsecured convertible debentures of the predecessor of Molycorp Canada due December 2017 (the “Debentures”) maturing on December 31, 2017. The Debentures bear interest at 5.00% per annum and are convertible at $13.80 per share of Molycorp Canada's predecessor company. As required under the change of control provisions contained in the original underlying indenture, holders of the Debentures had the option to either require us to repurchase the Debentures at par plus accrued interest, convert the Debentures into common shares of Molycorp Canada's predecessor company, including a number of additional “make-whole” shares, or hold the Debentures to maturity. In August 2012, holders of $9.4 million aggregate principal amount of Debentures elected to convert, while holders of $217.9 million aggregate principal amount of Debentures elected to early redeem their Debentures for cash plus accrued interest. Under the term of the indenture governing the Debentures, as amended at the time of the Molycorp Canada acquisition, the holders of the Debentures that converted received, at their election and in lieu of receiving shares of Molycorp Canada's predecessor company, the same cash and/or share consideration that was paid to Molycorp Canada's former shareholders in connection with the acquisition of Molycorp Canada, subject to the same pro-ration calculation, as if such holders had converted immediately prior to the acquisition. As a result of the conversion in August 2012, a total of $8.0 million, including accrued interest, was paid in cash with the remainder converted into 99,723 shares of our common stock.
10% Senior Notes
On May 25, 2012, we issued $650.0 million aggregate principal amount of senior secured notes due 2020 (the "Senior Notes") in an offering that was exempt from the registration requirements of the Securities Act. Total net proceeds from the issuance of the Senior Notes were $635.4 million after deducting the initial purchasers' discounts. The Senior Notes bear interest at the rate of 10% per year payable on June 1 and December 1 of each year beginning on December 1, 2012. At any time and from time to time prior to June 1, 2016, we may redeem any of the Senior Notes at a price equal to 100% of the principal amount thereof plus an applicable make-whole premium and accrued and unpaid interest. At any time and from time to time from and after June 1, 2016, we may redeem the Senior Notes, in whole or in part, at a redemption price for the Senior Notes plus accrued and unpaid interest, initially at 105% of the principal amount thereof, but gradually declining to 100% of the principal amount thereof. In addition, at any time and from time to time prior to June 1, 2015, we may redeem up to 35% of the aggregate principal amount of the Senior Notes with the net cash proceeds of one or more permitted sales of our capital stock at a redemption price (expressed as a percentage of principal amount) of 110% plus accrued and unpaid interest. Upon the occurrence of a change of control, we will be required to offer to repurchase all of the Senior Notes. The Senior Notes are our senior secured obligations and are guaranteed by certain of our domestic subsidiaries ("Guarantors"). The Senior Notes are secured by first-priority security interest on substantially all of our property and assets, and the property and assets of 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
•	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.
A substantial portion of the net proceeds from the offering of the Senior Notes was used to fund the cash consideration that we paid for Molycorp Canada, with the remainder used for general corporate purposes. We and the Guarantor filed an exchange offer registration statement with the SEC on November 23, 2012, which was declared effective on February 7, 2013.
2011 Debt Issuance
3.25% Convertible Notes
On June 15, 2011, we issued $230.0 million aggregate principal amount (net proceeds of $223.1 million after deducting the initial purchasers’ discounts and commissions) of our 3.25% Convertible Notes due 2016 (the “3.25% Convertible Notes”) in an offering exempt from the registration requirements of the Securities Act. The Notes are our senior unsecured obligations and bear interest at a rate of 3.25% per annum, payable semi-annually in arrears on June 15 and December 15 of each year, commencing on December 15, 2011. The 3.25% Convertible Notes are convertible at any time into shares of our common stock, cash, or a combination thereof, at our election. The initial conversion rate is 14.0056 shares of our common stock per $1,000 principal amount of the 3.25% Convertible Notes (equivalent to an initial conversion price of approximately $71.40 per share of our common stock), subject to customary adjustments. The 3.25% Convertible Notes mature on June 15, 2016, unless repurchased or converted in accordance with their terms. We do not have the right to redeem the 3.25% Convertible Notes prior to maturity.
We separately account for the liability and equity components of convertible debt instruments, such as the 3.25% Convertible Notes, that may be settled entirely or partially in cash upon conversion in a manner that reflects our economic interest cost. The additional discount on the liability component is amortized to interest cost over the term of the 3.25% Convertible Notes. The equity component of $36.2 million is included in additional paid-in capital in the consolidated balance sheet and is treated as original issue discount for purposes of accounting for the liability component. Transaction costs related to the issuance of the 3.25% Convertible Notes have been allocated to the liability and equity components in proportion to the allocation of proceeds to the components, and accounted for as debt issuance costs and equity issuance costs, respectively.
In September 2014, we repaid approximately $23.5 million of our 3.25% Convertible Notes principal amount as part of the 2014 Financings.
Capital Leases
We lease certain mining and other equipment under agreements with various durations that have been determined to be capital leases. Those agreements contain purchase options at the end of the lease term and are generally at market interest rates. At December 31, 2014, total future minimum payments on our capital leases were as follows:
Capital Leases	(In thousands)
2015	$	8,276
2016	8,276
2017	7,159
2018	5,769
2019	5,488
Thereafter	12,706
Total	$	47,674
Imputed interest included in total future minimum lease payments at December 31, 2014	$	22,655

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes
	Our net loss before income taxes and equity earnings for the year ended December 31, 2014 included an impairment charge of $125.9 million related to goodwill, which is not deductible for tax purposes. We had net deferred income tax liabilities of $54.5 million at December 31, 2014 primarily related to the purchase accounting adjustment associated with the Molycorp Canada acquisition. We determined that a valuation allowance of $252.3 million was required at December 31, 2014. Furthermore, primarily due to uncertainty concerning the qualification for a lower tax rate in a foreign jurisdiction, liabilities for uncertain tax positions increased by a net amount of $1.2 million in fiscal 2014.
	For the years ended December 31, 2014, 2013 and 2012 our effective income tax rate was 3.7%, 16.4% and 10.3%, respectively. The 2014 effective income tax rate was impacted primarily by the valuation allowance required in both the U.S. and Canada, and the impairment of goodwill not deductible for tax purposes.
	We had undistributed earnings of certain foreign subsidiaries at December 31, 2014 for which deferred taxes of $10.4 million have been provided. Also, we had undistributed earnings of certain foreign subsidiaries at December 31, 2014, 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 $1.4 million at December 31, 2014.
	Income tax expense consisted of the following for the years ended December 31, 2014, 2013 and 2012:
		Years Ended December 31,
		2014			2013			2012
		(In thousands)
	Current
	Federal	$	—		$	(2,581	)	$	(22,418	)
	Foreign	16,532			(1,018		)	8,994
	State	(130		)	792			(4,197		)
	Total current	16,402			(2,807		)	(17,621		)
	Deferred
	Federal	(8,111		)	(43,479		)	(20,786		)
	Foreign	(29,366		)	(16,517		)	(11,777		)
	State	(1,519		)	(8,140		)	(3,891		)
	Total deferred	(38,996		)	(68,136		)	(36,454		)
	Total tax benefit	$	(22,594	)	$	(70,943	)	$	(54,075	)
	The components of our losses before income taxes and equity earnings, by tax jurisdiction, were as follows for the years ended December 31, 2014, 2013 and 2012:
		Years Ended December 31,
		2014			2013			2012
		(In thousands)
	United States	$	(415,381	)	$	(286,818	)	$	(161,129	)
	Foreign	(203,384		)	(145,458		)	(363,062		)
	Total	$	(618,765	)	$	(432,276	)	$	(524,191	)
	A reconciliation of the statutory federal income tax rate of 35% to our effective income tax rate is as follows for the years ended December 31, 2014, 2013 and 2012:
		Years Ended December 31,
		2014			2013			2012
		(In thousands)
	Federal tax computed at the statutory rate	$	(216,568	)	$	(151,297	)	$	(184,075	)
	State taxes, net of federal benefit	(16,609		)	(10,329		)	(5,970		)
	Change in valuation allowance	148,187			85,881			19,515
	Impairment of goodwill and other long-lived assets	48,250			7,458			103,563
	Changes related to uncertain tax positions	1,220			(5,153		)	(14,176		)
	Federal and State tax credits	—			2,946			(6,817		)
	Foreign income tax rate differential	12,956			24,315			18,682
	Foreign translation adjustments	(11,968		)	(7,744		)	—
	Change in applicable law	—			(5,884		)	—
	Other items, net	11,938			(11,136		)	15,203
	Income tax benefit	$	(22,594	)	$	(70,943	)	$	(54,075	)
	The tax effect of temporary differences and our net operating losses, which give rise to deferred tax assets and liabilities, consisted of the following at December 31, 2014 and 2013:
		At December 31,
		2014			2013
		(In thousands)
	Deferred tax assets:
	Current:
	Inventory	$	30,487		$	2,570
	Other	1,499			2,605
	Total current	31,986			5,175
	Non-current:
	Asset retirement obligation	3,705			—
	Mineral resources	16,832			16,886
	Property, plant and equipment and intangible assets	3,451			21,044
	Stock compensation	2,805			1,964
	Net operating losses	255,588			144,366
	Research and energy tax credits and expenditures	6,141			6,233
	Alternative Minimum Tax Credit	2,216			2,216
	Unrealized foreign exchange	17,380			5,664
	Investments	—			3,120
	Other	5,675			4,107
	Total non-current	313,793			205,600
	Deferred tax liabilities:
Current
Inventory	—			1,312
Other	1,680			1,423
Total current	1,680			2,735
Non-current:
Asset retirement obligation	—			1,190
Foreign subsidiary earnings and withholding taxes	10,423			14,804
Property, plant, equipment and intangible assets	100,076			125,527
Convertible debt (Notes), share lending and other financing arrangements	35,722			44,275
Other	83			302
Total non-current	146,304			186,098
Net deferred taxes, before valuation allowance	197,795			21,942
Valuation allowance	(252,291		)	(107,358		)
Total deferred tax	$	(54,496	)	$	(85,416	)
At December 31, 2014, we had tax credit carryforwards of $7.3 million available to offset future income taxes. Of this amount, $2.2 million is available to carry forward indefinitely, while the remaining $5.1 million will expire between 2024 and 2032, if not utilized.
The U.S. federal tax loss carryforward was approximately $538.0 million at December 31, 2014, of which $28.6 million will expire in 2023 and the remainder in 2032, 2033 and 2034. The U.S. state tax loss carryforward of approximately $436.9 million at December 31, 2014 will expire primarily between 2031 and 2034, if not utilized. The federal loss carryforward could be subject to examination by the tax authorities until three years after the carryforward is utilized while the state carryforward could be subject to examination until four years after the carryforward is utilized. Additionally, we had approximately $231.8 million of tax loss carryforwards for controlled foreign corporations at December 31, 2014 that will expire between 2018 and 2034, if not utilized.
It is possible that past and future transactions involving our common stock may cause an ownership change to occur that would limit our ability to use U.S. net operating loss carryforwards and other tax attributes.
We conduct business in a country that grants “holidays” from income taxes. This “holiday” expires in 2019. The current operations in the tax “holiday” country have not resulted in material aggregate income tax benefits and related earnings per share benefits for the year ended December 31, 2014.
Each quarter, we evaluate the liability for uncertain tax positions. Due to the uncertainty concerning the qualification for a lower tax rate in a foreign jurisdiction, our unrecognized tax benefits increased by $1.2 million during 2014. We believe that it is reasonably possible that the total amount of our net unrecognized income tax benefits will not change materially in the 12 months following December 31, 2014 and, as a result, would not affect our effective income tax rate. A reconciliation of the beginning and ending amount of our gross unrecognized tax benefits is as follows:
	Years Ended December 31,
	2014			2013			2012
	(In thousands)
Balance, beginning of year	$	1,066		$	6,219		$	519
Tax position related to current year:
Additions	1,220			—			4,737
Tax positions related to prior years:
Additions	—			—			16,109
Settlements	—			(4,737		)	(13,740		)
Statute of limitations closures	—			(416		)	(1,406		)
Balance, end of year	$	2,286		$	1,066		$	6,219
We operate, and accordingly file, income tax returns in the U.S. federal jurisdiction, various U.S. state jurisdictions, as well as foreign jurisdictions. With few exceptions, we are no longer subject to U.S. federal, state, and non-U.S. income tax examinations by tax authorities for years prior to 2010. We recognize accrued interest and penalties related to uncertain tax positions in income tax expense.

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity
	2014 Stockholders' Equity Transactions
	Exchange of Convertible Notes
	In fourth quarter of 2014, we issued an aggregate of 15,056,603 shares of our common stock in exchange for $11.0 million aggregate principal amount our 5.50% Convertible Notes and $27.0 million aggregate principal amount our 6.00% Convertible Notes. As a result of this exchange, we recorded a total increase in "Additional paid-in capital" of $16.4 million, offset by $4.8 million representing the difference between the aggregate consideration transferred to the holder and the aggregate fair value of the liability component of each convertible note exchanged. See Note 14 for more information.
	Issuance of Warrants
	On September 11, 2014, as part of the 2014 Financings, we issued warrants to Oaktree to purchase up to an aggregate of 18,358,019 shares of our common stock (the “Penny Warrants”) with an exercise price of $0.01 per share, and warrants to purchase up to an aggregate of 6,119,340 shares of our common stock with an exercise price of $2.04 per share (the “Strike Warrants”, and collectively with the Penny Warrants the “Warrants”). The Warrants may be exercised at any time until September 11, 2019 by Oaktree or any registered holder of the Warrant on either a cash basis (i.e., physical exercise) or on a “cashless basis” by surrendering such Warrant for a net number of shares of our common stock. With respect to the exercise of any Warrant on a “cashless basis”, the number of shares of our common stock to be surrendered is equal to the quotient obtained by dividing (x) the product of the number of shares of our common stock underlying such Warrant or any portion thereof being exercised (at the election of the registered holder), multiplied by the difference between the Fair Market Value and the exercise price by (y) the Fair Market Value. "Fair Market Value" means the average last sale price of a share of our common stock for the ten trading days ending on the third trading day prior to the date on which notice of exercise of such Warrant is sent to Computershare Inc. and Computershare Trust Company, N.A. The exercise price and the number of shares of our common stock issuable upon exercise of the Warrants are subject to customary anti-dilution adjustments for stock splits, stock dividends and recapitalizations of our common stock. Subject to certain exceptions, including the issuance of shares of our common stock or other equity awards pursuant to our equity compensation plans, if we issue common stock (or common stock equivalents) at a purchase price less than the then-current exercise price of the Strike Warrants, the exercise price of the Strike Warrants will be subject to (i) full-ratchet anti-dilution protection for the first two-year period of the Strike Warrants and (ii) weighted-average anti-dilution protection for the remaining three-year period of the Strike Warrants.
	The Penny Warrants meet the criteria for the equity classification and were recorded at a fair value of approximately $24.7 million, less issuance costs of $1.5 million, in "Additional paid-in capital" in the consolidated statement of stockholders' equity. The Strike Warrants, instead, were classified as a derivative liability because the exercise price may be adjusted for the issuance of additional shares of our common stock under certain circumstances. The fair value of the Warrants, which initially was estimated at approximately $3.5 million, was determined using an option-pricing model with the following inputs:
		Penny Warrants			Strike Warrants
	Term (years)	5			5
	Stock price	$	1.55		$	1.55
	Strike price	$	0.01		$	2.04
	Risk-free interest rate	1.79		%	1.79		%
	Volatility	82.6		%	49.9		%
	Dividend yield	—		%	—		%
	Since the unit of account for the Penny Warrants is our common stock, the volatility is based on the average of historical and implied volatility. For the Strike Warrants, we applied a "Volatility Haircut" based on certain studies supporting that market participants would generally apply a discount to the full observed historical or implied volatility for an option on the stock.
	In addition, in order to account for the restriction on the marketability of the shares of common stock issuable upon exercise of the Warrants for a 90-day period from the closing day, we applied a Discount for Lack Of Marketability (“DLOM”) to the fair value of each Warrant obtained from the option-pricing model. The DLOM was obtained using an option-based approach that estimates a discount as an average strike put option, effectively assuming that if the shares of common stock were available to be traded, the holder could sell the shares evenly over the restriction period. In particular, for the Penny Warrants, we discounted the fair value from the option-pricing model by a DLOM of 9%, which resulted into a fair value of $1.40 per Penny Warrant, whereas for the Strike Warrants we discounted the fair value by a DLOM of 31% to arrive to a fair value of $0.57 per Strike Warrant. See Note 24 for information on the fair value of the derivative liability associated with the Strike Warrants.
	Conversion of Preferred Stock
	On March 1, 2014, each share of our 5.50% Series A Mandatory Convertible Preferred Stock (“Convertible Preferred Stock”), which we issued in February 2011 at $100.00 per share, automatically converted into two shares of our common stock based on the “maximum conversion rate”, as defined in our Amended and Restated Certificate of Incorporation. As a result, we issued 4,140,000 shares of our common stock in connection with the automatic conversion of the 2,070,000 shares of the Convertible Preferred Stock. Also on March 1, 2014, we paid the final $2.8 million of the aggregate preferred dividends on the Convertible Preferred Stock to holders of record at the close of business on February 15, 2014. In 2013 and 2012, we declared a quarterly cash dividend of $1.375 per share on the Convertible Preferred Stock and paid a total of $11.4 million cash dividends in each year.
	Share-lending arrangements
	In August 2012, in order to facilitate the offering of our 6.00% Convertible Notes due September 2017, we entered into a share-lending arrangement with Morgan Stanley Capital Services LLC (“MSCS”), an affiliate of Morgan Stanley & Co. LLC, under which we agreed to loan 13,800,000 shares of our common stock to MSCS (the “2012 Borrowed Shares”). In January 2013, in order to facilitate the offering of our 5.50% Convertible Notes due February 2018, we entered into another share-lending arrangement with MSCS, under which we agreed to loan 6,666,666 shares of our common stock (the “2013 Borrowed Shares”, and collectively with the 2012 Borrowed Shares, the “Borrowed Shares”). We received no proceeds and no collateral for the Borrowed Shares, but a nominal lending fee from MSCS for the use of these loaned shares. Given the aggregate lending fees, no further consideration was given to the accounting treatment of the share-lending arrangements. For corporate law purposes, the Borrowed Shares are issued and outstanding. However, based on certain contractual undertakings of MSCS in the share-lending arrangements that have the effect of substantially eliminating the economic dilution that otherwise would result from the issuance of the Borrowed Shares, these loaned shares are not considered outstanding for the purpose of computing and reporting our earnings per share. The Borrowed Shares are to be returned to us concurrently with the maturity of the related convertible notes.
	During the second quarter of 2014, the SEC issued to us a comment letter with respect to our Annual Report on Form 10-K for the fiscal year ended December 31, 2013 regarding, among other things, the fair value measurement of our share-lending arrangements. In response to the SEC’s comment, we reconsidered our approach to determining the fair value of our share-lending arrangements and identified a methodology to estimate the long-term borrowing rate of our common stock, which we adjusted for the credit risk of the counterparty given that no collateral was provided to us. As a result of applying the methodology, we determined that the fair value at the date of issuance of the 2012 Borrowed Shares and 2013 Borrowed Shares should have been approximately $18.1 million and $6.6 million, respectively. These amounts should have been recognized in the financial statements as issuance costs associated with the issuance of the related convertible notes with an offset to "Additional paid-in capital".
	Because the adjustment, both individually and in the aggregate, was not material to any of our prior years’ financial statements, and the impact of correcting the errors was not material to the full year 2014 financial statements, we recorded the correction in the consolidated financial statements in the second quarter of 2014. The out-of-period adjustment had the following impact on the consolidated balance sheet and the consolidated statement of operations and comprehensive loss in 2014:
	Increase to balance sheet captions:	(In thousands)
	Other non-current assets	$	16,381
	Property, plant and equipment, net	3,378
	Additional paid-in capital	15,062
	Increase to statements of operations and comprehensive loss captions:
	Interest expense, net of capitalized interest	4,933
	Income tax benefit	9,630
	The following table provides certain other information on our share-lending arrangements as of December 31, 2014:
		2012 Borrowed Shares			2013 Borrowed Shares			Total
		(In thousands)
	Fair value	$	3,329		$	1,890		$	5,219
	Unamortized issuance cost	9,694			4,174			13,868
	The methodology to fair value our share-lending arrangements consists of an option pricing model that we used to determine a synthetic cost for borrowing our common stock, which we then adjusted for an estimate of the counterparty credit risk. Inputs used in this approach include a combination of Level 2 and Level 3 inputs of the fair value hierarchy. As of December 31, 2014, all of the Borrowed Shares we originally agreed to loan to MSCS are still outstanding, and the related unamortized issuance cost is included in "Other non-current assets" in the consolidated balance sheet.
	The amount of non-cash interest cost recognized relating to the amortization of the issuance cost associated with the combined share-lending arrangements was as follows for the year ended December 31, 2014:
		(In thousands)
	Interest cost expensed	$	7,445
	Interest cost capitalized	3,378
	Total	$	10,823
	2013 Public Equity Issuance (October)
	On October 21, 2013, the Company issued 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 same offering, at a price per share of $5.00. The underwriters received a 5.00% fee in the form of an underwriter's discount. Certain officers, directors and other related parties of the Company participated in this offering by purchasing 14,034,000 of the total shares issued; no underwriting fees were charged to the Company for the purchases of the shares by the insiders. The issuance of these shares resulted in net proceeds to the Company, after deducting the underwriting discounts, commissions and issuance costs payable by the Company, of approximately $247.5 million.
	2013 Public Equity Issuance (January)
	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, and received a 6.00% fee in the form of an underwriter's discount on the total shares issued. 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, commissions and issuance costs payable by the Company, total net proceeds from the issuance of the 2013 Primary Shares were $248.1 million.
	Concurrently with the 2013 Primary Shares, and in order to facilitate the offering of the 5.50% Convertible Notes further discussed in Note 14, 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 were issued at a price per share of $6.00 in a registered public offering. 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 are not considered outstanding for the purpose of computing and reporting Molycorp's earnings per share.
	2012 Private Equity Issuance (Acquisition of Exploration Rights)
	During the fourth quarter of 2012, the Company completed an acquisition of exploration rights for total consideration of $16.2 million, which was paid for by the issuance of 788,410 shares of the Company's common stock at $10.147 per share and a cash payment of $8.2 million. As described in Note 8, the Company recorded an impairment charge of $16.2 million relating to these exploration rights in the fourth quarter of 2013.
	2012 Public Equity Issuance
	In August 2012, concurrently with the issuance of the 6.00% Convertible Notes further discussed in Note 14, the Company issued a total of 13,800,000 shares of its common stock at a price to the public of $10.00 per share (the “Primary Shares”) in a separate underwritten public offering. The underwriters received a 6.00% fee in the form of an underwriter's discount for the Primary Shares plus a $1.5 million flat fee to the representative of the underwriters of the Primary Shares. Certain officers, directors and other related parties of the Company participated in offering of the Primary Shares by purchasing 7,090,000 of the total Primary Shares issued, but no underwriting fees were charged to the Company for the purchase by the insiders. After deducting the underwriting discounts, commissions, the flat fee and issuance costs payable by the Company, total net proceeds from the issuance of the Primary Shares were $132.1 million.
	At the same time of the issuance of the 6.00% Convertible Notes and the Primary Shares the Company entered into a share lending agreement with MSCS and, between August 22, 2012 and August 23, 2012, the Company issued 13,800,000 shares of common stock to MSCS (the 2012 “Borrowed Shares”). The Company received no proceeds from the issuance of the 2012 Borrowed Shares, but only a nominal lending fee from MSCS for the use of these loaned shares. For corporate law purposes, the 2012 Borrowed Shares are issued and outstanding. 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 2012 Borrowed Shares, these loaned shares are not considered outstanding for the purpose of computing and reporting Molycorp's earnings per share.
	2012 Issuance of Shares for Interest in Molycorp Canada
	In connection with of the acquisition of Molycorp Canada on June 11, 2012, we and MCP Exchangeco Inc. issued an aggregate of 13,545,426 shares of our common stock and 507,203 Exchangeable Shares, respectively, in consideration for that portion of the purchase price we paid to Molycorp Canada’s former shareholders who elected to receive shares of our and MCP Exchangeco Inc. common stock in addition to or in lieu of cash on the acquisition date. The Exchangeable Shares were issued without par value. The $284.1 million aggregate fair value of our and MCP Exchangeco Inc. common stock shares was based on the closing price of our common stock on June 11, 2012. As of December 31, 2014, 380,648 shares of the Exchangeable Shares had been converted into shares of Molycorp common stock. The conversion of the Exchangeable Shares increases the outstanding number of shares of our common stock.
	In August 2012, as a result of the conversion of the Debentures assumed from the Molycorp Canada acquisition, as further discussed in Note 14, a portion of the Debentures tendered was converted into 99,723 shares of our common stock. Additional Debentures were converted into 3,225 and 2,471 shares of Molycorp common stock during 2014 and 2013, respectively, for a total of 105,419 shares converted through December 31, 2014.
	2012 Private Equity Issuance (Molymet)
	On March 8, 2012, Molymet, the world’s largest processor of molybdenum and rhenium, headquartered in Santiago, Chile, purchased 12,500,000 shares of our common stock for $390.1 million, net of stock issuance costs of $0.1 million, at a purchase price of $31.218 per share, which price was determined based on the average daily volume weighted average price of the our common stock on The New York Stock Exchange for the 20 consecutive trading days immediately preceding the date of the agreement, plus a 10% premium. Pursuant to this investment, Molymet acquired the right to nominate a member of the our Board of Directors for so long as Molymet owns a certain percentage of our common stock.
	Accumulated Other Comprehensive Income (Loss)
	The following table provides the changes in Accumulated Other Comprehensive Income (Loss) (“AOCI”) for the years ended December 31, 2014, 2013 and 2012:
		Foreign currency translation adjustments			Postretirement benefit liability			Accumulated other comprehensive loss
		(In thousands)
	Balance at December 31, 2011	$	(8,481	)	$	—		$	(8,481	)
	Change in other comprehensive loss before reclassifications	248			(1,200		)	(952		)
	Net income (loss) reclassified from AOCI	—			—			—
	Balance at December 31, 2012	(8,233		)	(1,200		)	(9,433		)
	Change in other comprehensive loss before reclassifications	1,623			1,359			2,982
Net income (loss) reclassified from AOCI	—			—			—
Balance at December 31, 2013	(6,610		)	159			(6,451		)
Change in other comprehensive loss before reclassifications	4,271			(1,143		)	3,128
Net income (loss) reclassified from AOCI	—			—			—
Balance at December 31, 2014	$	(2,339	)	$	(984	)	$	(3,323	)
There were no items reclassified from AOCI during the years presented above.

Loss_per_Share

Loss per Share	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Loss per Share	Loss per Share
		Years Ended December 31,
		2014			2013			2012
		(In thousands, except share and per share amounts)
	Net loss attributable to Molycorp stockholders	$	(604,934	)	$	(374,383	)	$	(481,169	)
	Dividends on Convertible Preferred Stock	(2,846		)	(11,385		)	(11,385		)
	Loss attributable to common stockholders	(607,780		)	(385,768		)	(492,554		)
	Continuing operations	$	(607,780	)	$	(379,341	)	$	(490,817	)
	Discontinued operations	—			(6,427		)	(1,737		)
		$	(607,780	)	$	(385,768	)	$	(492,554	)
	Weighted average common shares outstanding—basic	224,978,752			174,528,717			107,064,892
	Basic loss per share from:
	Continuing operations	$	(2.70	)	$	(2.17	)	$	(4.58	)
	Discontinued operations	—			(0.04		)	(0.02		)
		$	(2.70	)	$	(2.21	)	$	(4.60	)
	Weighted average common shares outstanding—diluted	224,978,752			174,528,717			107,064,892
	Diluted loss per share from:
	Continuing operations	$	(2.70	)	$	(2.17	)	$	(4.58	)
	Discontinued operations	—			(0.04		)	(0.02		)
		$	(2.70	)	$	(2.21	)	$	(4.60	)
	For the years ended December 31, 2014, 2013 and 2012, all potential common stock under the treasury stock method and the if-converted method were antidilutive. Consequently, we did not have any adjustments in these periods between basic loss per share and diluted loss per share related to stock options, restricted stock units and convertible notes.

StockBased_Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	Stock-Based Compensation
	We have stock-based compensation plans for our executives, eligible employees and non-employee directors. Stock-based awards issued under these plans include stock options to purchase shares of our common stock, restricted stock awards (“RSAs”), restricted stock units (“RSUs”) and performance-based restricted stock units ("PBRSUs"). The remaining number of shares authorized for awards of equity share options or other equity instruments was 3,930,494 at December 31, 2014. We recognized total annual stock-based compensation expenses and related income tax benefit as follows:
		2014				2013		2012
		(In thousands)
	Stock-based compensation expense	$	5,261			$	5,392	$	3,434
	RSUs and RSAs vest on the third anniversary of the grant date. The grant-date fair value of RSUs and RSAs is determined using the our common stock price on the date of grant, and it is recognized as stock-based compensation expense on a straight-line basis over the three-year vesting period for the awards that are expected to vest. The PBRSUs vest with respect to between 0% and 150% of the PBRSUs granted to an individual on the basis of the achievement of certain management objectives, as measured by specified levels of total shareholder return relative to a defined index group over a three-year performance period from the grant date, or upon the occurrence of certain change of control or termination events. The grant-date fair value of PBRSUs is determined using a lattice approach that incorporates a Monte Carlo simulation model. The compensation cost associated with the PBRSUs is recognized on a straight-line basis over the performance period for the awards that are expected to vest, even if the market conditions are never satisfied.
	We also grant RSUs to non-employee directors upon their election to convert a portion of their quarterly cash retainer into RSUs. These RSUs are fully vested because they relate to services already rendered by the non-employee directors. The same non-employee directors who elect to convert their cash retainer into RSUs, receive additional RSUs as matching contributions equal to 25% of the converted units. The matching RSUs vest on the third anniversary of the grant date with the related compensation cost recognized on a straight-line basis over the vesting period.
	The following tables summarize the activity related to restricted stock-based awards for the year ended December 31, 2014:
	PBRSUs	Number of			Weighted Average
		Shares			Grant-Date
					Price
	Unvested at December 31, 2013	697,797			$	7.45
	Granted	975,505			4.22
	Forfeited	(41,240	)		6.66
	Vested	(18,246	)		30.33
	Unvested at December 31, 2014	1,613,816			5.28
	RSUs	Number of			Weighted Average
		Shares			Grant-Date
					Price
	Unvested at December 31, 2013	1,076,385			$	9.81
	Granted	1,165,497			3.86
	Forfeited	(71,399	)		8.71
	Vested	(70,998	)		22.98
	Unvested at December 31, 2014	2,099,485			6.1
	RSAs	Number of			Weighted Average
		Shares			Grant-Date
					Price
	Unvested at December 31, 2013	6,326			$	55.05
	Granted	—			—
	Forfeited	—			—
	Vested	—			—
	Unvested at December 31, 2014	6,326			55.05
	Additional annual information for restricted stock-based awards is included in the following tables:
	Weighted average grant-date fair value of shares granted	2014		2013		2012
		(In thousands)
	PBRSUs	$4,117		$6,139		$1,382
	RSUs	4,499		7,060		5,540
	The total fair value of shares vested, and the intrinsic value of share units converted into common stock for all applicable restricted stock-based awards, was nominal in each of the periods presented. At December 31, 2014, there was $11.2 million of aggregate unrecognized compensation cost related to the unvested shares of RSAs, RSUs and PBRSUs. This cost is expected to be recognized over a weighted-average period of approximately 1.78 years.
	We have not granted stock options since January 2011. At December 31, 2014, there were 26,616 stock options outstanding and exercisable, with a weighted average exercise price of $48.87.

Commitments_and_Contingencies

Commitments and Contingencies

12 Months Ended

Dec. 31, 2014

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

Commitments and Contingencies

(a)

Future Operating Lease Commitments

We lease certain office space, trailers and equipment pursuant to lease agreements that have been determined to be operating leases. Remaining annual minimum payments under these leases at December 31, 2014 were as follows:

Total

Less Than

1 - 3 Years

4 - 5 Years

More Than

1 Year

5 Years

(In thousands)

Operating lease obligations

$

6,661

$

2,380

$

3,012

$

508

$

761

Rent expense under these leases totaled $3.1 million, $4.0 million and $4.1 million for the years ended December 31, 2014, 2013 and 2012, respectively.

(b)

Purchase Commitments

We entered into contractual commitments for the purchase of materials and services from various vendors, primarily in connection with the modernization and expansion efforts at our Mountain Pass facility. Future payments for all purchase commitments at December 31, 2014 were as follows:

Total

Less Than

1 - 3 Years

4 - 5 Years

More Than

1 Year

5 Years

(In thousands)

Purchase obligations and other commitments

$

8,187

$

—

8,187

—

—

(c)

Labor Contract

At December 31, 2014, 282 employees, or approximately 59% of the workforce at our Mountain Pass facility were covered by a collective bargaining agreement with the United Steelworkers of America. Our contract with the United Steelworkers of America expires in March 2015. A proposal to renew the contract through March 2018 has been presented to the union for ratification.The union has not ratified the contract renewal yet, and we cannot guarantee that it will be approved. The failure of the union to renew the contract could disrupt operations at our Mountain Pass facility.

Also at December 31, 2014, 155 employees, or approximately 28% of the workforce at our Molycorp Silmet facility, were unionized employees. The contract with the labor union in Estonia is automatically renewed each year unless either party desires to make an amendment.

(d)

Reclamation Surety Bonds

At December 31, 2014, we had placed $28.8 million of surety bonds with California state and regional agencies to secure closure and reclamation obligations at our Mountain Pass facility.

(e)

Purported Class Action, Derivative Lawsuits

In February 2012, a purported class action lawsuit was filed in the Colorado Federal District Court against us and certain of our 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 our Board members and some of our 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 our public offering of preferred stock in February 2011 and of common stock in June 2011, in violation of the Securities Act of 1933. Our motion to dismiss that Complaint was filed in October 2012 and is pending. We believe that this lawsuit is without merit, and we intend to vigorously defend ourselves against these claims.

Certain of our shareholders filed a consolidated stockholder derivative lawsuit purportedly on our behalf against us (as nominal defendant) and certain of our current and former directors, executive officers and shareholders in the Delaware Court of Chancery. A Consolidated Amended Stockholder Derivative Complaint was filed in August 2012. Pursuant to an order dated May 15, 2013, the Delaware Chancery Court stayed this derivative lawsuit pending the outcome of the Colorado class action lawsuit. On October 9, 2013, certain plaintiffs, purportedly on our behalf, filed a Motion to Lift the Stay and for Leave to File an Amended Complaint. Pursuant to a letter opinion dated May 12, 2014, the Delaware Chancery Court granted plaintiffs’ motion to file a second consolidated amended derivative complaint. In addition, the Delaware Chancery Court lifted the stay of the action. The plaintiffs filed their Second Consolidated Amended Complaint on May 15, 2014, alleging breaches of fiduciary duty and unjust enrichment, but dropping claims for material misstatements and for trading on material, non-public information. The defendants filed a Motion to Dismiss the Second Consolidated Amended Complaint on July 14, 2014, and oral arguments on the Motion to Dismiss were heard on January 16, 2015. The Delaware Chancery Court's decision on the Motion to Dismiss is pending.

Two additional shareholder derivative lawsuits were filed purportedly on our behalf against us (as nominal defendant) and certain of our current and former directors, executive officers and shareholders, in the Colorado Federal District Court. These lawsuits allege claims for breach of fiduciary duty, waste of corporate assets, and unjust enrichment based on events in 2011 and 2012. The Colorado Federal District Court dismissed these lawsuits. The plaintiffs filed an appeal of that ruling to the U.S. Court of Appeals for the Tenth Circuit, and the Tenth Circuit remanded these cases back to the Colorado Federal District Court. Subsequently, a different shareholder, purportedly on our behalf, filed a new shareholder derivative lawsuit in the Colorado Federal District Court alleging claims for breach of fiduciary duty, waste of corporate assets, and unjust enrichment based on events during 2011 through 2013. The Colorado Federal District Court sua sponte consolidated this lawsuit with the remanded lawsuits. The plaintiff in the new derivative lawsuit filed a Motion to Vacate the consolidation order. On July 15, 2014, the Colorado Federal District Court ruled that, based on the Second Consolidated Amended Derivative Complaint filed in Delaware Chancery Court, the issues raised in the Colorado derivative cases were sufficiently distinct from the issues set forth in the Delaware derivative lawsuit, and reversed its original order dismissing the lawsuits. In its order, the Colorado Federal District Court left open the opportunity for the defendants to file a motion to stay the Colorado derivative lawsuits pending the resolution of the Colorado class action lawsuit. The motion to say was filed and fully briefed. The Colorado Federal District Court granted the defendants' Motion to Stay all of the Colorado derivative lawsuits pending resolution of the purported Colorado class action lawsuit, and further stayed the new Colorado derivative lawsuit pending resolution of the purported New York class action lawsuit. The Colorado Federal District Court subsequently administratively closed all of the Colorado derivative lawsuits.

In August 2013, two purported class action lawsuits were filed in the U.S. District Court for the Southern District of New York against us and certain of our current and former executive officers, alleging violations of the federal securities laws. A Consolidated Amended Class Action Complaint, filed on May 19, 2014, also names us and certain of our current and former executive officers. The Consolidated Amended Class Action Complaint alleges claims for relief arising out of alleged securities fraud in violation of the Exchange Act, during a purported class period from February 21, 2012 through October 15, 2013. Our Motion to Dismiss the consolidated lawsuit was filed on August 13, 2014. On March 12, 2015, the Federal Court for the Southern District of New York issued an order dismissing the lawsuit with prejudice. The plaintiffs have 14 days to move for reconsideration of the order, and 30 days from the date of entry of the judgment by the Court clerk to file a notice of appeal with the U.S. Court of Appeals for the Second Circuit. We believe that this lawsuit is without merit, and we intend to continue to vigorously defend ourselves against these claims.

The class action and derivative lawsuits described above have not progressed to a point where a reasonably possible range of losses associated with their ultimate outcome can be estimated at this time. If the final resolution of any such litigation or proceedings is unfavorable, our financial condition, operating results and cash flows could be materially affected.

Concentrations

Concentrations	12 Months Ended
	Dec. 31, 2014
Risks and Uncertainties [Abstract]
Concentrations	Concentrations
	Resources Segment
	There were no significant sales by customer or by product at the Resources segment relative to consolidated revenues in each of the three-year periods ended December 31, 2014. We define as significant sales that are 10% or more of consolidated revenues.
	Chemicals and Oxides Segment
	Sales of cerium products within the Chemicals and Oxides segment accounted for approximately 11%, 9% and 15% of consolidated revenues in 2014, 2013 and 2012, respectively. There were no significant sales by customer in this segment in any of these periods.
	Magnetic Materials and Alloys Segment
	Sales of Neo Powders™ within the Magnetic Materials and Alloys segment were approximately 44%, 41% and 25% of consolidated revenues in 2014, 2013 and 2012, respectively. Neo Powders™ were introduced into Molycorp's product mix with the Molycorp Canada acquisition in June 2012.
	Sales of Neo Powders™ to Daido Electronics, a subsidiary of one of IMJ’s shareholders, totaled $62.3 million, $56.5 million and $32.9 million in 2014, 2013 and for the period from June 12, 2012 to December 31, 2012, respectively. At December 31, 2014 and 2013, we had accounts receivable from Daido Electronics of $6.3 million and $7.5 million, respectively.
	Rare Metals Segment
	There were no significant sales by product or by customer at the Rare Metals segment relative to consolidated revenues in each of the three-year period ended December 31, 2014.

RelatedParty_Transactions

Related-Party Transactions	12 Months Ended
	Dec. 31, 2014
Related Party Transactions [Abstract]
Related-Party Transactions	Related-Party Transactions
	We supply Neo Powders™ to Daido Electronics, a subsidiary of one of IMJ’s shareholders, and to Toda Magnequench Magnetic Materials Co. Ltd. (“TMT”), an equity method investee of ours involved in the production of rare earth magnetic compounds. We also purchase magnetic compounds back from TMT in the normal course of business. Two other equity method investees, with whom we regularly buy and sell products, include Ganzhou Keli Rare Earth New Material Co., Ltd. (“Keli”), which processes rare earth oxides into metals for inclusion in our Neo Powders™, and Ingal Stade GmbH, which sells gallium to our rare metals facilities located in Canada and the United States. In addition, we provide rare metal recycling services to Plansee Holding AG ("Plansee"), a privately held Austrian company that is wholly-owned by an Austrian trust, of which one of our Board's directors elected in August 2013 and other members of his family are beneficiaries.
	In 2014, 2013 and for the period from June 12, 2012 to December 31, 2012, we sold $6.0 million, $4.5 million and $1.6 million, respectively, of Neo Powders™ to TMT, and purchased $2.3 million, $2.1 million and $2.8 million, respectively, worth of compounds from TMT.
	We purchased metals and received services from Keli for a total of $63.4 million, $61.3 million and $32.6 million in 2014, 2013 and for the period from June 12, 2012 to December 31, 2012, respectively. As of December 31, 2014, we had a balance payable to Keli of $8.4 million.
	In 2014, 2013 and for the period from June 12, 2012 to December 31, 2012, we purchased gallium metal from Ingal Stade of approximately $2.8 million, $4.9 million and $3.3 million, respectively.
	Transactions with Plansee were nominal in 2014 and 2013. Refer to Note 20 for transactions information with Daido.

Net_Change_in_Operating_Assets

Net Change in Operating Assets and Liabilities	12 Months Ended
	Dec. 31, 2014
Net Change in Operating Assets and Liabilities
Net Change in Operating Assets and Liabilities	Net Change in Operating Assets and Liabilities
	Net change in our operating assets and liabilities, net of the effects of acquisitions and dispositions, consisted of the following in each of the three-year period ended December 31, 2014:
		Years Ended December 31,
		2014			2013			2012
		(In thousands)
	Decrease (increase) in operating assets:
	Trade accounts receivable	$	17,169		$	(8,986	)	$	124,983
	Inventory	(82,390		)	15,649			(46,126		)
	Prepaid expenses and other assets	(4,299		)	(5,728		)	33,520
	Increase (decrease) in operating liabilities:
	Accounts payable	(14,028		)	(24,177		)	(34,972		)
	Income tax payable	2,271			18,966			(40,263		)
	Interest payable	30,181			(39,120		)	(40,792		)
	Asset retirement obligation	(1,606		)	(7,642		)	(1,467		)
	Accrued expenses	3,918			(13,681		)	(54,763		)
		$	(48,784	)	$	(64,719	)	$	(59,880	)

Supplemental_Cash_Flow_Informa

Supplemental Cash Flow Information	12 Months Ended
	Dec. 31, 2014
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	Supplemental Cash Flow Information
		Years Ended December 31,
		2014		2013			2012
		(In thousands)
	Net cash paid for:
	Income taxes	$	13,976	$	(13,429	)	$	178
	Interest, net of capitalized interest	112,575		32,833			8,942
	Non-cash financing activities and investing activities:
	Change in accrued capital expenditures	28,501		58,673			52,189
	Conversion of debt securities to equity securities	38,000		18			4,527
	Acquisition of exploration rights	—		—			8,000
	Debt assumed from business acquisitions	—		—			40,691
	Issuance of common stock for business acquisitions	—		—			284,100
	Fixed assets additions under capital lease	3,612		7,370			15,658

Fair_Value_of_Financial_Instru

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments
	For assets and liabilities that are required under GAAP to be measured at fair value on a recurring or nonrecurring basis, we refer to a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into the following three broad levels:
	•	Level 1 - Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities.
	•	Level 2 - Observable inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly, including quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar assets and liabilities in markets that are not active; or other inputs that are observable or can be corroborated by observable market data by correlation or other means.
	•	Level 3 - Prices or valuation techniques requiring inputs that are both significant to the fair value measurement and unobservable.
	Our assets and liabilities measured at fair value on a recurring basis were as follows at December 31, 2014 and 2013:
		31-Dec-14
		Quoted Prices in Active Markets for Identical Assets/Liabilities		Significant Other Observable Inputs		Significant Unobservable Inputs
		(Level 1)		(Level 2)		(Level 3)
		(In thousands)
	Assets:
	Cash equivalents	$	57,309	—		—
	Liabilities:
	Derivative liabilities:
	Springing Maturity on Term Loans	—		—		$	7,292
	Strike Warrants	—		—		1,769
	Share Purchase Agreement	—		—		6,165
		31-Dec-13
		Quoted Prices in Active Markets for Identical Assets/Liabilities		Significant Other Observable Inputs		Significant Unobservable Inputs
		(Level 1)		(Level 2)		(Level 3)
		(In thousands)
	Assets:
	Cash equivalents	$	179,052	—		—
	Liabilities:
	Derivative liability - Share Purchase Agreement	—		—		$	6,089
	Our financial assets classified in Level 1 consist of money market funds valued based on quoted prices for identical assets in active markets. The fair value of our derivative liabilities is recorded in "Other long-term liabilities" in the balance sheets as of December 31, 2014 and 2013.
	The Springing Maturity on the Term Loans is a derivative liability bifurcated from the Term Loans issued on September 11, 2014 in conjunction with the 2014 Financings, as described in Note 14. The technique used to fair value the Springing Maturity on Term Loans is the income approach based on a discounted cash flow model using significant unobservable inputs, including a probability factor of 10% representing the likelihood that the first of springing maturity dates would be triggered. The change in fair value of the Springing Maturity on Term Loans for the period from September 11, 2014 to December 31, 2014 resulted in a loss of approximately $7.3 million, which we recorded as interest expense in our consolidated statements of operations and comprehensive loss.
	The Strike Warrants were also issued on September 11, 2014 in conjunction with the 2014 Financings. The change in fair value of the Strike Warrants resulted in a gain of approximately $1.7 million for the period from September 11, 2014 to December 31, 2014, which we recorded as interest expense in our consolidated statements of operations and comprehensive loss. The technique used to fair value the Strike Warrants is the income approach based on a discounted cash flow model using significant unobservable inputs, such as the DLOM discussed in Note 16.
	The share purchase agreement (“SPA”) relates to a contract between NMT Holding GmbH, our wholly-owned German subsidiary, and the shareholders of Buss & Buss, a majority-owned subsidiary of ours. 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 us, 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 us. We account for the put option at fair value with changes in fair value recognized currently in earnings. The change in fair value of the put option resulted in a nominal unrealized loss in 2014, and unrealized gains of $1.7 million and $1.2 million for the years ended December 31, 2013 and 2012, respectively, which we recorded as interest expense or income in our consolidated statements of operations and comprehensive loss. The technique used to fair value the SPA is the income approach based on a discounted cash flow model using significant unobservable inputs, including an equity-risk premium of 6.0%, a risk premium of 11.5%, a size premium of 3.8% and a growth rate of 1.0%. Changes to these inputs based on reasonably possible alternative assumptions would not significantly change amounts we recognized in our balance sheets and consolidated statements of operations and comprehensive loss.
	The following table presents the fair value of publicly traded financial liabilities we report at their carrying amount:
		December 31,
		2014					2013
		Carrying Amount		Fair Value			Carrying Amount		Fair Value
		(In thousands)
	3.25% Convertible Notes due June 2016	$	193,549	$	88,281		$	207,028	$	161,771
	6.00% Convertible Notes due September 2017	335,969		107,240			346,708		312,570
	5.50% Convertible Notes due February 2018	143,581		46,028			148,198		164,015
	10% Senior Secured Notes due June 2020	638,899		357,500			637,435		646,750
	Total	$	1,311,998	$	599,049		$	1,339,369	$	1,285,106
	The carrying amount of the financial liabilities listed above is comprised of the principal amount reduced by the unamortized underwriting discount and unamortized issuance costs. In addition, for each of our convertible notes the principal amount is further reduced by the unamortized discount representing the value of the respective equity components at issuance. See Note 14 for more information. The fair value of the financial liabilities listed above, which are all classified in Level 1, is based on the last available market trade of each reporting period. Our Debentures, Term Loans and Equipment 2014 Financings are not actively traded, and the difference between their carrying amount and fair value is impractical to estimate. The carrying amount of certain other financial instruments, such as trade accounts receivables, trade accounts payable, accrued expenses, bank loans and capital lease obligations approximate fair value and, therefore, have been excluded from the table above.
	Contingent forward contract
	On March 28, 2012, we 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 our planned acquisition of Molycorp Canada. We accounted for this contingent forward contract at fair value with changes in fair value recognized in earnings. Upon settlement of this derivative on June 11, 2012 (the Molycorp Canada acquisition date), we recognized a loss of $37.6 million in "Other expense" in our consolidated statement of operations and comprehensive loss for 2012.

Employee_Benefit_Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plans	Employee Benefit Plans
	Defined Contribution Retirement Plans
	We maintain defined contribution retirement plans for all U.S. employees. We make 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, we may determine to make discretionary matching or nonelective employer (profit sharing) contributions in an amount designated by us based on a percentage of employee contributions to the defined contribution plans. Our Safe Harbor matching contributions will always be 100% vested. Employees become 100% vested in our discretionary matching contributions and/or nonelective employer contributions, if any, after 3 years of service.
	Expenses related to this plan totaled $1.5 million, $2.9 million and $1.6 million for the years ended December 31, 2014, 2013 and 2012, respectively. Accrued expenses at December 31, 2014 and 2013 included $0.6 million and $1.9 million related to this plan, respectively.
	Defined Benefit Pension Plan and Other Post-Retirement Benefits
	We maintains plans that provide defined benefit pension benefits as well as postretirement medical and life benefits for the employees of Molycorp Canada’s former manufacturing facility in Anderson, Indiana. The facility was closed in March 2002, and there were 289 participants in the plans at December 31, 2014. The plans had an aggregate benefit obligation of $8.7 million and $7.6 million as of December 31, 2014 and 2013, respectively, while aggregate assets of the plans totaled $5.6 million as of those dates. The plans’ aggregate underfunded status totaled $3.1 million and $2.0 million as of December 31, 2014 and 2013, respectively, and is included in "Other non-current liabilities" in the consolidated balance sheets. Our aggregate net periodic benefit cost were nominal for the years ended December 31, 2014, 2013 and 2012. As of December 31, 2014, the plans’ assets consisted of fixed income securities of $2.7 million, equity securities of $2.5 million and interest bearing cash of $0.4 million.

Subsidiary_Guarantor_Financial

Subsidiary Guarantor Financial Information	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Subsidiary Guarantor Financial Information	Subsidiary Guarantor Financial Information
	The Senior Notes are fully, unconditionally and jointly and severally guaranteed by all of our 100% owned 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 us 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 ours;
	-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 us 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 the Parent ("Molycorp, Inc.") 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 December 31, 2014
		(In thousands)
	Condensed Consolidating Balance Sheets	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations			Molycorp, Inc. consolidated
	Current assets:
	Cash and cash equivalents	$	98,650		$	5,329		$	107,706		$	—		$	211,685
	Trade accounts receivable, net	—			1,924			42,651			—			44,575
	Inventory	—			36,956			132,367			—			169,323
	Prepaid expenses and other current assets	—			9,673			19,659			—			29,332
	Total current assets	98,650			53,882			302,383			—			454,915
	Non-current assets:
	Deposits	1,756			29,322			—			—			31,078
	Property, plant and equipment, net	—			1,575,670			132,300			—			1,707,970
	Inventory	—			25,127			—			—			25,127
	Intangible assets, net	—			377			215,494			—			215,871
	Investments	—			785			8,016			—			8,801
	Goodwill	—			—			102,808			—			102,808
	Investments in consolidated subsidiaries	—			91,672			—			(91,672		)	—
	Intercompany accounts receivable	2,063,568			—			—			(2,063,568		)	—
	Other non-current assets	16,421			7,792			5,203			—			29,416
	Total non-current assets	2,081,745			1,730,745			463,821			(2,155,240		)	2,121,071
	Total assets	$	2,180,395		$	1,784,627		$	766,204		$	(2,155,240	)	$	2,575,986
	Current liabilities:
	Trade accounts payable	$	—		$	14,641		$	26,201		$	—		$	40,842
	Accrued expenses	17,324			16,256			18,386			—			51,966
	Debt and capital lease obligations	—			3,234			9,326			—			12,560
	Other current liabilities	—			263			4,423			—			4,686
	Total current liabilities	17,324			34,394			58,336			—			110,054
	Non-current liabilities:
	Asset retirement obligation	—			17,799			—			—			17,799
	Deferred tax liabilities	—			—			63,802			—			63,802
	Debt and capital lease obligations	1,357,003			146,805			55,973			—			1,559,781
	Intercompany accounts payable	—			2,134,041			658,986			(2,793,027		)	—
	Other non-current liabilities	9,061			1,424			9,762			—			20,247
	Total non-current liabilities	1,366,064			2,300,069			788,523			(2,793,027		)	1,661,629
	Total liabilities	$	1,383,388		$	2,334,463		$	846,859		$	(2,793,027	)	$	1,771,683
	Stockholders’ equity:
	Common stock	260			—			—			—			260
	Additional paid-in capital	2,245,478			132,335			534,440			(666,775		)	2,245,478
	Accumulated other comprehensive loss	(3,323		)	—			(3,323		)	3,323			(3,323		)
	Accumulated deficit	(1,445,408		)	(682,171		)	(619,068		)	1,301,239			(1,445,408		)
	Total Molycorp stockholders’ equity	797,007			(549,836		)	(87,951		)	637,787			797,007
	Noncontrolling interests	—			—			7,296			—			7,296
	Total stockholders’ equity	797,007			(549,836		)	(80,655		)	637,787			804,303
	Total liabilities and stockholders’ equity	$	2,180,395		$	1,784,627		$	766,204		$	(2,155,240	)	$	2,575,986
		At December 31, 2013
		(In thousands)
	Condensed Consolidating Balance Sheets	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations			Molycorp, Inc. consolidated
	Current assets:
	Cash and cash equivalents	$	169,145		$	6,467		$	138,705		$	—		$	314,317
	Trade accounts receivable, net	—			4,990			56,767			—			61,757
	Inventory	—			32,307			139,476			—			171,783
	Prepaid expenses and other current assets	—			15,833			13,377			—			29,210
	Total current assets	169,145			59,597			348,325			—			577,067
	Non-current assets:
	Deposits	1,754			24,243			—			—			25,997
	Property, plant and equipment, net	—			1,620,851			142,023			—			1,762,874
Inventory	—			25,329			—			—			25,329
Intangible assets, net	—			442			330,425			—			330,867
Investments	—			34,134			14,741			—			48,875
Goodwill	—			—			228,750			—			228,750
Investments in consolidated subsidiaries	—			104,327			—			(104,327		)	—
Intercompany accounts receivable	2,534,350			—			—			(2,534,350		)	—
Other non-current assets	—			771			6,272			—			7,043
Total non-current assets	2,536,104			1,810,097			722,211			(2,638,677		)	2,429,735
Total assets	$	2,705,249		$	1,869,694		$	1,070,536		$	(2,638,677	)	$	3,006,802
Current liabilities:
Trade accounts payable	$	—		$	49,702		$	34,747		$	—		$	84,449
Accrued expenses	18,158			13,782			16,561			—			48,501
Debt and capital lease obligations	—			2,234			14,128			—			16,362
Other current liabilities	—			617			3,446			—			4,063
Total current liabilities	18,158			66,335			68,882			—			153,375
Non-current liabilities:
Asset retirement obligation	—			16,966			—			—			16,966
Deferred tax liabilities	—			—			85,481			—			85,481
Debt and capital lease obligations	1,339,368			19,355			5,193			—			1,363,916
Intercompany accounts payable	—			1,999,562			783,011			(2,782,573		)	—
Other non-current liabilities	—			1,393			8,609			—			10,002
Total non-current liabilities	1,339,368			2,037,276			882,294			(2,782,573		)	1,476,365
Total liabilities	$	1,357,526		$	2,103,611		$	951,176		$	(2,782,573	)	$	1,629,740
Stockholders’ equity:
Common stock	241			—			—			—			241
Preferred stock	2			—			—			—			2
Additional paid-in capital	2,194,405			132,335			534,436			(666,771		)	2,194,405
Accumulated other comprehensive loss	(6,451		)	—			(6,451		)	6,451			(6,451		)
Accumulated deficit	(840,474		)	(366,252		)	(437,964		)	804,216			(840,474		)
Total Molycorp stockholders’ equity	1,347,723			(233,917		)	90,021			143,896			1,347,723
Noncontrolling interests	—			—			29,339			—			29,339
Total stockholders’ equity	1,347,723			(233,917		)	119,360			143,896			1,377,062
Total liabilities and stockholders’ equity	$	2,705,249		$	1,869,694		$	1,070,536		$	(2,638,677	)	$	3,006,802
	Year Ended December 31, 2014
	(In thousands)
Condensed Consolidating Statements of Operations and Comprehensive Income	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations			Molycorp, Inc. consolidated
Revenues	$	—		$	60,795		$	452,654		$	(37,837	)	$	475,612
Costs of sales:
Costs excluding depreciation and amortization	—			(181,599		)	(337,655		)	37,837			(481,417		)
Depreciation and amortization	—			(74,119		)	(19,663		)	—			(93,782		)
Gross (loss) profit	—			(194,923		)	95,336			—			(99,587		)
Operating expenses:
Selling, general and administrative	(425		)	(36,768		)	(37,297		)	—			(74,490		)
Depreciation, amortization and accretion	—			(4,946		)	(24,933		)	—			(29,879		)
Research and development	—			(526		)	(14,739		)	—			(15,265		)
Impairment of goodwill and other long-lived assets	—			(13,831		)	(217,819		)	—			(231,650		)
Operating loss	(425		)	(250,994		)	(199,452		)	—			(450,871		)
Other (expense) income:
Other (expense) income	44			(1,853		)	(3,283		)	—			(5,092		)
Foreign exchange (loss) gain, net	(35,914		)	5			32,763			—			(3,146		)
Interest expense, net of capitalized interest	(152,144		)	(14,897		)	(334		)	—			(167,375		)
Gain on extinguishment of convertible notes	19,719			—			—			—			19,719
Impairment of investment	—			(12,000		)	—			—			(12,000		)
Interest income (expense) from intercompany notes	38,525			(2,175		)	(36,350		)	—			—
Equity loss from consolidated subsidiaries	(484,369		)	(12,655		)	—			497,024			—
	(614,139		)	(43,575		)	(7,204		)	497,024			(167,894		)
Loss from continuing operations before income taxes and equity earnings	(614,564		)	(294,569		)	(206,656		)	497,024			(618,765		)
Income tax benefit	9,630			—			12,964			—			22,594
Equity in loss of affiliates	—			(21,350		)	(5,413		)	—			(26,763		)
Net loss	(604,934		)	(315,919		)	(199,105		)	497,024			(622,934		)
Net income attributable to noncontrolling interest	—			—			18,000			—			18,000
Net loss attributable to Molycorp stockholders	$	(604,934	)	$	(315,919	)	$	(181,105	)	$	497,024		$	(604,934	)
Net loss	$	(604,934	)	$	(315,919	)	$	(199,105	)	$	497,024		$	(622,934	)
Other comprehensive income:
Foreign currency translation adjustments	$	—		$	—		$	4,271		$	—		$	4,271
Actuarial loss	—			—			(1,143		)	—			(1,143		)
Comprehensive loss	$	(604,934	)	$	(315,919	)	$	(195,977	)	$	497,024		$	(619,806	)
Comprehensive loss attributable to:
Molycorp stockholders	(604,934		)	(315,919		)	(177,977		)	497,024			(601,806		)
Noncontrolling interest	—			—			(18,000		)	—			(18,000		)
	$	(604,934	)	$	(315,919	)	$	(195,977	)	$	497,024		$	(619,806	)
	Year Ended December 31, 2013
	(In thousands)
Condensed Consolidating Statements of Operations and Comprehensive Income	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations			Molycorp, Inc. consolidated
Revenues	$	—		$	88,266		$	517,202		$	(51,078	)	$	554,390
Costs of sales:
Costs excluding depreciation and amortization	—			(200,650		)	(404,259		)	51,078			(553,831		)
Depreciation and amortization	—			(40,220		)	(27,507		)	—			(67,727		)
Gross (loss) profit	—			(152,604		)	85,436			—			(67,168		)
Operating expenses:
Selling, general and administrative	(190		)	(66,132		)	(40,847		)	—			(107,169		)
Corporate development	—			(247		)	—			—			(247		)
Depreciation, amortization and accretion	—			(6,424		)	(31,613		)	—			(38,037		)
Research and development	—			(5,069		)	(18,103		)	—			(23,172		)
Impairment of goodwill and other long-lived assets	—			(14,250		)	(106,648		)	—			(120,898		)
Operating loss	(190		)	(244,726		)	(111,775		)	—			(356,691		)
Other (expense) income:
Other income (expense)	5			2,169			(288		)	—			1,886
Foreign exchange (loss) gain, net	(9,896		)	11			9,509			—			(376		)
Interest (expense) income, net of capitalized interest	(64,392		)	3,807			(7,099		)	—			(67,684		)
Impairment of investment at cost	—			(9,411		)	—			—			(9,411		)
Interest income (expense) from intercompany notes	36,724			(2,493		)	(34,231		)	—			—
Equity loss from consolidated subsidiaries	(330,604		)	(7,674		)	—			338,278			—
	(368,163		)	(13,591		)	(32,109		)	338,278			(75,585		)
Loss from continuing operations before income taxes and equity earnings	(368,353		)	(258,317		)	(143,884		)	338,278			(432,276		)
Income tax (expense) benefit	(6,030		)	23,130			53,843			—			70,943
Equity in loss of affiliates	—			(6,529		)	(2,640		)	—			(9,169		)
Loss from continuing operations	(374,383		)	(241,716		)	(92,681		)	338,278			(370,502		)
Loss from discontinued operations, net of tax	—			—			(6,427		)	—			(6,427		)
Net loss	(374,383		)	(241,716		)	(99,108		)	338,278			(376,929		)
Net income attributable to noncontrolling interest	—			—			2,546			—			2,546
Net loss attributable to Molycorp stockholders	$	(374,383	)	$	(241,716	)	$	(96,562	)	$	338,278		$	(374,383	)
Net loss	$	(374,383	)	$	(241,716	)	$	(99,108	)	$	338,278		$	(376,929	)
Other comprehensive income:
Foreign currency translation adjustments	$	—		$	—		$	1,623		$	—		$	1,623
Actuarial gain	—			—			1,359			—			1,359
Comprehensive loss	$	(374,383	)	$	(241,716	)	$	(96,126	)	$	338,278		$	(373,947	)
Comprehensive loss attributable to:
Molycorp stockholders	(374,383		)	(241,716		)	(93,580		)	338,278			(371,401		)
Noncontrolling interest	—			—			(2,546		)	—			(2,546		)
	$	(374,383	)	$	(241,716	)	$	(96,126	)	$	338,278		$	(373,947	)
	Year Ended December 31, 2012
	(In thousands)
Condensed Consolidating Statements of Operations and Comprehensive Income	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations			Molycorp, Inc. consolidated
Revenues	$	—		$	139,257		$	413,951		$	(25,512	)	$	527,696
Costs of sales:
Costs excluding depreciation and amortization	—			(153,461		)	(350,304		)	25,512			(478,253		)
Depreciation and amortization	—			(12,094		)	(18,527		)	—			(30,621		)
Gross (loss) profit	—			(26,298		)	45,120			—			18,822
Operating expenses:
Selling, general and administrative	46			(86,493		)	(26,990		)	—			(113,437		)
Corporate development	(46		)	(19,750		)	—			—			(19,796		)
Depreciation, amortization and accretion	—			(2,220		)	(19,967		)	—			(22,187		)
Research and development	—			(12,984		)	(14,812		)	—			(27,796		)
Impairment of goodwill and other long-lived assets	—			(5,747		)	(296,008		)	—			(301,755		)
Operating loss	—			(153,492		)	(312,657		)	—			(466,149		)
Other (expense) income:
Other expense	(37,589		)	(328		)	(881		)	—			(38,798		)
Foreign exchange gain, net	—			—			2,872			—			2,872
Interest expense, net of capitalized interest	(18,118		)	(3,496		)	(502		)	—			(22,116		)
Interest income (expense) from intercompany notes	25,157			3,152			(28,309		)	—			—
Equity loss from consolidated subsidiaries	(456,649		)	(23,205		)	—			479,854			—
	(487,199		)	(23,877		)	(26,820		)	479,854			(58,042		)
Loss from continuing operations before income taxes and equity earnings	(487,199		)	(177,369		)	(339,477		)	479,854			(524,191		)
Income tax benefit (expense)	6,030			53,840			(5,795		)	—			54,075
Equity in loss of affiliates	—			(2,439		)	(1,051		)	—			(3,490		)
Loss from continuing operations	(481,169		)	(125,968		)	(346,323		)	479,854			(473,606		)
Loss from discontinued operations, net of tax	—			—			(1,737		)	—			(1,737		)
Net loss	(481,169		)	(125,968		)	(348,060		)	479,854			(475,343		)
Net income attributable to noncontrolling interest	—			—			(5,826		)	—			(5,826		)
Net loss attributable to Molycorp stockholders	$	(481,169	)	$	(125,968	)	$	(353,886	)	$	479,854		$	(481,169	)
Net loss	$	(481,169	)	$	(125,968	)	$	(348,060	)	$	479,854		$	(475,343	)
Other comprehensive income:
Foreign currency translation adjustments	—			—			248			—			248
Actuarial loss	—			—			(1,200		)	—			(1,200		)
Comprehensive loss	$	(481,169	)	$	(125,968	)	$	(349,012	)	$	479,854		$	(476,295	)
Comprehensive loss attributable to:
Molycorp stockholders	(481,169		)	(125,968		)	(354,838		)	479,854			(482,121		)
Noncontrolling interest	—			—			5,826			—			5,826
	$	(481,169	)	$	(125,968	)	$	(349,012	)	$	479,854		$	(476,295	)
	Year Ended December 31, 2014
	(In thousands)
Condensed Consolidating Statements of Cash Flows	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations			Molycorp, Inc. consolidated
Net cash (used in) provided by operating activities	$	(65,618	)	$	(178,939	)	$	22,353		$	—		$	(222,204	)
Cash flows from investing activities:
Intercompany advances made	(111,753		)	(2,123		)	(55,578		)	169,454			—
Repayments from non-guarantor	39,662			—			—			(39,662		)	—
Loans to guarantors	—						(6,655		)	6,655			—
Loans to non-guarantors	(4,000		)	(5,000		)	—			9,000			—
Investment in joint ventures	—			—			(703		)	—			(703		)
Dividends received from equity investment	—			—			2,014			—			2,014
Capital expenditures	—			(78,557		)	(7,601		)	—			(86,158		)
Recovery from insurance claims	—			12,900			—			—			12,900
Other investing activities	—			90			894			—			984
Net cash used in investing activities	(76,091		)	(72,690		)	(67,629		)	145,447			(70,963		)
Cash flows from financing activities:
Repayments of debt	—			—			(7,825		)	—			(7,825		)
Debt issuance costs	(4,190		)	(7,750		)	(3,320		)	—			(15,260		)
Proceeds from the 2014 Financings	50,167			139,833			60,000			—			250,000
Partial repayment of convertible notes	(27,495		)	—			—			—			(27,495		)
Payments of preferred dividends	(2,846		)	—			—			—			(2,846		)
Dividend paid to noncontrolling interests	—			—			(4,222		)	—			(4,222		)
Borrowing from non-guarantor	—			6,655			—			(6,655		)	—
Borrowings from parent	—			—			4,000			(4,000		)	—
Borrowings from guarantor	—			—			5,000			(5,000		)	—
Repayments to parent	—			—			(39,662		)	39,662			—
Intercompany advances owed	55,578			111,753			2,123			(169,454		)	—
Net cash provided by financing activities	71,214			250,491			16,094			(145,447		)	192,352
Effect of exchange rate changes on cash	—			—			(1,817		)	—			(1,817		)
Net change in cash and cash equivalents	(70,495		)	(1,138		)	(30,999		)	—			(102,632		)
Cash and cash equivalents at beginning of the period	169,145			6,467			138,705			—			314,317
Cash and cash equivalents at end of period	$	98,650		$	5,329		$	107,706		$	—		$	211,685
	Year Ended December 31, 2013
	(In thousands)
Condensed Consolidating Statements of Cash Flows	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations			Molycorp, Inc. consolidated
Net cash (used in) provided by operating activities	$	(39,075	)	$	(133,612	)	$	18,336		$	—		$	(154,351	)
Cash flows from investing activities:
Loans to guarantor	—			—			(40,000		)	40,000			—
Loans to Parent	—			—			(12,800		)	12,800			—
Intercompany advances made	(391,560		)	—			—			391,560			—
Loans to non-guarantor	(117,512		)	(1,300		)	—			118,812			—
Repayments of notes receivable from non-guarantor	38,000			117,776			—			(155,776		)	—
Investment in joint ventures	—			(3,423		)	—			—			(3,423		)
Capital expenditures	—			(361,782		)	(17,530		)	—			(379,312		)
Other investing activities	—			4,902			575			—			5,477
Net cash used in investing activities	(471,072		)	(243,827		)	(69,755		)	407,396			(377,258		)
Cash flows from financing activities:
Repayments of debt	—			—			(26,823		)	—			(26,823		)
Net proceeds from sale of common stock	495,717			—			—			—			495,717
Issuance of 5.50% Convertible Notes	165,600			—			—			—			165,600
Payments of preferred dividends	(11,385		)	—			—			—			(11,385		)
Dividend paid to noncontrolling interests	—			—			(4,546		)	—			(4,546		)
Borrowing from non-guarantor	12,800			40,000			—			(52,800		)	—
Borrowings from parent	—			—			117,512			(117,512		)	—
Borrowings from guarantor	—			—			1,300			(1,300		)	—
Repayments to parent	—			—			(38,000		)	38,000			—
Repayments to guarantor	—			—			(117,776		)	117,776			—
Intercompany advances owed	—			327,183			64,377			(391,560		)	—
Other financing activities	—			(1,297		)	—			—			(1,297		)
Net cash provided by financing activities	662,732			365,886			(3,956		)	(407,396		)	617,266
Effect of exchange rate changes on cash	—			—			870			—			870
Net change in cash and cash equivalents	152,585			(11,553		)	(54,505		)	—			86,527
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	$	169,145		$	6,467		$	138,705		$	—		$	314,317
	Year Ended December 31, 2012
	(In thousands)
Condensed Consolidating Statements of Cash Flows	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations			Molycorp, Inc. consolidated
Net cash (used in) provided by operating activities	$	(13,207	)	$	(112,386	)	$	35,958		$	—		$	(89,635	)
Cash flows from investing activities:
Cash paid in connection with acquisitions, net of cash acquired	—			—			(591,011		)	—			(591,011		)
Loans to subsidiaries	(697,213		)	—			—			697,213			—
Loans to Parent	—			(37,589		)	—			37,589			—
Intercompany advances made	(1,009,014		)	—			—			1,009,014			—
Repayments from subsidiaries	101,974			—			—			(101,974		)	—
Investment in subsidiaries	(350,000		)	—			—			350,000			—
Notes receivable to non-guarantor	—			(227,512		)	—			227,512			—
Repayments of notes receivable from non-guarantor	—			110,000			—			(110,000		)	—
Investment in joint ventures	—			(27,680		)	(5,364		)	—			(33,044		)
Capital expenditures	—			(766,951		)	(24,518		)	—			(791,469		)
Acquisition of exploration rights	—			—			(8,167		)	—			(8,167		)
Other investing activities	—			(3,999		)	4,761			—			762
Net cash used in investing activities	(1,954,253		)	(953,731		)	(624,299		)	2,109,354			(1,422,929		)
Cash flows from financing activities:
Capital contributions from stockholder	390,093			—			—			—			390,093
Capital contributions from Parent	—			—			350,000			(350,000		)	—
Repayments of debt	—			(870		)	(227,838		)	—			(228,708		)
Net proceeds from sale of common stock	132,130			—			—			—			132,130
Issuance of 10% Senior Secured Notes	635,373			—			—			—			635,373
Issuance of 6.00% Convertible Notes	395,712			—			—			—			395,712
Payments of preferred dividends	(11,385		)	—			—			—			(11,385		)
Dividend paid to noncontrolling interests	—			—			(5,977		)	—			(5,977		)
Proceeds from debt	—			—			14,699			—			14,699
Borrowings from parent	—			227,512			469,701			(697,213		)	—
Repayments of borrowings to parent	—			(34,327		)	(67,647		)	101,974			—
Borrowing from guarantor	37,589			—			227,512			(265,101		)	—
Repayments of borrowings to guarantor	—			—			(110,000		)	110,000			—
Intercompany advances owed	—			881,179			127,835			(1,009,014		)	—
Other financing activities	(2,938		)	(115		)	1,499			—			(1,554		)
Net cash provided by financing activities	1,576,574			1,073,379			779,784			(2,109,354		)	1,320,383
Effect of exchange rate changes on cash	—			—			1,116			—			1,116
Net change in cash and cash equivalents	(390,886		)	7,262			192,559			—			(191,065		)
Cash and cash equivalents at beginning of the period	407,446			10,758			651			—			418,855
Cash and cash equivalents at end of period	$	16,560		$	18,020		$	193,210		$	—		$	227,790
During the fourth quarter of 2014, we identified two classification errors affecting the Condensed Consolidating Balance Sheets at December 31, 2013 with respect to the Parent's investment in the Non-Guarantors subsidiaries and the investment of one of the Guarantor subsidiaries' in the other Guarantor subsidiary, and one classification error affecting the Condensed Consolidating Statements of Cash Flows for the year ended December 31, 2012 with respect to a loan between the Parent and one of the Non-Guarantor subsidiaries. The changes in the presentation of the Condensed Consolidating Balance Sheets at December 31, 2013 and the Condensed Consolidating Statements of Cash Flows for the year ended December 31, 2012 are as follows:
Condensed Consolidating Balance Sheets	At December 31, 2013
	(In thousands)
Parent	As reported			Adjustment			Revised
Investments in consolidated subsidiaries	$	532,767		$	(532,767	)	$	—
Intercompany accounts receivable	2,001,583			532,767			2,534,350
Guarantor Subsidiaries							—
Investments in consolidated subsidiaries	$	121,849		$	(17,522	)	$	104,327
Additional paid-in capital	149,857			(17,522		)	132,335
Non-Guarantor Subsidiaries							—
Intercompany accounts payable	$	2,021		$	780,990		$	783,011
Additional paid-in capital	1,315,426			(780,990		)	534,436
Condensed Consolidating Statements of Cash Flows	At December 31, 2012
	(In thousands)
Parent	As reported			Adjustment			Revised
Loans to subsidiaries	$	(683,063	)	$	(14,150	)	$	(697,213	)
Repayments from subsidiaries	87,824			14,150			101,974
Non-Guarantor Subsidiaries							—
Borrowing from parent	$	455,551		$	14,150		$	469,701
Repayments of borrowings to parent	(53,497		)	(14,150		)	(67,647		)

Discontinued_Operations

Discontinued Operations	12 Months Ended
	Dec. 31, 2014
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations	Discontinued Operations
	On March 3, 2014, we completed the disposition of the Napanee (Ontario), Canada facility where we used to recycle rhenium bearing scrap under the Rare Metals segment. The following table summarizes the operating results of the Napanee facility included in discontinued operations for the years ended December 31, 2013 and 2012:
		December 31,			June 12 -December 31,
		2013			2012
		(In thousands)
	Revenues	$	2,091		$	1,214
	Costs of sales	(3,834		)	(2,691		)
	Selling, general and administrative expenses	(351		)	(232		)
	Depreciation	(28		)	(28		)
	Operating loss	(2,122		)	(1,737		)
	Impairment loss	(4,305		)	—
	Income tax	—			—
	Net loss	$	(6,427	)	$	(1,737	)

Unaudited_Supplementary_Data

Unaudited Supplementary Data	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Unaudited Supplementary Data	Unaudited Supplementary Data
	The following is a summary of the selected quarterly financial information (unaudited):
		2014
		Quarter ended
		31-Mar			30-Jun			30-Sep			31-Dec
		(In thousands, except per share data)
	Revenues	$	118,526		$	116,907		$	123,937		$	116,242
	Gross loss	(23,094		)	(16,571		)	(15,078		)	(44,844		)
	Loss from continuing operations before income taxes and equity earnings (a)	(86,182		)	(89,724		)	(99,484		)	(343,375		)
	Net loss	(85,998		)	(83,850		)	(105,148		)	(347,938		)
	Net loss attributable to Molycorp stockholders (b)	(86,061		)	(83,899		)	(105,179		)	(329,795		)
	Loss per share of common stock from continuing operations: (c)
	Basic	(0.40		)	(0.37		)	(0.47		)	(1.43		)
	Diluted	(0.40		)	(0.37		)	(0.47		)	(1.43		)
		2013
		Quarter ended
		31-Mar			30-Jun			30-Sep			31-Dec
		(In thousands, except per share data)
	Revenues	$	145,398		$	136,112		$	149,066		$	123,814
	Gross loss	(4,305		)	(18,036		)	(17,778		)	(27,049		)
	Loss from continuing operations before income taxes and equity earnings (d)	(57,249		)	(70,254		)	(76,181		)	(228,592		)
	Net loss	(38,153		)	(70,689		)	(69,799		)	(198,288		)
	Net loss attributable to Molycorp stockholders	(38,971		)	(71,175		)	(69,929		)	(194,308		)
	Loss per share of common stock from continuing operations: (c)
	Basic	(0.27		)	(0.44		)	(0.43		)	(0.95		)
	Diluted	(0.27		)	(0.44		)	(0.43		)	(0.95		)
	(a)	Includes the following adjustments:
	i.	Second quarter out-of-period adjustment of $4.9 million (see Note 16);
	ii.	Third quarter impairment charge of $12.0 million (see Note 10);
	iii.	Fourth quarter out-of-period adjustment of $3.8 million (see Note 3);
	iv.	Fourth quarter impairment charges for: goodwill, $125.9 million; customer relationships, $90.9 million; long-lived tangible assets, 14.4 million; net gain on extinguishment of convertible notes, $19.7 million (see Notes 7, 9 and 14, respectively).
	(b)	Includes charges for equity method investments write-off totaling $19.7 million (see Note 10).
	(c)	The sum of the quarterly loss per share may be different than the per share amount for the year as the calculation for each quarter is based on the weighted average shares outstanding for that period.
	(d)	Includes the following impairment charges in the fourth quarter: goodwill, $11.0 million; rare earths quotas, $67.2 million; patents, $10.2 million; exploration rights, $16.2 million; cost method investments, $9.4 million; and long-lived tangible assets, $16.3 million (see Notes 7, 9 and 10).

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation
	The accompanying consolidated financial statements, which are prepared in accordance with GAAP, include our accounts and the accounts of our majority-owned subsidiaries where we exert control. Investments in which we do not have control, and are not considered to be the primary beneficiary of a variable interest entity, but where we exercise significant influence over the operating and financial policies of the investee, are accounted for using the equity method of accounting. All other investments are accounted for at cost. Intercompany balances and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates
	The preparation of the consolidated financial statements, in accordance with GAAP, requires us 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. We base our estimates on historical experience and on various other assumptions that we believe to be reasonable under the circumstances. Actual results may differ significantly from these estimates under different assumptions and conditions. Significant estimates we made in the accompanying financial statements include our ability to collect 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, and the adequacy of the asset retirement obligation.
Revenues and Costs of Sales	Revenues and Costs of Sales
	Revenues are recognized when persuasive evidence of an arrangement exists, the risks and rewards of ownership have been transferred to the customer, which is generally when title passes, the selling price is fixed or determinable, and collection is reasonably assured. Title generally passes to the customer upon shipment of product from our facilities. Certain contracts with customers contain provisions whereby title passes upon loading the product at the shipping port. Prices are generally set at the time of, or prior to, shipment. Transportation and distribution costs are incurred only on sales for which we are responsible for delivering the product.
	Costs of sales include costs of production and write downs of inventory to market value. Primary production costs include labor, raw materials, depreciation, supplies, maintenance costs and plant overhead.
Cash and Cash Equivalents	Cash and Cash Equivalents
	Cash and cash equivalents consist of cash and liquid investments with an original maturity of three months or less. Because of the short maturity of these investments, the carrying amounts approximate their fair values.
Trade Accounts Receivable	Trade Accounts Receivable
	Trade accounts receivable are recorded at the invoiced amount and do not bear interest. We review the need for an allowance for doubtful accounts quarterly based on historical experience with each customer and the specifics of each arrangement.
Inventory	Inventory
	Inventory consists of stockpiles of crushed ore, bastnasite concentrate, raw materials, work in process, finished goods and materials and supplies. Inventory cost is determined using the lower of weighted average cost or estimated net realizable market value, and includes all expenses directly attributable to the manufacturing process as well as production overheads based on normal operating capacity. We evaluate the carrying amount of inventory each quarter giving consideration to slow-moving items, obsolescence, excessive levels, and other factors and recognizes related write-downs as necessary. Write-downs of inventory to estimated market value are charged to costs of sales. Inventory expected to be used and sold beyond a twelve-month period is classified as a non-current asset in the consolidated balance sheets.
Property, Plant and Equipment	Property, Plant and Equipment
	Property, plant and equipment obtained in business acquisitions are recorded at their estimated fair value as of the acquisition date. Expenditures for new property, plant and equipment, and improvements that extend the useful life or functionality of the asset are recorded at their cost of acquisition or construction. Depreciation on property, plant and equipment is provided using the straight-line method over their estimated useful lives. Maintenance costs are expensed as incurred.
	Construction in progress includes costs directly attributable to the construction or development of long-term tangible assets. These costs may include: labor and employee benefits associated with the construction of the asset; site preparation; permitting; engineering; installation and assembly; procurement; insurance; legal; commissioning; and interest on borrowings to finance the construction of the asset. Depreciation is not recorded on the related assets until they are placed in service or ready for their intended use.
	Gains or losses arising on the disposal of property, plant and equipment are determined as the difference between the proceeds from disposal and the carrying amount of the asset, and are included in other income (expense) in the consolidated statements of operations and comprehensive loss.
Mineral Properties and Development Costs	Mineral Properties and Development Costs
	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, all of which are capitalized. We deplete mineral properties using the units of production method over estimated proven and probable reserves. Depletion expense is an inventoriable cost.
Intangible Assets	Intangible Assets
	Intangible assets consist primarily of customer relationships, patents and other intellectual properties, Chinese land use rights and both indefinite-lived and finite-lived trade names. Finite-lived intangible assets are amortized on a straight-line basis over the estimated useful lives, which range from 2 to 16 years for customer relationships, patents and trade name, and 50 years for Chinese land use rights.
Recoverability of Long-Lived Depreciable/Amortizable Assets	Recoverability of Long-Lived Depreciable/Amortizable Assets
	Long-lived assets such as property, plant, and equipment, mineral properties and intangible assets that are depreciated or amortized, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset or asset group may not be recoverable. An impairment is considered to exist if the total undiscounted future cash flows expected from the use of the asset or asset group are less than its carrying amount. An impairment loss, if any, is recorded for the excess of the asset's or asset group's carrying amount over its fair value, as determined by a valuation technique appropriate to the given circumstances.
Recoverability of Goodwill	Recoverability of Goodwill
	We assign goodwill arising from acquired companies to the reporting units that are expected to benefit from the acquisition. On an annual basis or in interim periods when circumstances require, we test the recoverability of our goodwill utilizing a two-step impairment analysis. Under this analysis, we initially compare the fair value of each identified reporting unit with the reporting unit's carrying amount. Our reporting units are determined either at the operating segment level or a component one level below the operating segment that constitutes a business for which the operating segment's management generally reviews production and financial results. To the extent that a reporting unit's fair value is less than its carrying amount, we perform an additional step to determine the implied fair value of the reporting unit's goodwill. The implied fair value of goodwill is calculated by first allocating the reporting unit's fair value to its assets and liabilities, excluding goodwill, and then comparing the excess of the reporting unit's fair value to the carrying amount of goodwill. To the extent that the carrying amount of goodwill exceeds its implied fair value, we would recognize an impairment loss. The valuation methodology utilized to determine the fair value of our reporting units is based on a discounted cash flow model, or income approach, in which expected future net cash flows, excluding any financing costs or dividends, are discounted using an appropriate discount rate. The income approach is dependent upon a number of significant management estimates about future performance including expected sales volumes, sales prices, production costs, income taxes, capital expenditures, working capital changes, foreign exchange rates and the after-tax weighted average cost of capital. Changes in any of these assumptions could materially impact the estimated fair value of our reporting units. Discount factors are determined individually for each reporting unit to reflect its respective risk profile as assessed by us.
Investments	Investments
	Investments in non-marketable equity securities of entities in which we have the ability to exercise significant influence over the entity's operating and financial policies are accounted for by the equity method. We recognize our proportionate share of the entity’s income or loss each period with such amounts included in "Equity in income (loss) of affiliates" in the consolidated statements of operations and comprehensive income (loss). Equity method investments are reviewed periodically for other-than-temporary decline in value. Investments in non-marketable equity securities of entities for which we do not have the ability to exercise significant influence over the entity’s operations and financial policies are accounted for at cost, and are subject to periodic other-than-temporary impairment assessments.
Business Combinations	Business Combinations
	We account for all business combinations using the acquisition method of accounting. Under this method, assets and liabilities, including any noncontrolling interests, are recognized at fair value at the date of acquisition. The excess of the purchase price over the fair value of assets acquired, net of liabilities assumed, and noncontrolling interests is recognized as goodwill. Certain adjustments to the assessed fair values of the assets, liabilities, or noncontrolling interests made subsequent to the acquisition date, but within the measurement period, which is up to one year, are recorded as adjustments to goodwill. Any adjustments subsequent to the measurement period are recorded in income. Any cost or equity method interest that we hold in the acquired company prior to the acquisition is remeasured to fair value at acquisition with a resulting gain or loss recognized in income for the difference between fair value and the existing book value. Results of operations of the acquired entity are included in our results from the date of the acquisition. We expense all costs as incurred related to an acquisition under “Corporate development” in the consolidated statement of operations and comprehensive income (loss).
Asset Retirement Obligation	Asset Retirement Obligation
	We account for reclamation costs, along with other costs related to the closure of our Mountain Pass facility, in accordance with ASC 410-20, Asset Retirement Obligations, which requires us to recognize an ARO at its estimated fair value in the period in which the obligation is incurred. Events that trigger the recognition of an ARO include land disturbances and construction of a property for which there is a legal obligation to restore the land and the property to their original state. The liability is initially measured at fair value using a discounted cash flow model, and is subsequently adjusted for accretion expense and changes in the amount or timing of the estimated cash flows. A corresponding asset retirement cost is capitalized as part of the carrying amount of the related long-lived assets and is amortized over the assets’ remaining useful lives.
Income Taxes	Income Taxes
	We account for income taxes in accordance with Accounting Standard Codification 740, Income Taxes, which requires that deferred tax assets and liabilities be recognized for the tax effect of temporary differences between the financial statement and tax basis of recorded assets and liabilities at enacted statutory tax rates. This guidance also requires that deferred tax assets be reduced by a valuation allowance if it is more likely than not that some portion or all of the deferred tax assets will not be realized based on both our historical and anticipated earnings levels. We review our deferred tax assets each reporting period to determine if adjustments to the valuation allowance are necessary.
	We record our deferred tax assets and liabilities using enacted tax rates expected to apply to taxable income for the period in which the deferred tax assets or liabilities are expected to be realized. The statutory income tax rates that are applied to the current and deferred income tax calculations differ by the jurisdictions in which we conduct business. Changes in such income tax rates and apportionment laws may result in changes in our deferred income tax assets, liabilities and related expense in the period of enactment.
Foreign Currency	Foreign Currency
	The functional currency of the majority of our operations is the U.S. dollar. Assets and liabilities recorded in functional currencies other than the functional currency are translated at the spot rate in effect at the applicable reporting date; revenues and expenses in foreign currencies are translated at actual exchange rates for significant transactions or at the average exchange rates in effect during the applicable period. The resulting unrealized cumulative translation adjustment is recorded as a component of "Accumulated other comprehensive income (loss)" in the consolidated balance sheets. The effect of exchange rates on cash balances held in foreign currencies are separately reported in our consolidated statements of cash flows.
	Transactions denominated in currencies other than the applicable functional currency are recorded based on exchange rates at the time such transactions occur. Changes in exchange rates associated with monetary amounts recorded in our consolidated balance sheets related to these non-functional currency transactions result in transaction gains and losses that are reflected in "Foreign exchange gains (losses), net" in the consolidated statements of operations and comprehensive income (loss).
	Correction of Functional Currency
	As part of our acquisition of Molycorp Silmet on April 1, 2011, we determined that its functional currency was the Euro. During the fourth quarter of 2014, we reconsidered a number of economic indicators that apply to the operations of Molycorp Silmet and concluded that the U.S. dollar should have been the functional currency that most faithfully represents the economic effects of its underlying transactions. Because this misstatement, both individually and in the aggregate, was not material to any of our prior years’ financial statements, and the impact of correcting it was not material to the full-year 2014 financial statements, we adjusted the cumulative effect of changing the functional currency of Molycorp Silmet in the fourth quarter of 2014.
Comprehensive Income (Loss)	Comprehensive Income (Loss)
	We present comprehensive income (loss) in two separate, but consecutive statements. In addition to "Net income (loss)", "Comprehensive income (loss)" includes foreign currency translation adjustments and actuarial gains and losses associated with the defined benefit pension benefits and post-retirement benefits for the employees of one of Molycorp Canada’s former manufacturing facilities.
Earnings (Loss) per Share	Earnings (Loss) per Share
	Basic earnings (loss) per share is computed by dividing our net income (loss) attributable to our stockholders, reduced by cumulative undeclared and paid dividends on any outstanding preferred stock, by the weighted average number of shares of common stock outstanding during the period.
	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, are deemed options for purposes of computing diluted earnings per share. 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. 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.
Research and Development	Research and Development
	Research and development costs, which consist primarily of salaries, outside labor, material and equipment, are expensed as incurred.
Recent Accounting Pronouncements	Recent Accounting Pronouncements
	In August 2014, the FASB issued ASU 2014-15, Presentation of Financial Statements - Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern. This update provides guidance about management’s responsibilities in evaluating an entity’s going concern uncertainties, and about the timing and content of related footnote disclosures. Under this amended guidance, an entity’s management should evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the entity’s ability to continue as a going concern within one year after the date that the financial statements are issued (or within one year after the date that the financial statements are available to be issued when applicable). Management’s evaluation should be based on relevant conditions and events that are known and reasonably knowable at the date that the financial statements are issued (or at the date that the financial statements are available to be issued when applicable). Substantial doubt about an entity’s ability to continue as a going concern exists when relevant conditions and events, considered in the aggregate, indicate that it is probable that the entity will be unable to meet its obligations as they become due within one year after the date that the financial statements are issued (or available to be issued). The term probable is used consistently with its use in Topic 450, Contingencies. When management identifies conditions or events that raise substantial doubt about an entity’s ability to continue as a going concern, management should consider whether its plans that are intended to mitigate those relevant conditions or events will alleviate the substantial doubt. The mitigating effect of management’s plans should be considered only to the extent that (1) it is probable that the plans will be effectively implemented and, if so, (2) it is probable that the plans will mitigate the conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern. If conditions or events raise substantial doubt about an entity’s ability to continue as a going concern, but the substantial doubt is alleviated as a result of consideration of management’s plans, the entity should disclose information that enables users of the financial statements to understand all of the following (or refer to similar information disclosed elsewhere in the footnotes):
	a. Principal conditions or events that raised substantial doubt about the entity’s ability to continue as a going concern (before consideration of management’s plans);
	b. Management’s evaluation of the significance of those conditions or events in relation to the entity’s ability to meet its obligations; and
	c. Management’s plans that alleviated substantial doubt about the entity’s ability to continue as a going concern.
	If conditions or events raise substantial doubt about an entity’s ability to continue as a going concern, and substantial doubt is not alleviated after consideration of management’s plans, an entity should include a statement in the footnotes indicating that there is substantial doubt about the entity’s ability to continue as a going concern within one year after the date that the financial statements are issued (or available to be issued). Additionally, the entity should disclose information that enables users of the financial statements to understand all of the following:
	a. Principal conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern;
	b. Management’s evaluation of the significance of those conditions or events in relation to the entity’s ability to meet its obligations; and
	c. Management’s plans that are intended to mitigate the conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern.
	This update is effective for the annual period ending after December 15, 2016, and for annual periods and interim periods thereafter. Early application is permitted.
	In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606). The core principle of this new guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To achieve that core principle, an entity should apply the following steps:
	Step 1: Identify the contract(s) with a customer.
	Step 2: Identify the performance obligations in the contract.
	Step 3: Determine the transaction price.
	Step 4: Allocate the transaction price to the performance obligations in the contract.
	Step 5: Recognize revenue when (or as) the entity satisfies a performance obligation.
	The new guidance also specifies the accounting for some costs to obtain or fulfill a contract with a customer. An entity will be required to disclose sufficient qualitative and quantitative information to enable users of financial statements to understand the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. For calendar-year public entities, the new guidance is effective starting in 2017, and interim periods within that year. Early adoption is not permitted. An entity should apply the amendments in this update using one of the following two methods:
	1	Retrospectively to each prior reporting period presented.
	2	Retrospectively with the cumulative effect of initially applying this update recognized at the date of initial application. If an entity elects this transition method, it also should provide the additional disclosures in reporting periods that include the date of initial application of:
	i.	The amount by which each financial statement line item is affected in the current reporting period by the application of this update as compared to the guidance that was in effect before the change.
	ii.	An explanation of the reasons for significant changes.
	We intend to adopt ASU 2014-09 in our financial statements for the annual period beginning on January 1, 2017. The extent of the impact of adoption of the standard has not yet been determined.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Schedule of Out-of-Period Adjustments	The out-of-period adjustment had the following impact on the consolidated balance sheet and the consolidated statement of operations and comprehensive loss in 2014:
	Increase to balance sheet captions:	(In thousands)
	Other current assets	$	91
	Inventory	2,339
	Property, plant and equipment	7,742
	Other non-current assets	275
	Other current liabilities	8
	Accumulated other comprehensive income	14,281
	Increase (decrease) to statements of operations and comprehensive loss captions:
	Revenues	$	270
	Costs of sales	5,745
	Foreign exchange gain	1,633
	Net loss	3,842
	Foreign currency translation adjustments	(14,281		)
	Comprehensive loss	(10,439		)
	The changes in the presentation of the Condensed Consolidating Balance Sheets at December 31, 2013 and the Condensed Consolidating Statements of Cash Flows for the year ended December 31, 2012 are as follows:
	Condensed Consolidating Balance Sheets	At December 31, 2013
		(In thousands)
	Parent	As reported			Adjustment			Revised
	Investments in consolidated subsidiaries	$	532,767		$	(532,767	)	$	—
	Intercompany accounts receivable	2,001,583			532,767			2,534,350
	Guarantor Subsidiaries							—
	Investments in consolidated subsidiaries	$	121,849		$	(17,522	)	$	104,327
	Additional paid-in capital	149,857			(17,522		)	132,335
	Non-Guarantor Subsidiaries							—
	Intercompany accounts payable	$	2,021		$	780,990		$	783,011
	Additional paid-in capital	1,315,426			(780,990		)	534,436
	Condensed Consolidating Statements of Cash Flows	At December 31, 2012
		(In thousands)
	Parent	As reported			Adjustment			Revised
	Loans to subsidiaries	$	(683,063	)	$	(14,150	)	$	(697,213	)
	Repayments from subsidiaries	87,824			14,150			101,974
	Non-Guarantor Subsidiaries							—
	Borrowing from parent	$	455,551		$	14,150		$	469,701
	Repayments of borrowings to parent	(53,497		)	(14,150		)	(67,647		)

Segment_Information_Tables

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Schedule of segment information
	Year ended December 31, 2014	Resources			Chemicals and Oxides			Magnetic Materials and Alloys			Rare Metals			Corporate and other(a)			Eliminations(b)			Total Molycorp, Inc.
		(In thousands)
	Revenues:
	External	$	14,097		$	159,365		$	222,795		$	79,355					$	—		$	475,612
	Inter-segment	34,093			22,056			7,591			—						(63,740		)	—
	Total revenues	$	48,190		$	181,421		$	230,386		$	79,355					$	(63,740	)	$	475,612
	OIBDA	(146,157		)	(202,588		)	52,966			(442		)
	Depreciation, amortization and accretion	(78,739		)	(17,401		)	(16,956		)	(10,343		)
	Operating (loss) income (c)	$	(224,896	)	$	(219,989	)	$	36,010		$	(10,785	)	$	(33,195	)	$	1,984		$	(450,871	)
	Other expense																			(5,092		)
	Foreign exchange loss, net																			(3,146		)
	Interest expense, net of capitalized interest																			(167,375		)
	Gain on extinguishment of convertible notes, net																			19,719
	Impairment of investment at cost																			$	(12,000	)
	Loss before income taxes and equity earnings																			$	(618,765	)
	Total assets at December 31, 2014	$	1,593,105		$	248,040		$	618,314		$	105,826		$	1,385,265		$	(1,374,564	)	$	2,575,986
	Capital expenditures (d)	$	49,364		$	3,907		$	2,120		$	2,063		$	—		$	—		$	57,454
	Year ended December 31, 2013	Resources			Chemicals and Oxides			Magnetic Materials and Alloys			Rare Metals			Corporate and other (a)			Eliminations(b)			Total Molycorp, Inc.
		(In thousands)
	Revenues:
	External	$	33,621		$	181,815		$	252,713		$	86,241					$	—		$	554,390
	Inter-segment	26,040			37,256			—			—						(63,296		)	—
	Total revenues	$	59,661		$	219,071		$	252,713		$	86,241					$	(63,296	)	$	554,390
	OIBDA	(177,384		)	(65,135		)	50,899			(12,456		)
	Depreciation, amortization and accretion	(46,318		)	(22,754		)	(27,812		)	(8,652		)
	Operating (loss) income (c)	$	(223,702	)	$	(87,889	)	$	23,087		$	(21,108	)	$	(46,126	)	$	(953	)	$	(356,691	)
	Other expense																			1,886
	Foreign exchange loss, net																			(376		)
	Interest expense, net of capitalized interest																			(67,684		)
	Impairment of investment at cost																			(9,411		)
	Loss before income taxes and equity earnings																			$	(432,276	)
	Total assets at December 31, 2013	$	1,791,421		$	485,642		$	590,516		$	82,538		$	1,547,267		$	(1,490,582	)	$	3,006,802
	Capital expenditures (d)	$	231,027		$	6,961		$	3,700		$	7,549		$	250		$	—		$	249,487
	Year ended December 31, 2012	Resources			Chemicals and Oxides			Magnetic Materials and Alloys			Rare Metals (e)			Corporate and other(a)			Eliminations(b)			Total Molycorp, Inc.
		(In thousands)
	Revenues:
	External	$	88,870		$	181,849		$	179,335		$	77,642					$	—		$	527,696
	Inter-segment	7,256			25,717			—			—						(32,973		)	—
	Total revenues	$	96,126		$	207,566		$	179,335		$	77,642					$	(32,973	)	$	527,696
	OIBDA	(56,229		)	(177,949		)	(105,806		)	(12,834		)
	Depreciation, amortization and accretion	(13,991		)	(13,110		)	(19,737		)	(5,837		)
	Operating loss (c)	$	(70,220	)	$	(191,059	)	$	(125,543	)	$	(18,671	)	$	(85,459	)	$	24,803		$	(466,149	)
	Other expense																			(38,798		)
	Foreign exchange gain, net																			2,872
	Interest expense, net of capitalized interest																			(22,116		)
	Loss before income taxes and equity earnings																			$	(524,191	)
	Capital expenditures (d)	$	814,054		$	10,910		$	5,614		$	10,750		$	1,733		$	—		$	843,061
	(a)	Includes business development costs, personnel costs, stock-based compensation, accounting and legal fees, occupancy expense, information technology costs and interest expense.
	(b)	Consists of inter-segment sales and gross profits eliminations as well as eliminations of lower of cost or market adjustments related to inter-segment inventory.
	(c)	Includes impairment of goodwill and other long-lived assets in some segments. See Notes 7 and 9 below for details.
	(d)	On an accrual basis excluding capitalized interest. Interest was no longer capitalized in 2014.
	(e)	Excludes operating results from the Napanee facility, which is treated as a discontinued operation for comparative purposes.
Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas	The geographic distribution of our revenues based on our customers' locations for the years ended December 31, 2014, 2013 and 2012, was as follows:
		Years Ended December 31,
		2014			2013			2012
		(In thousands)
	Asia:
	China	$	162,980		$	199,021		$	118,086
	Japan	100,468			99,952			160,942
	Thailand	19,585			17,129			7,674
	Hong Kong	—			8,815			4,793
	South Korea	14,451			12,418			3,828
	Singapore	150			54			212
	North America	89,769			92,066			103,555
	Europe	86,285			113,549			117,907
	Other	1,924			11,386			10,699
	Total	$	475,612		$	554,390		$	527,696
	Our property, plant and equipment, net carrying amounts by geographic location at December 31, 2014 and 2013 were as follows:
		At December 31,
		2014			2013
		(In thousands)
	North America	$	1,582,291		$	1,627,892
	Europe	68,212			73,674
	China	49,930			53,131
	Thailand	5,457			6,213
	Other Asia	2,080			1,913
	Other	—			51
	Total	$	1,707,970		$	1,762,874

Inventory_Tables

Inventory (Tables)	12 Months Ended
	Dec. 31, 2014
Inventory Disclosure [Abstract]
Schedule of Inventory	At December 31, 2014 and 2013, our inventory consisted of the following:
		December 31,
		2014		2013
		(In thousands)
	Current:
	Concentrate stockpiles	$	—	$	24
	Raw materials	47,796		42,627
	Work in process	24,901		41,962
	Finished goods	67,795		65,662
	Materials and supplies	28,831		21,508
	Total current	$	169,323	$	171,783
	Long-term:
	Concentrate stockpiles	$	—	$	4
	Raw materials	25,127		25,325
	Total long-term	$	25,127	$	25,329
Schedule of Charges to Cost of Sales Based on Normal Production Levels and Write-Down of Inventory	The following table presents charges to costs of sales related to our assessment of normal production levels and write-downs of inventory:
		December 31,
		2014		2013		2012
		(In thousands)
	Abnormal production costs expensed in the period (a)	$	93,917	$	88,070	$	11,982
	Write-down to the lower of cost or market (b)	84,414		100,346		80,939
	Write-downs of stockpile inventory (c)	—		—		2,100
	Total	$	178,331	$	188,416	$	95,021
	(a)	Relates to production costs that would have been inventoriable had we been operating at normal production levels. In all periods presented, the majority of these production costs related to the Resources segment.
	(b)	Attributable to the decline in rare earths prices and low inventory turnover.
	(c)	Adjustments of the estimated REO content in the stockpile at the Resources segment.

Deposits_Tables

Deposits (Tables)	12 Months Ended
	Dec. 31, 2014
Deposits [Abstract]
Schedules of Deposits	We had $31.1 million and $26.0 million in deposits reported as non-current assets at December 31, 2014 and 2013, respectively, which consisted of the following:
		December 31,
		2014		2013
		(In thousands)
	Escrow arrangement with Kern River Gas Transmission Company ("Kern River")	$	20,612	$	20,612
	Construction insurance program	2,710		1,504
	Collateral placed against the surety bonds issued to California state and regional agencies for the closure and reclamation obligations at the Mountain Pass facility, and other deposits	7,756		3,881
	Total	$	31,078	$	25,997

Property_Plant_and_Equipment_n1

Property, Plant and Equipment, net (Tables)	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Schedule of property, plant and equipment	At December 31, 2014 and 2013, our property, plant and equipment consisted of the following:
		December 31,
		2014			2013
		(In thousands)
	Land	$	13,121		$	12,822
	Land improvements (15 to 30 years)	305,119			327,029
	Buildings and improvements (4 to 40 years)	811,418			418,510
	Plant and equipment (2 to 15 years)	623,453			288,603
	Vehicles (7 years)	2,884			2,986
	Computer software (5 years)	12,268			12,424
	Furniture and fixtures (5 years)	1,039			1,044
	Construction in progress (a)	80,699			755,107
	Natural gas delivery facility under capital lease (10 years)	15,658			15,658
	Mining equipment under capital lease (7 years)	10,982			7,370
	Mineral properties (Note 8)	23,669			23,999
	Property, plant and equipment at cost	1,900,310			1,865,552
	Less accumulated depreciation	(192,340		)	(102,678		)
	Property, plant and equipment, net	$	1,707,970		$	1,762,874
	(a)	Primarily related to expenditures at the Molycorp Mountain Pass facility

Goodwill_and_Other_Intangible_1

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	Changes in the carrying amount of goodwill by reportable segment during the years ended December 31, 2014, 2013 and 2012, were as follows:
		Chemicals and Oxides				Magnetic Materials and Alloys				Rare Metals				Total
		(In thousands)
	31-Dec-11	$	728			$	1,977			$	727			$	3,432
	Goodwill acquired	285,633				213,525				27,046				526,204
	Impairment	(161,132		)		(112,694		)		(16,068		)		(289,894		)
	31-Dec-12	125,229				102,808				11,705				239,742
	Impairment	—				—				(10,992		)		(10,992		)
	31-Dec-13	125,229				102,808				713				228,750
	Impairment	(125,229		)		—				(713		)		(125,942		)
	31-Dec-14	$	—			$	102,808			$	—			$	102,808
Schedule of amortizable intangible assets	At December 31, 2014 and 2013, our intangible assets, other than goodwill, consisted of the following:
		Customer relationships			Rare earths quotas			Patents			Trade names			Land use rights			Other		Total
	Gross carrying amount	(In thousands)
	31-Dec-13	$	344,580		$	—		$	152		$	15,586		$	3,568		$	4,420	$	368,306
	Additions	—			—			—			—			—			37		37
	Foreign currency translation adjustment	177			—			—			—			—			—		177
	Impairment	(121,057		)	—			—			—			(368		)	—		(121,425		)
	31-Dec-14	$	223,700		$	—		$	152		$	15,586		$	3,200		$	4,457	$	247,095
	Accumulated Amortization
	31-Dec-13	$	35,980		$	—		$	27		$	343		$	227		$	862	$	37,439
	Amortization	23,019			—			125			66			77			617		23,904
	Impairment	(30,119		)	—			—			—			—			—		(30,119		)
	31-Dec-14	28,880			—			152			409			304			1,479		31,224
	Net book value	$	194,820		$	—		$	—		$	15,177		$	2,896		$	2,978	$	215,871
		Customer relationships			Rare earths quotas			Patents			Trade names			Land use rights			Other		Total
	Gross carrying amount	(In thousands)
	31-Dec-12	$	344,774		$	78,300		$	33,252		$	15,586		$	3,568		$	4,420	$	479,900
	Additions	48			—			—			—			—			—		48
	Foreign currency translation adjustment	(242		)	—			—			—			—			—		(242		)
	Impairment	—			(78,300		)	(33,100		)	—			—			—		(111,400		)
	31-Dec-13	$	344,580		$	—		$	152		$	15,586		$	3,568		$	4,420	$	368,306
	Accumulated Amortization
	31-Dec-12	$	14,095		$	4,035		$	9,365		$	1,152		$	66		$	249	$	28,962
	Amortization	22,145			7,018			13,554			65			161			613		43,556
	Adjustments	(260		)	—			—			(874		)	—			—		(1,134		)
	Impairment	—			(11,053		)	(22,892		)	—			—			—		(33,945		)
	31-Dec-13	35,980			—			27			343			227			862		37,439
	Net book value	$	308,600		$	—		$	125		$	15,243		$	3,341		$	3,558	$	330,867
Schedule of Expected Amortization Expense	Amortization expense on all other intangible assets for the next five years and thereafter is expected to be as follows:
		(In thousands)
	2015	$	16,441
	2016	16,441
	2017	16,441
	2018	16,277
	2019	16,277
	Thereafter	119,194

Investments_Tables

Investments (Tables)	12 Months Ended
	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Schedule of Equity Method Investments	The following table provides a reconciliation of the carrying amount of our investments at December 31, 2014 and 2013:
		Boulder Wind Power, Inc.			IMJ			Keli			Ingal Stade			Other investments				Total
		(In thousands)
	31-Dec-12	$	20,000		$	25,193		$	11,000		$	5,015		$	2,828			$	64,036
	Additions	—			3,419			—			—			—				3,419
	Equity loss	n/a			(6,529		)	(2,600		)	(40		)	—				(9,169		)
	Impairment	(8,000		)	—			—			—			(1,411		)	(a)	(9,411		)
	31-Dec-13	12,000			22,083			8,400			4,975			1,417				48,875
	Adjustment to investments classification	—			51			(1,240		)	(38		)	1,227				—
	Additions	—			—			—			—			703				703
	Dividends	—			—			(2,014		)	—			—				(2,014		)
	Equity (loss) income	n/a			(6,541		)	(635		)	(51		)	158				(7,069		)
	Impairment	(12,000		)	(14,808		)	—			(4,886		)	—				(31,694		)
	31-Dec-14	$	—		$	785		$	4,511		$	—		$	3,505			$	8,801
	(a) The impairment charge in 2013 relates to the equity interest in Atlantic Metals & Alloys, LLC.
Schedule of Cost Method Investments	The following table provides a reconciliation of the carrying amount of our investments at December 31, 2014 and 2013:
		Boulder Wind Power, Inc.			IMJ			Keli			Ingal Stade			Other investments				Total
		(In thousands)
	31-Dec-12	$	20,000		$	25,193		$	11,000		$	5,015		$	2,828			$	64,036
	Additions	—			3,419			—			—			—				3,419
	Equity loss	n/a			(6,529		)	(2,600		)	(40		)	—				(9,169		)
	Impairment	(8,000		)	—			—			—			(1,411		)	(a)	(9,411		)
	31-Dec-13	12,000			22,083			8,400			4,975			1,417				48,875
	Adjustment to investments classification	—			51			(1,240		)	(38		)	1,227				—
	Additions	—			—			—			—			703				703
	Dividends	—			—			(2,014		)	—			—				(2,014		)
	Equity (loss) income	n/a			(6,541		)	(635		)	(51		)	158				(7,069		)
	Impairment	(12,000		)	(14,808		)	—			(4,886		)	—				(31,694		)
	31-Dec-14	$	—		$	785		$	4,511		$	—		$	3,505			$	8,801
	(a) The impairment charge in 2013 relates to the equity interest in Atlantic Metals & Alloys, LLC.

Acquisitions_Tables

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
Summarizes the purchase prices and opening balance sheets for the acquisitions	The following table summarizes the purchase consideration as well as the estimated fair value of the assets acquired and liabilities assumed in the Molycorp Canada acquisition:
		Preliminary Allocation of Consideration Transferred as of December 31, 2012			Measurement Period Adjustments			Final Allocation of Consideration 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
	Intangible assets	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	The following unaudited pro forma financial information provides what our consolidated revenues, net income (loss) and basic earnings per share would have been had the acquisition closed on January 1, 2012:
	(In thousands, except per share amounts)	Revenues				Net income (loss)				Net income (loss)			EPS Basic
										attributable to Molycorp
	Unaudited pro forma January 1, 2012 to December 31, 2012 (combined entity)	$	863,728			$	(463,716	)		$	(473,249	)	$	(4.53	)
Schedule of Transaction Costs	For the year ended December 31, 2012, we recognized approximately $62.0 million of transaction costs related to the Molycorp Canada acquisition in our consolidated statement of operations and comprehensive loss as follows:
		(In thousands)
	Corporate development:
	Legal, accounting and advisory fees	$	16,498
	Other expenses:
	Contingent forward contract loss	$	37,589
	Interest expense:
	Bridge loan fee	$	7,937

Accrued_Expenses_Tables

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2014
Payables and Accruals [Abstract]
Schedule of accrued expenses	Accrued expenses at December 31, 2014 and 2013 consisted of the following:
		December 31,
		2014		2013
		(In thousands)
	Defined contribution plan	$	613	$	1,921
	Professional fees	1,955		135
	Accrued payroll and related benefits	7,010		5,739
	Sales and use tax	2,339		3,354
	Bonus accrual	5,109		4,449
	Interest payable	18,300		18,158
	Advance from customer	130		600
	Withholding taxes	376		2,563
	Amount payable to noncontrolling interest	2,929		—
	Other accrued expenses	13,205		11,582
	Total accrued expenses	$	51,966	$	48,501

Asset_Retirement_Obligation_Ta

Asset Retirement Obligation (Tables)	12 Months Ended
	Dec. 31, 2014
Asset Retirement Obligation Disclosure [Abstract]
Schedule of activity in asset retirement obligation	The following table presents the activity of our ARO for the years ended December 31, 2014 and 2013:
		December 31,
		2014			2013
		(In thousands)
	Balance at beginning of period	$	17,583		$	22,125
	Obligations settled	(1,549		)	(3,849		)
	Accretion expense	1,153			1,328
	Revisions in estimated cash flows	—			(3,793		)
	Loss on settlement	932			1,772
	Balance at end of period	$	18,119		$	17,583

Debt_and_Capital_Lease_Obligat1

Debt and Capital Lease Obligations (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Summary of the current and non-current portions of the debt outstanding	The following table provides a summary of the current and non-current portions of our debt and capital lease obligations at December 31, 2014 and 2013:
		December 31,
		2014								2013
		Current				Non-Current				Current				Non-Current
		(In thousands)
	Bank loans due February 2015 - June 2017	$	9,326			$	91			$	14,128			$	2,699
	3.25% Convertible Notes, net of discount, due June 2016	—				193,549				—				207,028
	6.00% Convertible Notes, net of discount, due September 2017	—				335,969				—				346,708
	5.00% Debentures, net of discount, due December 2017	—				2,075				—				2,493
	5.50% Convertible Notes, net of discount, due February 2018	—				143,581				—				148,198
	12.00% Term Loans, due September 2019	—				98,812				—				—
	12.00% Equipment Financing, due September 2019	—				127,594				—				—
	10% Senior Secured Notes, net of discount, due June 2020	—				638,899				—				637,435
	Total debt	$	9,326			$	1,540,570			$	14,128			$	1,344,561
	Capital lease obligations	3,234				19,211				2,234				19,355
	Total debt and capital lease obligations	$	12,560			$	1,559,781			$	16,362			$	1,363,916
Schedule of Convertible Debt	A reconciliation of the principal amount to the net carrying amount for each of our Convertible Notes and our 10% Senior Secured Notes at December 31, 2014 and 2013 is as follows:
		3.25% Convertible Notes							6.00% Convertible Notes							5.50% Convertible Notes						10% Senior Notes
		At December 31,
		2014			2013				2014			2013				2014			2013			2014			2013
		(In thousands)
	Principal amount	$	206,505		$	230,000			$	383,000		$	414,000			$	161,500		$	172,500		$	650,000		$	650,000
	Unamortized debt discount	(12,956		)	(22,972		)		(47,031		)	(67,292		)		(17,919		)	(24,302		)	(11,101		)	(12,565		)
	Net carrying amount	$	193,549		$	207,028			$	335,969		$	346,708			$	143,581		$	148,198		$	638,899		$	637,435
	Interest cost incurred on each instrument in the table immediately above was as follows for the years ended December 31, 2014, 2013 and 2012:
		Year Ended December 31,
		2014				2013				2012
		(In thousands)
	3.25% Convertible Notes	$	15,553			$	15,839			$	15,312
	6.00% Convertible Notes	41,070				39,779				17,457
	5.50% Convertible Notes	14,578				13,107				n/a
	10% Senior Notes	66,606				66,323				40,070
Schedule of Maturities of Long-term Debt	Our scheduled minimum debt repayments, excluding capital lease obligations, were as follows at December 31, 2014:
	Debt maturities, excluding capital leases	(In thousands)
	2015	$	9,326
	2016	206,565
	2017	385,106
	2018	161,500
	2019	321,154
	Thereafter	650,000
	Total	$	1,733,651
Reconciliation of Principal to Net Carrying Amount of Long-term Debt	The following table presents a reconciliation of the principal amount to the net carrying amount of, and interest cost for, the Term Loans and the Equipment Financing at December 31, 2014:
		12.00% Term Loans				12.00% Equipment Financing
		(In thousands)
	Principal amount (a)	$	111,858			$	141,993
	Unamortized debt discount	(13,046		)		(14,399		)
	Net carrying amount	$	98,812			$	127,594
	Cash interest	$	6,264			$	2,082
	PIK interest	1,691				2,160
	Total interest cost	$	7,955			$	4,242
Schedule of Future Minimum Lease Payments for Capital Leases	Those agreements contain purchase options at the end of the lease term and are generally at market interest rates. At December 31, 2014, total future minimum payments on our capital leases were as follows:
	Capital Leases	(In thousands)
	2015	$	8,276
	2016	8,276
	2017	7,159
	2018	5,769
	2019	5,488
	Thereafter	12,706
	Total	$	47,674
	Imputed interest included in total future minimum lease payments at December 31, 2014	$	22,655

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense	Income tax expense consisted of the following for the years ended December 31, 2014, 2013 and 2012:
		Years Ended December 31,
		2014			2013			2012
		(In thousands)
	Current
	Federal	$	—		$	(2,581	)	$	(22,418	)
	Foreign	16,532			(1,018		)	8,994
	State	(130		)	792			(4,197		)
	Total current	16,402			(2,807		)	(17,621		)
	Deferred
	Federal	(8,111		)	(43,479		)	(20,786		)
	Foreign	(29,366		)	(16,517		)	(11,777		)
	State	(1,519		)	(8,140		)	(3,891		)
	Total deferred	(38,996		)	(68,136		)	(36,454		)
	Total tax benefit	$	(22,594	)	$	(70,943	)	$	(54,075	)
Schedule of Income before Income Tax, Domestic and Foreign	The components of our losses before income taxes and equity earnings, by tax jurisdiction, were as follows for the years ended December 31, 2014, 2013 and 2012:
		Years Ended December 31,
		2014			2013			2012
		(In thousands)
	United States	$	(415,381	)	$	(286,818	)	$	(161,129	)
	Foreign	(203,384		)	(145,458		)	(363,062		)
	Total	$	(618,765	)	$	(432,276	)	$	(524,191	)
Schedule of Effective Income Tax Rate Reconciliation	A reconciliation of the statutory federal income tax rate of 35% to our effective income tax rate is as follows for the years ended December 31, 2014, 2013 and 2012:
		Years Ended December 31,
		2014			2013			2012
		(In thousands)
	Federal tax computed at the statutory rate	$	(216,568	)	$	(151,297	)	$	(184,075	)
	State taxes, net of federal benefit	(16,609		)	(10,329		)	(5,970		)
	Change in valuation allowance	148,187			85,881			19,515
	Impairment of goodwill and other long-lived assets	48,250			7,458			103,563
	Changes related to uncertain tax positions	1,220			(5,153		)	(14,176		)
	Federal and State tax credits	—			2,946			(6,817		)
	Foreign income tax rate differential	12,956			24,315			18,682
	Foreign translation adjustments	(11,968		)	(7,744		)	—
	Change in applicable law	—			(5,884		)	—
	Other items, net	11,938			(11,136		)	15,203
	Income tax benefit	$	(22,594	)	$	(70,943	)	$	(54,075	)
Schedule of Deferred Tax Assets and Liabilities	The tax effect of temporary differences and our net operating losses, which give rise to deferred tax assets and liabilities, consisted of the following at December 31, 2014 and 2013:
		At December 31,
		2014			2013
		(In thousands)
	Deferred tax assets:
	Current:
	Inventory	$	30,487		$	2,570
	Other	1,499			2,605
	Total current	31,986			5,175
	Non-current:
	Asset retirement obligation	3,705			—
	Mineral resources	16,832			16,886
	Property, plant and equipment and intangible assets	3,451			21,044
	Stock compensation	2,805			1,964
	Net operating losses	255,588			144,366
	Research and energy tax credits and expenditures	6,141			6,233
	Alternative Minimum Tax Credit	2,216			2,216
	Unrealized foreign exchange	17,380			5,664
	Investments	—			3,120
	Other	5,675			4,107
	Total non-current	313,793			205,600
	Deferred tax liabilities:
	Current
	Inventory	—			1,312
	Other	1,680			1,423
	Total current	1,680			2,735
	Non-current:
	Asset retirement obligation	—			1,190
	Foreign subsidiary earnings and withholding taxes	10,423			14,804
	Property, plant, equipment and intangible assets	100,076			125,527
	Convertible debt (Notes), share lending and other financing arrangements	35,722			44,275
	Other	83			302
	Total non-current	146,304			186,098
	Net deferred taxes, before valuation allowance	197,795			21,942
	Valuation allowance	(252,291		)	(107,358		)
	Total deferred tax	$	(54,496	)	$	(85,416	)
Schedule of Income Tax Contingencies	A reconciliation of the beginning and ending amount of our gross unrecognized tax benefits is as follows:
		Years Ended December 31,
		2014			2013			2012
		(In thousands)
	Balance, beginning of year	$	1,066		$	6,219		$	519
	Tax position related to current year:
	Additions	1,220			—			4,737
	Tax positions related to prior years:
	Additions	—			—			16,109
	Settlements	—			(4,737		)	(13,740		)
	Statute of limitations closures	—			(416		)	(1,406		)
	Balance, end of year	$	2,286		$	1,066		$	6,219

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques	The fair value of the Warrants, which initially was estimated at approximately $3.5 million, was determined using an option-pricing model with the following inputs:
		Penny Warrants			Strike Warrants
	Term (years)	5			5
	Stock price	$	1.55		$	1.55
	Strike price	$	0.01		$	2.04
	Risk-free interest rate	1.79		%	1.79		%
	Volatility	82.6		%	49.9		%
	Dividend yield	—		%	—		%
Accounting Changes and Error Corrections	The out-of-period adjustment had the following impact on the consolidated balance sheet and the consolidated statement of operations and comprehensive loss in 2014:
	Increase to balance sheet captions:	(In thousands)
	Other non-current assets	$	16,381
	Property, plant and equipment, net	3,378
	Additional paid-in capital	15,062
	Increase to statements of operations and comprehensive loss captions:
	Interest expense, net of capitalized interest	4,933
	Income tax benefit	9,630
Schedule of Share-Lending Arrangements	The following table provides certain other information on our share-lending arrangements as of December 31, 2014:
		2012 Borrowed Shares			2013 Borrowed Shares			Total
		(In thousands)
	Fair value	$	3,329		$	1,890		$	5,219
	Unamortized issuance cost	9,694			4,174			13,868
Deferred Finance Costs, Own-share Lending Arrangement, Issuance Costs	The amount of non-cash interest cost recognized relating to the amortization of the issuance cost associated with the combined share-lending arrangements was as follows for the year ended December 31, 2014:
		(In thousands)
	Interest cost expensed	$	7,445
	Interest cost capitalized	3,378
	Total	$	10,823
Schedule of Accumulated Other Comprehensive Income (Loss)	The following table provides the changes in Accumulated Other Comprehensive Income (Loss) (“AOCI”) for the years ended December 31, 2014, 2013 and 2012:
		Foreign currency translation adjustments			Postretirement benefit liability			Accumulated other comprehensive loss
		(In thousands)
	Balance at December 31, 2011	$	(8,481	)	$	—		$	(8,481	)
	Change in other comprehensive loss before reclassifications	248			(1,200		)	(952		)
	Net income (loss) reclassified from AOCI	—			—			—
	Balance at December 31, 2012	(8,233		)	(1,200		)	(9,433		)
	Change in other comprehensive loss before reclassifications	1,623			1,359			2,982
	Net income (loss) reclassified from AOCI	—			—			—
	Balance at December 31, 2013	(6,610		)	159			(6,451		)
	Change in other comprehensive loss before reclassifications	4,271			(1,143		)	3,128
	Net income (loss) reclassified from AOCI	—			—			—
	Balance at December 31, 2014	$	(2,339	)	$	(984	)	$	(3,323	)

Loss_per_Share_Tables

Loss per Share (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Schedule of loss per share, basic and diluted
		Years Ended December 31,
		2014			2013			2012
		(In thousands, except share and per share amounts)
	Net loss attributable to Molycorp stockholders	$	(604,934	)	$	(374,383	)	$	(481,169	)
	Dividends on Convertible Preferred Stock	(2,846		)	(11,385		)	(11,385		)
	Loss attributable to common stockholders	(607,780		)	(385,768		)	(492,554		)
	Continuing operations	$	(607,780	)	$	(379,341	)	$	(490,817	)
	Discontinued operations	—			(6,427		)	(1,737		)
		$	(607,780	)	$	(385,768	)	$	(492,554	)
	Weighted average common shares outstanding—basic	224,978,752			174,528,717			107,064,892
	Basic loss per share from:
	Continuing operations	$	(2.70	)	$	(2.17	)	$	(4.58	)
	Discontinued operations	—			(0.04		)	(0.02		)
		$	(2.70	)	$	(2.21	)	$	(4.60	)
	Weighted average common shares outstanding—diluted	224,978,752			174,528,717			107,064,892
	Diluted loss per share from:
	Continuing operations	$	(2.70	)	$	(2.17	)	$	(4.58	)
	Discontinued operations	—			(0.04		)	(0.02		)
		$	(2.70	)	$	(2.21	)	$	(4.60	)

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs	We recognized total annual stock-based compensation expenses and related income tax benefit as follows:
		2014				2013		2012
		(In thousands)
	Stock-based compensation expense	$	5,261			$	5,392	$	3,434
PBRSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Summary of Activity Related to Stock-based Awards	The following tables summarize the activity related to restricted stock-based awards for the year ended December 31, 2014:
	PBRSUs	Number of			Weighted Average
		Shares			Grant-Date
					Price
	Unvested at December 31, 2013	697,797			$	7.45
	Granted	975,505			4.22
	Forfeited	(41,240	)		6.66
	Vested	(18,246	)		30.33
	Unvested at December 31, 2014	1,613,816			5.28
Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity	Additional annual information for restricted stock-based awards is included in the following tables:
	Weighted average grant-date fair value of shares granted	2014		2013		2012
		(In thousands)
	PBRSUs	$4,117		$6,139		$1,382
	RSUs	4,499		7,060		5,540
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Summary of Activity Related to Stock-based Awards
	RSUs	Number of			Weighted Average
		Shares			Grant-Date
					Price
	Unvested at December 31, 2013	1,076,385			$	9.81
	Granted	1,165,497			3.86
	Forfeited	(71,399	)		8.71
	Vested	(70,998	)		22.98
	Unvested at December 31, 2014	2,099,485			6.1
	RSAs	Number of			Weighted Average
		Shares			Grant-Date
					Price
	Unvested at December 31, 2013	6,326			$	55.05
	Granted	—			—
	Forfeited	—			—
	Vested	—			—
	Unvested at December 31, 2014	6,326			55.05
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Summary of Activity Related to Stock-based Awards
	RSAs	Number of			Weighted Average
		Shares			Grant-Date
					Price
	Unvested at December 31, 2013	6,326			$	55.05
	Granted	—			—
	Forfeited	—			—
	Vested	—			—
	Unvested at December 31, 2014	6,326			55.05

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2014

Commitments and Contingencies Disclosure [Abstract]

Schedule of future minimum rental payments for operating leases

Remaining annual minimum payments under these leases at December 31, 2014 were as follows:

Total

Less Than

1 - 3 Years

4 - 5 Years

More Than

1 Year

5 Years

(In thousands)

Operating lease obligations

$

6,661

$

2,380

$

3,012

$

508

$

761

Schedule of minimum payments for purchase obligations

Future payments for all purchase commitments at December 31, 2014 were as follows:

Total

Less Than

1 - 3 Years

4 - 5 Years

More Than

1 Year

5 Years

(In thousands)

Purchase obligations and other commitments

$

8,187

$

—

8,187

—

—

Net_Change_in_Operating_Assets1

Net Change in Operating Assets and Liabilities (Tables)	12 Months Ended
	Dec. 31, 2014
Net Change in Operating Assets and Liabilities
Schedule of changes in operating assets and liabilities, net of the effects of acquisitions and dispositions	Net change in our operating assets and liabilities, net of the effects of acquisitions and dispositions, consisted of the following in each of the three-year period ended December 31, 2014:
		Years Ended December 31,
		2014			2013			2012
		(In thousands)
	Decrease (increase) in operating assets:
	Trade accounts receivable	$	17,169		$	(8,986	)	$	124,983
	Inventory	(82,390		)	15,649			(46,126		)
	Prepaid expenses and other assets	(4,299		)	(5,728		)	33,520
	Increase (decrease) in operating liabilities:
	Accounts payable	(14,028		)	(24,177		)	(34,972		)
	Income tax payable	2,271			18,966			(40,263		)
	Interest payable	30,181			(39,120		)	(40,792		)
	Asset retirement obligation	(1,606		)	(7,642		)	(1,467		)
	Accrued expenses	3,918			(13,681		)	(54,763		)
		$	(48,784	)	$	(64,719	)	$	(59,880	)

Supplemental_Cash_Flow_Informa1

Supplemental Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2014
Supplemental Cash Flow Elements [Abstract]
Summary of Supplemental Cash Flow Information
		Years Ended December 31,
		2014		2013			2012
		(In thousands)
	Net cash paid for:
	Income taxes	$	13,976	$	(13,429	)	$	178
	Interest, net of capitalized interest	112,575		32,833			8,942
	Non-cash financing activities and investing activities:
	Change in accrued capital expenditures	28,501		58,673			52,189
	Conversion of debt securities to equity securities	38,000		18			4,527
	Acquisition of exploration rights	—		—			8,000
	Debt assumed from business acquisitions	—		—			40,691
	Issuance of common stock for business acquisitions	—		—			284,100
	Fixed assets additions under capital lease	3,612		7,370			15,658

Fair_Value_of_Financial_Instru1

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value Measurements, Recurring and Nonrecurring	Our assets and liabilities measured at fair value on a recurring basis were as follows at December 31, 2014 and 2013:
		31-Dec-14
		Quoted Prices in Active Markets for Identical Assets/Liabilities		Significant Other Observable Inputs		Significant Unobservable Inputs
		(Level 1)		(Level 2)		(Level 3)
		(In thousands)
	Assets:
	Cash equivalents	$	57,309	—		—
	Liabilities:
	Derivative liabilities:
	Springing Maturity on Term Loans	—		—		$	7,292
	Strike Warrants	—		—		1,769
	Share Purchase Agreement	—		—		6,165
		31-Dec-13
		Quoted Prices in Active Markets for Identical Assets/Liabilities		Significant Other Observable Inputs		Significant Unobservable Inputs
		(Level 1)		(Level 2)		(Level 3)
		(In thousands)
	Assets:
	Cash equivalents	$	179,052	—		—
	Liabilities:
	Derivative liability - Share Purchase Agreement	—		—		$	6,089
Fair Value, by Balance Sheet Grouping	The following table presents the fair value of publicly traded financial liabilities we report at their carrying amount:
		December 31,
		2014					2013
		Carrying Amount		Fair Value			Carrying Amount		Fair Value
		(In thousands)
	3.25% Convertible Notes due June 2016	$	193,549	$	88,281		$	207,028	$	161,771
	6.00% Convertible Notes due September 2017	335,969		107,240			346,708		312,570
	5.50% Convertible Notes due February 2018	143,581		46,028			148,198		164,015
	10% Senior Secured Notes due June 2020	638,899		357,500			637,435		646,750
	Total	$	1,311,998	$	599,049		$	1,339,369	$	1,285,106

Subsidiary_Guarantor_Financial1

Subsidiary Guarantor Financial Information (Tables)	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Condensed Balance Sheet
		At December 31, 2014
		(In thousands)
	Condensed Consolidating Balance Sheets	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations			Molycorp, Inc. consolidated
	Current assets:
	Cash and cash equivalents	$	98,650		$	5,329		$	107,706		$	—		$	211,685
	Trade accounts receivable, net	—			1,924			42,651			—			44,575
	Inventory	—			36,956			132,367			—			169,323
	Prepaid expenses and other current assets	—			9,673			19,659			—			29,332
	Total current assets	98,650			53,882			302,383			—			454,915
	Non-current assets:
	Deposits	1,756			29,322			—			—			31,078
	Property, plant and equipment, net	—			1,575,670			132,300			—			1,707,970
	Inventory	—			25,127			—			—			25,127
	Intangible assets, net	—			377			215,494			—			215,871
	Investments	—			785			8,016			—			8,801
	Goodwill	—			—			102,808			—			102,808
	Investments in consolidated subsidiaries	—			91,672			—			(91,672		)	—
	Intercompany accounts receivable	2,063,568			—			—			(2,063,568		)	—
	Other non-current assets	16,421			7,792			5,203			—			29,416
	Total non-current assets	2,081,745			1,730,745			463,821			(2,155,240		)	2,121,071
	Total assets	$	2,180,395		$	1,784,627		$	766,204		$	(2,155,240	)	$	2,575,986
	Current liabilities:
	Trade accounts payable	$	—		$	14,641		$	26,201		$	—		$	40,842
	Accrued expenses	17,324			16,256			18,386			—			51,966
	Debt and capital lease obligations	—			3,234			9,326			—			12,560
	Other current liabilities	—			263			4,423			—			4,686
	Total current liabilities	17,324			34,394			58,336			—			110,054
	Non-current liabilities:
	Asset retirement obligation	—			17,799			—			—			17,799
	Deferred tax liabilities	—			—			63,802			—			63,802
	Debt and capital lease obligations	1,357,003			146,805			55,973			—			1,559,781
	Intercompany accounts payable	—			2,134,041			658,986			(2,793,027		)	—
	Other non-current liabilities	9,061			1,424			9,762			—			20,247
	Total non-current liabilities	1,366,064			2,300,069			788,523			(2,793,027		)	1,661,629
	Total liabilities	$	1,383,388		$	2,334,463		$	846,859		$	(2,793,027	)	$	1,771,683
	Stockholders’ equity:
	Common stock	260			—			—			—			260
	Additional paid-in capital	2,245,478			132,335			534,440			(666,775		)	2,245,478
	Accumulated other comprehensive loss	(3,323		)	—			(3,323		)	3,323			(3,323		)
	Accumulated deficit	(1,445,408		)	(682,171		)	(619,068		)	1,301,239			(1,445,408		)
	Total Molycorp stockholders’ equity	797,007			(549,836		)	(87,951		)	637,787			797,007
	Noncontrolling interests	—			—			7,296			—			7,296
	Total stockholders’ equity	797,007			(549,836		)	(80,655		)	637,787			804,303
	Total liabilities and stockholders’ equity	$	2,180,395		$	1,784,627		$	766,204		$	(2,155,240	)	$	2,575,986
		At December 31, 2013
		(In thousands)
	Condensed Consolidating Balance Sheets	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations			Molycorp, Inc. consolidated
	Current assets:
	Cash and cash equivalents	$	169,145		$	6,467		$	138,705		$	—		$	314,317
	Trade accounts receivable, net	—			4,990			56,767			—			61,757
	Inventory	—			32,307			139,476			—			171,783
	Prepaid expenses and other current assets	—			15,833			13,377			—			29,210
	Total current assets	169,145			59,597			348,325			—			577,067
	Non-current assets:
	Deposits	1,754			24,243			—			—			25,997
	Property, plant and equipment, net	—			1,620,851			142,023			—			1,762,874
	Inventory	—			25,329			—			—			25,329
	Intangible assets, net	—			442			330,425			—			330,867
	Investments	—			34,134			14,741			—			48,875
	Goodwill	—			—			228,750			—			228,750
	Investments in consolidated subsidiaries	—			104,327			—			(104,327		)	—
	Intercompany accounts receivable	2,534,350			—			—			(2,534,350		)	—
	Other non-current assets	—			771			6,272			—			7,043
Total non-current assets	2,536,104			1,810,097			722,211			(2,638,677		)	2,429,735
Total assets	$	2,705,249		$	1,869,694		$	1,070,536		$	(2,638,677	)	$	3,006,802
Current liabilities:
Trade accounts payable	$	—		$	49,702		$	34,747		$	—		$	84,449
Accrued expenses	18,158			13,782			16,561			—			48,501
Debt and capital lease obligations	—			2,234			14,128			—			16,362
Other current liabilities	—			617			3,446			—			4,063
Total current liabilities	18,158			66,335			68,882			—			153,375
Non-current liabilities:
Asset retirement obligation	—			16,966			—			—			16,966
Deferred tax liabilities	—			—			85,481			—			85,481
Debt and capital lease obligations	1,339,368			19,355			5,193			—			1,363,916
Intercompany accounts payable	—			1,999,562			783,011			(2,782,573		)	—
Other non-current liabilities	—			1,393			8,609			—			10,002
Total non-current liabilities	1,339,368			2,037,276			882,294			(2,782,573		)	1,476,365
Total liabilities	$	1,357,526		$	2,103,611		$	951,176		$	(2,782,573	)	$	1,629,740
Stockholders’ equity:
Common stock	241			—			—			—			241
Preferred stock	2			—			—			—			2
Additional paid-in capital	2,194,405			132,335			534,436			(666,771		)	2,194,405
Accumulated other comprehensive loss	(6,451		)	—			(6,451		)	6,451			(6,451		)
Accumulated deficit	(840,474		)	(366,252		)	(437,964		)	804,216			(840,474		)
Total Molycorp stockholders’ equity	1,347,723			(233,917		)	90,021			143,896			1,347,723
Noncontrolling interests	—			—			29,339			—			29,339
Total stockholders’ equity	1,347,723			(233,917		)	119,360			143,896			1,377,062
Total liabilities and stockholders’ equity	$	2,705,249		$	1,869,694		$	1,070,536		$	(2,638,677	)	$	3,006,802
Schedule of Condensed Income Statement and Comprehensive Income
		Year Ended December 31, 2014
		(In thousands)
	Condensed Consolidating Statements of Operations and Comprehensive Income	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations			Molycorp, Inc. consolidated
	Revenues	$	—		$	60,795		$	452,654		$	(37,837	)	$	475,612
	Costs of sales:
	Costs excluding depreciation and amortization	—			(181,599		)	(337,655		)	37,837			(481,417		)
	Depreciation and amortization	—			(74,119		)	(19,663		)	—			(93,782		)
	Gross (loss) profit	—			(194,923		)	95,336			—			(99,587		)
	Operating expenses:
	Selling, general and administrative	(425		)	(36,768		)	(37,297		)	—			(74,490		)
	Depreciation, amortization and accretion	—			(4,946		)	(24,933		)	—			(29,879		)
	Research and development	—			(526		)	(14,739		)	—			(15,265		)
	Impairment of goodwill and other long-lived assets	—			(13,831		)	(217,819		)	—			(231,650		)
	Operating loss	(425		)	(250,994		)	(199,452		)	—			(450,871		)
	Other (expense) income:
	Other (expense) income	44			(1,853		)	(3,283		)	—			(5,092		)
	Foreign exchange (loss) gain, net	(35,914		)	5			32,763			—			(3,146		)
	Interest expense, net of capitalized interest	(152,144		)	(14,897		)	(334		)	—			(167,375		)
	Gain on extinguishment of convertible notes	19,719			—			—			—			19,719
	Impairment of investment	—			(12,000		)	—			—			(12,000		)
	Interest income (expense) from intercompany notes	38,525			(2,175		)	(36,350		)	—			—
	Equity loss from consolidated subsidiaries	(484,369		)	(12,655		)	—			497,024			—
		(614,139		)	(43,575		)	(7,204		)	497,024			(167,894		)
	Loss from continuing operations before income taxes and equity earnings	(614,564		)	(294,569		)	(206,656		)	497,024			(618,765		)
	Income tax benefit	9,630			—			12,964			—			22,594
	Equity in loss of affiliates	—			(21,350		)	(5,413		)	—			(26,763		)
	Net loss	(604,934		)	(315,919		)	(199,105		)	497,024			(622,934		)
	Net income attributable to noncontrolling interest	—			—			18,000			—			18,000
	Net loss attributable to Molycorp stockholders	$	(604,934	)	$	(315,919	)	$	(181,105	)	$	497,024		$	(604,934	)
	Net loss	$	(604,934	)	$	(315,919	)	$	(199,105	)	$	497,024		$	(622,934	)
	Other comprehensive income:
	Foreign currency translation adjustments	$	—		$	—		$	4,271		$	—		$	4,271
	Actuarial loss	—			—			(1,143		)	—			(1,143		)
	Comprehensive loss	$	(604,934	)	$	(315,919	)	$	(195,977	)	$	497,024		$	(619,806	)
	Comprehensive loss attributable to:
	Molycorp stockholders	(604,934		)	(315,919		)	(177,977		)	497,024			(601,806		)
	Noncontrolling interest	—			—			(18,000		)	—			(18,000		)
		$	(604,934	)	$	(315,919	)	$	(195,977	)	$	497,024		$	(619,806	)
		Year Ended December 31, 2013
		(In thousands)
	Condensed Consolidating Statements of Operations and Comprehensive Income	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations			Molycorp, Inc. consolidated
	Revenues	$	—		$	88,266		$	517,202		$	(51,078	)	$	554,390
	Costs of sales:
	Costs excluding depreciation and amortization	—			(200,650		)	(404,259		)	51,078			(553,831		)
	Depreciation and amortization	—			(40,220		)	(27,507		)	—			(67,727		)
	Gross (loss) profit	—			(152,604		)	85,436			—			(67,168		)
	Operating expenses:
	Selling, general and administrative	(190		)	(66,132		)	(40,847		)	—			(107,169		)
	Corporate development	—			(247		)	—			—			(247		)
	Depreciation, amortization and accretion	—			(6,424		)	(31,613		)	—			(38,037		)
	Research and development	—			(5,069		)	(18,103		)	—			(23,172		)
	Impairment of goodwill and other long-lived assets	—			(14,250		)	(106,648		)	—			(120,898		)
	Operating loss	(190		)	(244,726		)	(111,775		)	—			(356,691		)
	Other (expense) income:
	Other income (expense)	5			2,169			(288		)	—			1,886
	Foreign exchange (loss) gain, net	(9,896		)	11			9,509			—			(376		)
	Interest (expense) income, net of capitalized interest	(64,392		)	3,807			(7,099		)	—			(67,684		)
	Impairment of investment at cost	—			(9,411		)	—			—			(9,411		)
	Interest income (expense) from intercompany notes	36,724			(2,493		)	(34,231		)	—			—
	Equity loss from consolidated subsidiaries	(330,604		)	(7,674		)	—			338,278			—
		(368,163		)	(13,591		)	(32,109		)	338,278			(75,585		)
	Loss from continuing operations before income taxes and equity earnings	(368,353		)	(258,317		)	(143,884		)	338,278			(432,276		)
	Income tax (expense) benefit	(6,030		)	23,130			53,843			—			70,943
Equity in loss of affiliates	—			(6,529		)	(2,640		)	—			(9,169		)
Loss from continuing operations	(374,383		)	(241,716		)	(92,681		)	338,278			(370,502		)
Loss from discontinued operations, net of tax	—			—			(6,427		)	—			(6,427		)
Net loss	(374,383		)	(241,716		)	(99,108		)	338,278			(376,929		)
Net income attributable to noncontrolling interest	—			—			2,546			—			2,546
Net loss attributable to Molycorp stockholders	$	(374,383	)	$	(241,716	)	$	(96,562	)	$	338,278		$	(374,383	)
Net loss	$	(374,383	)	$	(241,716	)	$	(99,108	)	$	338,278		$	(376,929	)
Other comprehensive income:
Foreign currency translation adjustments	$	—		$	—		$	1,623		$	—		$	1,623
Actuarial gain	—			—			1,359			—			1,359
Comprehensive loss	$	(374,383	)	$	(241,716	)	$	(96,126	)	$	338,278		$	(373,947	)
Comprehensive loss attributable to:
Molycorp stockholders	(374,383		)	(241,716		)	(93,580		)	338,278			(371,401		)
Noncontrolling interest	—			—			(2,546		)	—			(2,546		)
	$	(374,383	)	$	(241,716	)	$	(96,126	)	$	338,278		$	(373,947	)
	Year Ended December 31, 2012
	(In thousands)
Condensed Consolidating Statements of Operations and Comprehensive Income	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations			Molycorp, Inc. consolidated
Revenues	$	—		$	139,257		$	413,951		$	(25,512	)	$	527,696
Costs of sales:
Costs excluding depreciation and amortization	—			(153,461		)	(350,304		)	25,512			(478,253		)
Depreciation and amortization	—			(12,094		)	(18,527		)	—			(30,621		)
Gross (loss) profit	—			(26,298		)	45,120			—			18,822
Operating expenses:
Selling, general and administrative	46			(86,493		)	(26,990		)	—			(113,437		)
Corporate development	(46		)	(19,750		)	—			—			(19,796		)
Depreciation, amortization and accretion	—			(2,220		)	(19,967		)	—			(22,187		)
Research and development	—			(12,984		)	(14,812		)	—			(27,796		)
Impairment of goodwill and other long-lived assets	—			(5,747		)	(296,008		)	—			(301,755		)
Operating loss	—			(153,492		)	(312,657		)	—			(466,149		)
Other (expense) income:
Other expense	(37,589		)	(328		)	(881		)	—			(38,798		)
Foreign exchange gain, net	—			—			2,872			—			2,872
Interest expense, net of capitalized interest	(18,118		)	(3,496		)	(502		)	—			(22,116		)
Interest income (expense) from intercompany notes	25,157			3,152			(28,309		)	—			—
Equity loss from consolidated subsidiaries	(456,649		)	(23,205		)	—			479,854			—
	(487,199		)	(23,877		)	(26,820		)	479,854			(58,042		)
Loss from continuing operations before income taxes and equity earnings	(487,199		)	(177,369		)	(339,477		)	479,854			(524,191		)
Income tax benefit (expense)	6,030			53,840			(5,795		)	—			54,075
Equity in loss of affiliates	—			(2,439		)	(1,051		)	—			(3,490		)
Loss from continuing operations	(481,169		)	(125,968		)	(346,323		)	479,854			(473,606		)
Loss from discontinued operations, net of tax	—			—			(1,737		)	—			(1,737		)
Net loss	(481,169		)	(125,968		)	(348,060		)	479,854			(475,343		)
Net income attributable to noncontrolling interest	—			—			(5,826		)	—			(5,826		)
Net loss attributable to Molycorp stockholders	$	(481,169	)	$	(125,968	)	$	(353,886	)	$	479,854		$	(481,169	)
Net loss	$	(481,169	)	$	(125,968	)	$	(348,060	)	$	479,854		$	(475,343	)
Other comprehensive income:
Foreign currency translation adjustments	—			—			248			—			248
Actuarial loss	—			—			(1,200		)	—			(1,200		)
Comprehensive loss	$	(481,169	)	$	(125,968	)	$	(349,012	)	$	479,854		$	(476,295	)
Comprehensive loss attributable to:
Molycorp stockholders	(481,169		)	(125,968		)	(354,838		)	479,854			(482,121		)
Noncontrolling interest	—			—			5,826			—			5,826
	$	(481,169	)	$	(125,968	)	$	(349,012	)	$	479,854		$	(476,295	)
Schedule of Condensed Cash Flow Statement
		Year Ended December 31, 2014
		(In thousands)
	Condensed Consolidating Statements of Cash Flows	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations			Molycorp, Inc. consolidated
	Net cash (used in) provided by operating activities	$	(65,618	)	$	(178,939	)	$	22,353		$	—		$	(222,204	)
	Cash flows from investing activities:
	Intercompany advances made	(111,753		)	(2,123		)	(55,578		)	169,454			—
	Repayments from non-guarantor	39,662			—			—			(39,662		)	—
	Loans to guarantors	—						(6,655		)	6,655			—
	Loans to non-guarantors	(4,000		)	(5,000		)	—			9,000			—
	Investment in joint ventures	—			—			(703		)	—			(703		)
	Dividends received from equity investment	—			—			2,014			—			2,014
	Capital expenditures	—			(78,557		)	(7,601		)	—			(86,158		)
	Recovery from insurance claims	—			12,900			—			—			12,900
	Other investing activities	—			90			894			—			984
	Net cash used in investing activities	(76,091		)	(72,690		)	(67,629		)	145,447			(70,963		)
	Cash flows from financing activities:
	Repayments of debt	—			—			(7,825		)	—			(7,825		)
	Debt issuance costs	(4,190		)	(7,750		)	(3,320		)	—			(15,260		)
	Proceeds from the 2014 Financings	50,167			139,833			60,000			—			250,000
	Partial repayment of convertible notes	(27,495		)	—			—			—			(27,495		)
	Payments of preferred dividends	(2,846		)	—			—			—			(2,846		)
	Dividend paid to noncontrolling interests	—			—			(4,222		)	—			(4,222		)
	Borrowing from non-guarantor	—			6,655			—			(6,655		)	—
	Borrowings from parent	—			—			4,000			(4,000		)	—
	Borrowings from guarantor	—			—			5,000			(5,000		)	—
	Repayments to parent	—			—			(39,662		)	39,662			—
	Intercompany advances owed	55,578			111,753			2,123			(169,454		)	—
	Net cash provided by financing activities	71,214			250,491			16,094			(145,447		)	192,352
	Effect of exchange rate changes on cash	—			—			(1,817		)	—			(1,817		)
	Net change in cash and cash equivalents	(70,495		)	(1,138		)	(30,999		)	—			(102,632		)
	Cash and cash equivalents at beginning of the period	169,145			6,467			138,705			—			314,317
	Cash and cash equivalents at end of period	$	98,650		$	5,329		$	107,706		$	—		$	211,685
		Year Ended December 31, 2013
		(In thousands)
	Condensed Consolidating Statements of Cash Flows	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations			Molycorp, Inc. consolidated
	Net cash (used in) provided by operating activities	$	(39,075	)	$	(133,612	)	$	18,336		$	—		$	(154,351	)
	Cash flows from investing activities:
	Loans to guarantor	—			—			(40,000		)	40,000			—
	Loans to Parent	—			—			(12,800		)	12,800			—
	Intercompany advances made	(391,560		)	—			—			391,560			—
	Loans to non-guarantor	(117,512		)	(1,300		)	—			118,812			—
	Repayments of notes receivable from non-guarantor	38,000			117,776			—			(155,776		)	—
	Investment in joint ventures	—			(3,423		)	—			—			(3,423		)
	Capital expenditures	—			(361,782		)	(17,530		)	—			(379,312		)
	Other investing activities	—			4,902			575			—			5,477
	Net cash used in investing activities	(471,072		)	(243,827		)	(69,755		)	407,396			(377,258		)
	Cash flows from financing activities:
	Repayments of debt	—			—			(26,823		)	—			(26,823		)
	Net proceeds from sale of common stock	495,717			—			—			—			495,717
	Issuance of 5.50% Convertible Notes	165,600			—			—			—			165,600
	Payments of preferred dividends	(11,385		)	—			—			—			(11,385		)
	Dividend paid to noncontrolling interests	—			—			(4,546		)	—			(4,546		)
	Borrowing from non-guarantor	12,800			40,000			—			(52,800		)	—
	Borrowings from parent	—			—			117,512			(117,512		)	—
	Borrowings from guarantor	—			—			1,300			(1,300		)	—
	Repayments to parent	—			—			(38,000		)	38,000			—
	Repayments to guarantor	—			—			(117,776		)	117,776			—
	Intercompany advances owed	—			327,183			64,377			(391,560		)	—
	Other financing activities	—			(1,297		)	—			—			(1,297		)
	Net cash provided by financing activities	662,732			365,886			(3,956		)	(407,396		)	617,266
	Effect of exchange rate changes on cash	—			—			870			—			870
	Net change in cash and cash equivalents	152,585			(11,553		)	(54,505		)	—			86,527
	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	$	169,145		$	6,467		$	138,705		$	—		$	314,317
	Year Ended December 31, 2012
	(In thousands)
Condensed Consolidating Statements of Cash Flows	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations			Molycorp, Inc. consolidated
Net cash (used in) provided by operating activities	$	(13,207	)	$	(112,386	)	$	35,958		$	—		$	(89,635	)
Cash flows from investing activities:
Cash paid in connection with acquisitions, net of cash acquired	—			—			(591,011		)	—			(591,011		)
Loans to subsidiaries	(697,213		)	—			—			697,213			—
Loans to Parent	—			(37,589		)	—			37,589			—
Intercompany advances made	(1,009,014		)	—			—			1,009,014			—
Repayments from subsidiaries	101,974			—			—			(101,974		)	—
Investment in subsidiaries	(350,000		)	—			—			350,000			—
Notes receivable to non-guarantor	—			(227,512		)	—			227,512			—
Repayments of notes receivable from non-guarantor	—			110,000			—			(110,000		)	—
Investment in joint ventures	—			(27,680		)	(5,364		)	—			(33,044		)
Capital expenditures	—			(766,951		)	(24,518		)	—			(791,469		)
Acquisition of exploration rights	—			—			(8,167		)	—			(8,167		)
Other investing activities	—			(3,999		)	4,761			—			762
Net cash used in investing activities	(1,954,253		)	(953,731		)	(624,299		)	2,109,354			(1,422,929		)
Cash flows from financing activities:
Capital contributions from stockholder	390,093			—			—			—			390,093
Capital contributions from Parent	—			—			350,000			(350,000		)	—
Repayments of debt	—			(870		)	(227,838		)	—			(228,708		)
Net proceeds from sale of common stock	132,130			—			—			—			132,130
Issuance of 10% Senior Secured Notes	635,373			—			—			—			635,373
Issuance of 6.00% Convertible Notes	395,712			—			—			—			395,712
Payments of preferred dividends	(11,385		)	—			—			—			(11,385		)
Dividend paid to noncontrolling interests	—			—			(5,977		)	—			(5,977		)
Proceeds from debt	—			—			14,699			—			14,699
Borrowings from parent	—			227,512			469,701			(697,213		)	—
Repayments of borrowings to parent	—			(34,327		)	(67,647		)	101,974			—
Borrowing from guarantor	37,589			—			227,512			(265,101		)	—
Repayments of borrowings to guarantor	—			—			(110,000		)	110,000			—
Intercompany advances owed	—			881,179			127,835			(1,009,014		)	—
Other financing activities	(2,938		)	(115		)	1,499			—			(1,554		)
Net cash provided by financing activities	1,576,574			1,073,379			779,784			(2,109,354		)	1,320,383
Effect of exchange rate changes on cash	—			—			1,116			—			1,116
Net change in cash and cash equivalents	(390,886		)	7,262			192,559			—			(191,065		)
Cash and cash equivalents at beginning of the period	407,446			10,758			651			—			418,855
Cash and cash equivalents at end of period	$	16,560		$	18,020		$	193,210		$	—		$	227,790
Schedule of Out-of-Period Adjustments	The out-of-period adjustment had the following impact on the consolidated balance sheet and the consolidated statement of operations and comprehensive loss in 2014:
	Increase to balance sheet captions:	(In thousands)
	Other current assets	$	91
	Inventory	2,339
	Property, plant and equipment	7,742
	Other non-current assets	275
	Other current liabilities	8
	Accumulated other comprehensive income	14,281
	Increase (decrease) to statements of operations and comprehensive loss captions:
	Revenues	$	270
	Costs of sales	5,745
	Foreign exchange gain	1,633
	Net loss	3,842
	Foreign currency translation adjustments	(14,281		)
	Comprehensive loss	(10,439		)
	The changes in the presentation of the Condensed Consolidating Balance Sheets at December 31, 2013 and the Condensed Consolidating Statements of Cash Flows for the year ended December 31, 2012 are as follows:
	Condensed Consolidating Balance Sheets	At December 31, 2013
		(In thousands)
	Parent	As reported			Adjustment			Revised
	Investments in consolidated subsidiaries	$	532,767		$	(532,767	)	$	—
	Intercompany accounts receivable	2,001,583			532,767			2,534,350
	Guarantor Subsidiaries							—
	Investments in consolidated subsidiaries	$	121,849		$	(17,522	)	$	104,327
	Additional paid-in capital	149,857			(17,522		)	132,335
	Non-Guarantor Subsidiaries							—
	Intercompany accounts payable	$	2,021		$	780,990		$	783,011
	Additional paid-in capital	1,315,426			(780,990		)	534,436
	Condensed Consolidating Statements of Cash Flows	At December 31, 2012
		(In thousands)
	Parent	As reported			Adjustment			Revised
	Loans to subsidiaries	$	(683,063	)	$	(14,150	)	$	(697,213	)
	Repayments from subsidiaries	87,824			14,150			101,974
	Non-Guarantor Subsidiaries							—
	Borrowing from parent	$	455,551		$	14,150		$	469,701
	Repayments of borrowings to parent	(53,497		)	(14,150		)	(67,647		)

Discontinued_Operations_Tables

Discontinued Operations (Tables)	12 Months Ended
	Dec. 31, 2014
Discontinued Operations and Disposal Groups [Abstract]
Schedule of Disposal Groups, Including Discontinued Operations, Income Statement, Balance Sheet and Additional Disclosures	The following table summarizes the operating results of the Napanee facility included in discontinued operations for the years ended December 31, 2013 and 2012:
		December 31,			June 12 -December 31,
		2013			2012
		(In thousands)
	Revenues	$	2,091		$	1,214
	Costs of sales	(3,834		)	(2,691		)
	Selling, general and administrative expenses	(351		)	(232		)
	Depreciation	(28		)	(28		)
	Operating loss	(2,122		)	(1,737		)
	Impairment loss	(4,305		)	—
	Income tax	—			—
	Net loss	$	(6,427	)	$	(1,737	)

Unaudited_Supplementary_Data_T

Unaudited Supplementary Data (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	The following is a summary of the selected quarterly financial information (unaudited):
		2014
		Quarter ended
		31-Mar			30-Jun			30-Sep			31-Dec
		(In thousands, except per share data)
	Revenues	$	118,526		$	116,907		$	123,937		$	116,242
	Gross loss	(23,094		)	(16,571		)	(15,078		)	(44,844		)
	Loss from continuing operations before income taxes and equity earnings (a)	(86,182		)	(89,724		)	(99,484		)	(343,375		)
	Net loss	(85,998		)	(83,850		)	(105,148		)	(347,938		)
	Net loss attributable to Molycorp stockholders (b)	(86,061		)	(83,899		)	(105,179		)	(329,795		)
	Loss per share of common stock from continuing operations: (c)
	Basic	(0.40		)	(0.37		)	(0.47		)	(1.43		)
	Diluted	(0.40		)	(0.37		)	(0.47		)	(1.43		)
		2013
		Quarter ended
		31-Mar			30-Jun			30-Sep			31-Dec
		(In thousands, except per share data)
	Revenues	$	145,398		$	136,112		$	149,066		$	123,814
	Gross loss	(4,305		)	(18,036		)	(17,778		)	(27,049		)
	Loss from continuing operations before income taxes and equity earnings (d)	(57,249		)	(70,254		)	(76,181		)	(228,592		)
	Net loss	(38,153		)	(70,689		)	(69,799		)	(198,288		)
	Net loss attributable to Molycorp stockholders	(38,971		)	(71,175		)	(69,929		)	(194,308		)
	Loss per share of common stock from continuing operations: (c)
	Basic	(0.27		)	(0.44		)	(0.43		)	(0.95		)
	Diluted	(0.27		)	(0.44		)	(0.43		)	(0.95		)
	(a)	Includes the following adjustments:
	i.	Second quarter out-of-period adjustment of $4.9 million (see Note 16);
	ii.	Third quarter impairment charge of $12.0 million (see Note 10);
	iii.	Fourth quarter out-of-period adjustment of $3.8 million (see Note 3);
	iv.	Fourth quarter impairment charges for: goodwill, $125.9 million; customer relationships, $90.9 million; long-lived tangible assets, 14.4 million; net gain on extinguishment of convertible notes, $19.7 million (see Notes 7, 9 and 14, respectively).
	(b)	Includes charges for equity method investments write-off totaling $19.7 million (see Note 10).
	(c)	The sum of the quarterly loss per share may be different than the per share amount for the year as the calculation for each quarter is based on the weighted average shares outstanding for that period.
	(d)	Includes the following impairment charges in the fourth quarter: goodwill, $11.0 million; rare earths quotas, $67.2 million; patents, $10.2 million; exploration rights, $16.2 million; cost method investments, $9.4 million; and long-lived tangible assets, $16.3 million (see Notes 7, 9 and 10).

Going_Concern_Details

Going Concern (Details) (USD $)	1 Months Ended		3 Months Ended	12 Months Ended			0 Months Ended
	Nov. 30, 2014	Aug. 31, 2014	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 11, 2014	Dec. 31, 2011	Dec. 30, 2014	Jun. 15, 2011	Jan. 30, 2013	Aug. 22, 2012
Capital Expenditures [Line Items]
Debt Instrument, Face Amount			$1,700,000,000	$1,700,000,000
Interest Paid				124,000,000
Cash and cash equivalents			211,685,000	211,685,000	314,317,000	227,790,000		418,855,000
Debt and Lease Financing Commitment Capacity		400,000,000
Proceeds from issuance of secured debt				250,000,000	0	0
Debt Conversion, Converted Instrument, Shares Issued	15,100,000		15,056,603
Molycorp Mountain Pass facility
Capital Expenditures [Line Items]
Expected capital expenditures in 2015			45,000,000	45,000,000
Expected capital expenditures in 2016			65,000,000	65,000,000
Expansion Capital Expenditures | Minimum
Capital Expenditures [Line Items]
Expected capital expenditures in 2015			15,000,000	15,000,000
Expansion Capital Expenditures | Maximum
Capital Expenditures [Line Items]
Expected capital expenditures in 2015			20,000,000	20,000,000
Convertible Debt
Capital Expenditures [Line Items]
Debt Instrument, Obligation to Offer to Repurchase If Contingencies Are Not Met, Equal to Percent of Aggregate Principal Plus Accrued and Unpaid Interest									100.00%
Convertible Debt | 3.25% Convertible Notes, net of discount, due June 2016
Capital Expenditures [Line Items]
Debt Instrument, Face Amount										230,000,000
Long-term Debt, Gross			206,505,000	206,505,000	230,000,000
Interest Rate, Stated Percentage			3.25%	3.25%	3.25%					3.25%
Convertible Debt | 5.50% Convertible Notes, net of discount, due February 2018
Capital Expenditures [Line Items]
Debt Instrument, Face Amount			11,000,000	11,000,000							150,000,000
Long-term Debt, Gross			161,500,000	161,500,000	172,500,000
Interest Rate, Stated Percentage			5.50%	5.50%	5.50%						5.50%
Debt Conversion, Converted Instrument, Shares Issued			4,358,490
Convertible Debt | 6.00% Convertible Notes, net of discount, due September 2017
Capital Expenditures [Line Items]
Debt Instrument, Face Amount			27,000,000	27,000,000								360,000,000
Long-term Debt, Gross			383,000,000	383,000,000	414,000,000
Interest Rate, Stated Percentage			6.00%	6.00%	6.00%	6.00%						6.00%
Debt Conversion, Converted Instrument, Shares Issued			10,698,113
Secured Debt | 12% Term Loans and 12% Equipment Financing
Capital Expenditures [Line Items]
Proceeds from issuance of secured debt							250,000,000
Debt and Lease Financing Commitment Capacity, Availability Contingent Upon Achieving Performance Targets							134,800,000
Unused borrowing capacity, amount							149,800,000
Secured Debt | Magnequench Term Loan
Capital Expenditures [Line Items]
Proceeds from issuance of secured debt							60,000,000
Debt and Lease Financing Commitment Capacity, Availability Contingent Upon Achieving Performance Targets							5,000,000
Unused borrowing capacity, amount							$15,000,000

Summary_of_Significant_Account3

Summary of Significant Accounting Policies (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Allowance for doubtful accounts	$2,600,000	$2,600,000
Revenues
Property, Plant and Equipment [Line Items]
Out-of-Period Adjustments, Interim Periods of Fiscal Year	270,000
Costs of sales
Property, Plant and Equipment [Line Items]
Out-of-Period Adjustments, Interim Periods of Fiscal Year	5,745,000
Foreign exchange gain
Property, Plant and Equipment [Line Items]
Out-of-Period Adjustments, Interim Periods of Fiscal Year	1,633,000
Net loss
Property, Plant and Equipment [Line Items]
Out-of-Period Adjustments, Interim Periods of Fiscal Year	3,842,000
Foreign currency translation adjustments
Property, Plant and Equipment [Line Items]
Out-of-Period Adjustments, Interim Periods of Fiscal Year	-14,281,000
Comprehensive loss
Property, Plant and Equipment [Line Items]
Out-of-Period Adjustments, Interim Periods of Fiscal Year	-10,439,000
Other current assets
Property, Plant and Equipment [Line Items]
Out-of-Period Adjustments, Interim Periods of Fiscal Year	91,000
Inventory
Property, Plant and Equipment [Line Items]
Out-of-Period Adjustments, Interim Periods of Fiscal Year	2,339,000
Property, plant and equipment
Property, Plant and Equipment [Line Items]
Out-of-Period Adjustments, Interim Periods of Fiscal Year	7,742,000
Other non-current assets
Property, Plant and Equipment [Line Items]
Out-of-Period Adjustments, Interim Periods of Fiscal Year	275,000
Other current liabilities
Property, Plant and Equipment [Line Items]
Out-of-Period Adjustments, Interim Periods of Fiscal Year	8,000
Accumulated other comprehensive income
Property, Plant and Equipment [Line Items]
Out-of-Period Adjustments, Interim Periods of Fiscal Year	$14,281,000
Chinese Land Use Rights
Property, Plant and Equipment [Line Items]
Finite-lived intangible asset useful life	50 years
Minimum | Customer relationships
Property, Plant and Equipment [Line Items]
Finite-lived intangible asset useful life	2 years
Minimum | Patents
Property, Plant and Equipment [Line Items]
Finite-lived intangible asset useful life	2 years
Minimum | Trade names
Property, Plant and Equipment [Line Items]
Finite-lived intangible asset useful life	2 years
Maximum | Customer relationships
Property, Plant and Equipment [Line Items]
Finite-lived intangible asset useful life	16 years
Maximum | Patents
Property, Plant and Equipment [Line Items]
Finite-lived intangible asset useful life	16 years
Maximum | Trade names
Property, Plant and Equipment [Line Items]
Finite-lived intangible asset useful life	16 years

Segment_Information_Revenues_E

Segment Information - Revenues, Expenses and Assets (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
									segment
Segment Information
Number of segments									4
Revenues:
Revenues									$475,612	$554,390	$527,696
Total revenues	116,242	123,937	116,907	118,526	123,814	149,066	136,112	145,398	475,612	554,390	527,696
Operating loss									-450,871	-356,691	-466,149
Other expense									-5,092	1,886	-38,798
Foreign exchange (loss) gain, net									-3,146	-376	2,872
Interest expense, net of capitalized interest									-167,375	-67,684	-22,116
Gain on extinguishment of convertible notes, net	19,719								19,719	0	0
Impairment of investment at cost					-9,400				-12,000	-9,411	0
Loss from continuing operations before income taxes and equity earnings	-343,375	-99,484	-89,724	-86,182	-228,592	-76,181	-70,254	-57,249	-618,765	-432,276	-524,191
Total assets	2,575,986				3,006,802				2,575,986	3,006,802
Capital expenditures									57,454	249,487	843,061
Resources
Revenues:
Revenues									14,097	33,621	88,870
Total revenues									48,190	59,661	96,126
Depreciation, amortization and accretion									-78,739	-46,318	-13,991
Operating loss									-224,896	-223,702	-70,220
Total assets	1,593,105				1,791,421				1,593,105	1,791,421
Capital expenditures									49,364	231,027	814,054
Chemicals and Oxides
Revenues:
Revenues									159,365	181,815	181,849
Total revenues									181,421	219,071	207,566
Depreciation, amortization and accretion									-17,401	-22,754	-13,110
Operating loss									-219,989	-87,889	-191,059
Total assets	248,040				485,642				248,040	485,642
Capital expenditures									3,907	6,961	10,910
Magnetic Materials and Alloys
Revenues:
Revenues									222,795	252,713	179,335
Total revenues									230,386	252,713	179,335
Depreciation, amortization and accretion									-16,956	-27,812	-19,737
Operating loss									36,010	23,087	-125,543
Total assets	618,314				590,516				618,314	590,516
Capital expenditures									2,120	3,700	5,614
Rare Metals
Revenues:
Revenues									79,355	86,241	77,642
Total revenues									79,355	86,241	77,642
Depreciation, amortization and accretion									-10,343	-8,652	-5,837
Operating loss									-10,785	-21,108	-18,671
Total assets	105,826				82,538				105,826	82,538
Capital expenditures									2,063	7,549	10,750
Corporate and other
Revenues:
Operating loss									-33,195	-46,126	-85,459
Total assets	1,385,265				1,547,267				1,385,265	1,547,267
Capital expenditures									0	250	1,733
Intersegment Eliminations
Revenues:
Revenues									0	0	0
Total revenues									-63,740	-63,296	-32,973
Operating loss									1,984	-953	24,803
Total assets	-1,374,564				-1,490,582				-1,374,564	-1,490,582
Capital expenditures									0	0	0
Intersegment Eliminations
Revenues:
Revenues									0	0	0
Intersegment Eliminations | Resources
Revenues:
Revenues									34,093	26,040	7,256
Intersegment Eliminations | Chemicals and Oxides
Revenues:
Revenues									22,056	37,256	25,717
Intersegment Eliminations | Magnetic Materials and Alloys
Revenues:
Revenues									7,591	0	0
Intersegment Eliminations | Rare Metals
Revenues:
Revenues									0	0	0
Intersegment Eliminations | Intersegment Eliminations
Revenues:
Revenues									-63,740	-63,296	-32,973
Operating Segments | Resources
Revenues:
OIBDA									-146,157	-177,384	-56,229
Operating Segments | Chemicals and Oxides
Revenues:
OIBDA									-202,588	-65,135	-177,949
Operating Segments | Magnetic Materials and Alloys
Revenues:
OIBDA									52,966	50,899	-105,806
Operating Segments | Rare Metals
Revenues:
OIBDA									($442)	($12,456)	($12,834)

Segment_Information_Geography_

Segment Information - Geography (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$475,612	$554,390	$527,696
Long-lived assets	1,707,970	1,762,874
China
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	162,980	199,021	118,086
Long-lived assets	49,930	53,131
Japan
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	100,468	99,952	160,942
Thailand
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	19,585	17,129	7,674
Long-lived assets	5,457	6,213
Hong Kong
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	0	8,815	4,793
South Korea
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	14,451	12,418	3,828
Singapore
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	150	54	212
North America
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	89,769	92,066	103,555
Long-lived assets	1,582,291	1,627,892
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	86,285	113,549	117,907
Long-lived assets	68,212	73,674
Other Asia
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	2,080	1,913
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	1,924	11,386	10,699
Long-lived assets	$0	$51

Inventory_Current_and_LongTerm

Inventory - Current and Long-Term (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current:
Concentrate stockpiles	$0	$24
Raw materials	47,796	42,627
Work in process	24,901	41,962
Finished goods	67,795	65,662
Materials and supplies	28,831	21,508
Total current	169,323	171,783
Long-term:
Concentrate stockpiles	0	4
Raw materials	25,127	25,325
Total long-term	$25,127	$25,329

Inventory_Schedule_of_Charges_

Inventory - Schedule of Charges to Cost of Sales (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Inventory [Line Items]
Abnormal production costs expensed in the period	$93,917	$88,070	$11,982
Write-downs of stockpile inventory	178,331	188,416	95,021
Rare earth metals
Inventory [Line Items]
Write-down to the lower of cost or market	84,414	100,346	80,939
Stockpile
Inventory [Line Items]
Write-down to the lower of cost or market	$0	$0	$2,100

Deposits_Details

Deposits (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Deposits [Line Items]
Deposits	$31,078	$25,997
Construction insurance program	2,710	1,504
Collateral placed against the surety bonds issued to California state and regional agencies for the closure and reclamation obligations at the Mountain Pass facility, and other deposits	7,756	3,881
Kern River Gas Transmission Company
Deposits [Line Items]
Escrow arrangement with Kern River Gas Transmission Company (Kern River)	$20,612	$20,612

Property_Plant_and_Equipment_n2

Property, Plant and Equipment, net - Schedule of Depreciation and Totals (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property, plant and equipment at cost	$1,900,310	$1,865,552
Less accumulated depreciation	-192,340	-102,678
Property, plant and equipment, net	1,707,970	1,762,874
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment at cost	13,121	12,822
Land improvements (15 to 30 years)
Property, Plant and Equipment [Line Items]
Property, plant and equipment at cost	305,119	327,029
Land improvements (15 to 30 years) | Minimum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	15 years
Land improvements (15 to 30 years) | Maximum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	30 years
Buildings and improvements (4 to 40 years)
Property, Plant and Equipment [Line Items]
Property, plant and equipment at cost	811,418	418,510
Buildings and improvements (4 to 40 years) | Minimum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	4 years
Buildings and improvements (4 to 40 years) | Maximum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	40 years
Plant and equipment (2 to 15 years)
Property, Plant and Equipment [Line Items]
Property, plant and equipment at cost	623,453	288,603
Plant and equipment (2 to 15 years) | Minimum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	2 years
Plant and equipment (2 to 15 years) | Maximum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	15 years
Vehicles (7 years)
Property, Plant and Equipment [Line Items]
Property, plant and equipment at cost	2,884	2,986
Property, Plant and Equipment, Useful Life	7 years
Computer software (5 years)
Property, Plant and Equipment [Line Items]
Property, plant and equipment at cost	12,268	12,424
Property, Plant and Equipment, Useful Life	5 years
Furniture and fixtures (5 years)
Property, Plant and Equipment [Line Items]
Property, plant and equipment at cost	1,039	1,044
Property, Plant and Equipment, Useful Life	5 years
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment at cost	80,699	755,107
Natural gas delivery facility under capital lease (10 years)
Property, Plant and Equipment [Line Items]
Capital Leased Assets, Gross	15,658	15,658
Property, Plant and Equipment, Useful Life	10 years
Mining equipment under capital lease (7 years)
Property, Plant and Equipment [Line Items]
Capital Leased Assets, Gross	10,982	7,370
Property, Plant and Equipment, Useful Life	7 years
Mineral properties (Note 8)
Property, Plant and Equipment [Line Items]
Property, plant and equipment at cost	$23,669	$23,999

Property_Plant_and_Equipment_n3

Property, Plant and Equipment, net - Narrative (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Additions	$57,454,000	$249,487,000	$843,061,000
Property, Plant and Equipment, Additions, Gross of Capitalized Interest		320,700,000	902,300,000
Interest Costs Capitalized		71,200,000	59,300,000
Depreciation	97,800,000	60,300,000	20,900,000
Tangible Asset Impairment Charges	14,400,000	16,300,000	5,900,000
Recovery from insurance claims	12,900,000	0	0
Molycorp Mountain Pass facility
Property, Plant and Equipment [Line Items]
Tangible Asset Impairment Charges	13,600,000	14,200,000	3,800,000
Assets Held under Capital Leases
Property, Plant and Equipment [Line Items]
Depreciation	$2,800,000	$2,300,000	$900,000

Mineral_Properties_Narrative_D

Mineral Properties - Narrative (Details) (USD $)	12 Months Ended			0 Months Ended	3 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Property, plant and equipment at cost	$1,900,310,000	$1,865,552,000		$1,865,552,000
Payments to acquire exploration rights	0	0	8,167,000
Tangible Asset Impairment Charges	14,400,000	16,300,000	5,900,000
Exploration rights
Property, Plant and Equipment [Line Items]
Property, plant and equipment at cost			16,200,000		16,200,000
Issuance of shares for investment in mining property					788,410
Sale of stock, price per share			$10.15		$10.15
Payments to acquire exploration rights					8,200,000
Tangible Asset Impairment Charges				$16,200,000

Goodwill_and_Other_Intangible_2

Goodwill and Other Intangible Assets - Narrative (Details) (USD $)	3 Months Ended	12 Months Ended			3 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Goodwill [Line Items]
Impairment	($125,900,000)	($125,942,000)	($10,992,000)	($289,894,000)
Goodwill, impairment loss from initial purchase price allocation			258,300,000
Amortization expense		23,904,000	43,556,000	28,600,000
Customer relationships
Goodwill [Line Items]
Amortization expense		23,019,000	22,145,000
Rare earths quotas
Goodwill [Line Items]
Amortization expense		0	7,018,000
Patents
Goodwill [Line Items]
Amortization expense		125,000	13,554,000
Trade names
Goodwill [Line Items]
Intangible assets not subject to amortization	14,800,000	14,800,000
Molycorp Canada
Goodwill [Line Items]
Impairment				-287,900,000
Goodwill, additional impairment loss from final purchase price allocation					31,600,000	31,600,000
Chemicals and Oxides
Goodwill [Line Items]
Impairment		-125,229,000	0	-161,132,000
Chemicals and Oxides | Rare earths quotas
Goodwill [Line Items]
Impairment of Intangible Assets (Excluding Goodwill)					67,200,000
Rare Metals
Goodwill [Line Items]
Impairment		-700,000	-10,992,000	-16,068,000	-11,000,000
Chemicals and Oxides and Rare Metals | Customer relationships
Goodwill [Line Items]
Impairment of Intangible Assets (Excluding Goodwill)	90,900,000
Magnetic Materials and Alloys
Goodwill [Line Items]
Impairment		0	0	-112,694,000
Goodwill, Fair Value excess over Carrying Value, Percent	10.00%	10.00%
Magnetic Materials and Alloys | Patents
Goodwill [Line Items]
Impairment of Intangible Assets (Excluding Goodwill)					10,200,000	6,000,000
Fair Value, Inputs, Level 3 | Income Approach Valuation Technique
Goodwill [Line Items]
fair value input, customer attrition	13.00%
Noncontrolling interests
Goodwill [Line Items]
Out-of-Period Adjustments, Interim Periods of Fiscal Year		$10,300,000

Goodwill_and_Other_Intangible_3

Goodwill and Other Intangible Assets - Goodwill Roll Forward (Details) (USD $)	3 Months Ended	12 Months Ended			3 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013
Goodwill [Roll Forward]
Beginning of period		$228,750	$239,742	$3,432
Goodwill acquired				526,204
Impairment	-125,900	-125,942	-10,992	-289,894
End of period	102,808	102,808	228,750	239,742	228,750
Chemicals and Oxides
Goodwill [Roll Forward]
Beginning of period		125,229	125,229	728
Goodwill acquired				285,633
Impairment		-125,229	0	-161,132
End of period	0	0	125,229	125,229	125,229
Magnetic Materials and Alloys
Goodwill [Roll Forward]
Beginning of period		102,808	102,808	1,977
Goodwill acquired				213,525
Impairment		0	0	-112,694
End of period	102,808	102,808	102,808	102,808	102,808
Rare Metals
Goodwill [Roll Forward]
Beginning of period		713	11,705	727
Goodwill acquired				27,046
Impairment		-700	-10,992	-16,068	-11,000
End of period	$0	$0	$713	$11,705	$713

Goodwill_and_Other_Intangible_4

Goodwill and Other Intangible Assets - Intangible Assets Roll Forward (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Gross carrying amount
At period start	$368,306	$479,900
Additions	37	48
Foreign currency translation adjustment	177	-242
Impairment	-121,425	-111,400
At period end	247,095	368,306	479,900
Accumulated Amortization
At period start	37,439	28,962
Amortization	23,904	43,556	28,600
Adjustments		-1,134
Impairment	-30,119	-33,945
At period end	31,224	37,439	28,962
Net book value	215,871	330,867
Customer relationships
Gross carrying amount
At period start	344,580	344,774
Additions	0	48
Foreign currency translation adjustment	177	-242
Impairment	-121,057	0
At period end	223,700	344,580
Accumulated Amortization
At period start	35,980	14,095
Amortization	23,019	22,145
Adjustments		-260
Impairment	-30,119	0
At period end	28,880	35,980
Net book value	194,820	308,600
Rare earths quotas
Gross carrying amount
At period start	0	78,300
Additions	0	0
Foreign currency translation adjustment	0	0
Impairment	0	-78,300
At period end	0	0
Accumulated Amortization
At period start	0	4,035
Amortization	0	7,018
Adjustments		0
Impairment	0	-11,053
At period end	0	0
Net book value	0	0
Patents
Gross carrying amount
At period start	152	33,252
Additions	0	0
Foreign currency translation adjustment	0	0
Impairment	0	-33,100
At period end	152	152
Accumulated Amortization
At period start	27	9,365
Amortization	125	13,554
Adjustments		0
Impairment	0	-22,892
At period end	152	27
Net book value	0	125
Trade names
Gross carrying amount
At period start	15,586	15,586
Additions	0	0
Foreign currency translation adjustment	0	0
Impairment	0	0
At period end	15,586	15,586
Accumulated Amortization
At period start	343	1,152
Amortization	66	65
Adjustments		-874
Impairment	0	0
At period end	409	343
Net book value	15,177	15,243
Land use rights
Gross carrying amount
At period start	3,568	3,568
Additions	0	0
Foreign currency translation adjustment	0	0
Impairment	-368	0
At period end	3,200	3,568
Accumulated Amortization
At period start	227	66
Amortization	77	161
Adjustments		0
Impairment	0	0
At period end	304	227
Net book value	2,896	3,341
Other
Gross carrying amount
At period start	4,420	4,420
Additions	37	0
Foreign currency translation adjustment	0	0
Impairment	0	0
At period end	4,457	4,420
Accumulated Amortization
At period start	862	249
Amortization	617	613
Adjustments		0
Impairment	0	0
At period end	1,479	862
Net book value	$2,978	$3,558

Goodwill_and_Other_Intangible_5

Goodwill and Other Intangible Assets - Future Amortization Schedule (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Goodwill and Intangible Assets Disclosure [Abstract]
2015	$16,441
2016	16,441
2017	16,441
2018	16,277
2019	16,277
Thereafter	$119,194

Investments_Reconciliation_of_

Investments - Reconciliation of Carrying Value of Investments (Details) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Equity and Cost Method Investment [Roll Forward]
Impairment	($9,400)	($12,000)	($9,411)		$0
Beginning of period		0
Additions		703	3,419
Equity (loss) income		-26,763	-9,169		-3,490
Dividends		-2,014	0		0
Impairment		-19,700
Income (Loss) from Equity Method Investments, excluding other-than-temporary impairment		-7,069
End of period	0	0	0
Beginning of period		48,875	64,036
Impairment		-31,694	-9,411
End of period	48,875	8,801	48,875		64,036
Boulder Wind Power, Inc.
Equity and Cost Method Investment [Roll Forward]
Beginning of period		12,000	20,000
Additions						20,000
Impairment		-12,000	-8,000
End of period	12,000	0	12,000
Intermetallics Japan Joint Venture (IMJ)
Equity and Cost Method Investment [Roll Forward]
Beginning of period		22,083	25,193
Additions			3,419
Equity (loss) income		-6,541	-6,529
Adjustment to investments classification		51
Impairment		-14,808
End of period	22,083	785	22,083
Keli
Equity and Cost Method Investment [Roll Forward]
Beginning of period		8,400	11,000
Equity (loss) income		-635	-2,600
Dividends		-2,014
Adjustment to investments classification		-1,240
End of period	8,400	4,511	8,400
Ingal Stade
Equity and Cost Method Investment [Roll Forward]
Beginning of period		4,975	5,015
Equity (loss) income		-51	-40
Adjustment to investments classification		-38
Impairment		-4,886
End of period	4,975	0	4,975
Other investments
Equity and Cost Method Investment [Roll Forward]
Beginning of period		1,417	2,828
Additions		703
Impairment			-1,411	[1]
End of period	1,417	3,505	1,417
Adjustment to investments classification		1,227
Equity (loss) income		$158
[1]	The impairment charge in 2013 relates to the disposal of the equity interest in Atlantic Metals & Alloys, LLC.

Investments_Narrative_Details

Investments - Narrative (Details) (USD $)	3 Months Ended	12 Months Ended				3 Months Ended	1 Months Ended		0 Months Ended
	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Sep. 30, 2014	Nov. 30, 2011	Dec. 31, 2014	Dec. 31, 2014	Nov. 28, 2011	Jun. 12, 2012
Schedule of Equity Method Investments [Line Items]
Impairment of investments	$9,400,000	$12,000,000	$9,411,000	$0
Contributions to complete acquisition		703,000	3,419,000
Boulder Wind Power, Inc.
Schedule of Equity Method Investments [Line Items]
Investment in Boulder Wind Power's Series B convertible preferred stock					20,000,000
Impairment of investments		12,000,000	8,000,000
Boulder Wind Power, Inc. | Other Nonoperating Income (Expense)
Schedule of Equity Method Investments [Line Items]
Impairment of investments			8,000,000			12,000,000
Intermetallics Japan
Schedule of Equity Method Investments [Line Items]
Contributions to complete acquisition							31,000,000
Intermetallics Japan | Daido
Schedule of Equity Method Investments [Line Items]
Capital contribution ratio (as a percent)										35.50%
Intermetallics Japan | Mitsubishi
Schedule of Equity Method Investments [Line Items]
Capital contribution ratio (as a percent)										34.50%
Intermetallics Japan | Molycorp
Schedule of Equity Method Investments [Line Items]
Capital contribution ratio (as a percent)										30.00%
Intermetallics Japan Joint Venture (IMJ)
Schedule of Equity Method Investments [Line Items]
Contributions to complete acquisition			3,419,000
Proceeds from Sale of Equity Method Investments								1,000,000
Intermetallics Japan Joint Venture (IMJ) | Other Nonoperating Income (Expense)
Schedule of Equity Method Investments [Line Items]
Gain (Loss) on Sale of Equity Investments									-14,800,000
Keli
Schedule of Equity Method Investments [Line Items]
Capital contribution ratio (as a percent)											25.00%
Fair Value of the Equity Investment of a Business Acquisition											12,200,000
Ingal Stade
Schedule of Equity Method Investments [Line Items]
Capital contribution ratio (as a percent)											50.00%
Fair Value of the Equity Investment of a Business Acquisition											4,900,000
Ingal Stade | Other Nonoperating Income (Expense)
Schedule of Equity Method Investments [Line Items]
Gain (Loss) on Sale of Equity Investments									-4,900,000
Gains (Losses) on Extinguishment of Debt, before Write off of Deferred Debt Issuance Cost									($3,300,000)

Acquisitions_Narrative_Details

Acquisitions - Narrative (Details)

1 Months Ended

3 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

0 Months Ended

1 Months Ended

3 Months Ended

12 Months Ended

0 Months Ended

0 Months Ended

0 Months Ended

Jun. 30, 2012

Dec. 31, 2014

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Mar. 28, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Jun. 11, 2012

Jun. 30, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Jun. 11, 2012

Jun. 11, 2012

Jun. 11, 2012

Jun. 11, 2012

Jun. 11, 2012

Dec. 31, 2012

Jun. 11, 2012

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

CAD

JAMR

JAMR

JAMR

Molycorp

MCP Exchangeco Inc.

Molycorp Canada

Molycorp Canada

Molycorp Canada

Molycorp Canada

Molycorp Canada

Molycorp Canada

Molycorp Canada

Molycorp Canada

Scenario, Previously Reported

Scenario, Previously Reported

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

CAD

Molycorp

Molycorp

MCP Exchangeco Inc.

MCP Exchangeco Inc.

Molycorp Canada

Molycorp Canada

USD ($)

USD ($)

Business Acquisition [Line Items]

Total purchase consideration

$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

Notional amount of derivatives

870,000,000

Common stock issued to acquire the entity (in shares)

13,545,426

507,203

13,545,426

507,203

Fair value of Molycorp common stock issued

284,100,000

284,144,000

Goodwill, additional impairment loss from final purchase price allocation

31,600,000

31,600,000

Impairment of goodwill and other intangible assets

125,900,000

125,942,000

10,992,000

289,894,000

287,900,000

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

Additional equity acquired

5.00%

Equity interest, total

95.00%

Additional equity interest, purchase price

15,000,000

Purchase of equity interest, cash portion

5,400,000

9,600,000

Purchase of equity interest, cash portion of accrued interest

$200,000

Acquisitions_Schedule_Details

Acquisitions - Schedule (Details) (USD $)	1 Months Ended	0 Months Ended	12 Months Ended	0 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2012	Jun. 11, 2012
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest [Abstract]
Fair value of Molycorp common stock and Exchangeable Shares issued	$284,100
Molycorp Canada
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest [Abstract]
Cash and cash equivalents		0
Restricted cash		0
Accounts receivable		0
Inventory		0
Prepaid expenses and other current assets		0
Property, plant and equipment		0
Investments		-1,091
Intangible assets		0
Deferred tax charges		0
Deferred tax assets		-1,423
Goodwill		31,616
Other non-current assets		0
Accounts payable and accrued expenses		0
Debt		0
Other current liabilities		0
Deferred tax liabilities		5,880
Other non-current liabilities		0
Non-controlling interests		-34,982
Total purchase consideration		0
Unaudited proforma
Revenues			863,728
Net income (loss)			-463,716
Net income (loss) attributable to Molycorp			-473,249
EPS Basic (in dollars per share)			($4.53)
Molycorp Canada | Preliminary Allocation of Consideration Transferred as of December 31, 2012
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest [Abstract]
Cash consideration					908,181
Fair value of Molycorp common stock and Exchangeable Shares issued					284,144
Total purchase consideration				1,192,325	1,192,325
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	21,019
Intangible assets			482,234	482,234
Deferred tax charges			13,435	13,435
Deferred tax assets			11,473	11,473
Goodwill			494,809	494,809
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	-154,309
Other non-current liabilities			-14,255	-14,255
Non-controlling interests			-15,761	-15,761
Molycorp Canada | Final Allocation of Consideration Transferred
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest [Abstract]
Cash consideration		908,181
Fair value of Molycorp common stock and Exchangeable Shares issued		284,144
Total purchase consideration		1,192,325
Cash and cash equivalents		317,169
Restricted cash		4,951
Accounts receivable		101,470
Inventory		250,989
Prepaid expenses and other current assets		26,893
Property, plant and equipment		75,745
Investments		19,928
Intangible assets		482,234
Deferred tax charges		13,435
Deferred tax assets		10,050
Goodwill		526,425
Other non-current assets		4,367
Accounts payable and accrued expenses		-138,576
Debt		-255,338
Other current liabilities		-33,990
Deferred tax liabilities		-148,429
Other non-current liabilities		-14,255
Non-controlling interests		($50,743)

Acquisitions_Transaction_Costs

Acquisitions - Transaction Costs by Type (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Business Acquisition [Line Items]
Recognized Transaction Costs			$62,000,000
Corporate development:
Legal, accounting and advisory fees	0	247,000	19,796,000
Molycorp Canada
Corporate development:
Legal, accounting and advisory fees			16,498,000
Other expenses:
Contingent forward contract loss			37,589,000
Interest expense:
Bridge loan fee			$7,937,000

Accrued_Expenses_Details

Accrued Expenses (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Accrued Expenses
Defined contribution plan	$613	$1,921
Professional fees	1,955	135
Accrued payroll and related benefits	7,010	5,739
Sales and use tax	2,339	3,354
Bonus accrual	5,109	4,449
Interest payable	18,300	18,158
Advance from customer	130	600
Withholding taxes	376	2,563
Amount payable to noncontrolling interest	2,929	0
Other accrued expenses	13,205	11,582
Total accrued expenses	$51,966	$48,501

Asset_Retirement_Obligation_De

Asset Retirement Obligation (Details) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Asset retirement obligation activity
Balance at beginning of period		$17,583,000	$22,125,000
Obligations settled		-1,549,000	-3,849,000
Accretion expense		1,153,000	1,328,000
Revisions in estimated cash flows	-3,793,000	0	-3,793,000
Loss on settlement		932,000	1,772,000
Balance at end of period	17,583,000	18,119,000	17,583,000	22,125,000
Asset Retirement Obligation [Abstract]
Asset retirement obligation, current	600,000	300,000	600,000
Depreciation expense		600,000	2,500,000	2,000,000
Asset Retirement Obligation, Estimated Future Undiscounted Cash Flows		33,100,000
Revisions in estimated cash flows	-3,793,000	0	-3,793,000
Loss on settlement		932,000	1,772,000
Financial assurance requirement satisfied with surety bonds		$28,800,000
Minimum
Asset Retirement Obligation [Abstract]
Recorded Third-Party Environmental Recoveries, Discount Rate		5.00%
Maximum
Asset Retirement Obligation [Abstract]
Recorded Third-Party Environmental Recoveries, Discount Rate		10.00%

Debt_and_Capital_Lease_Obligat2

Debt and Capital Lease Obligations - Summary of Current and Non-Current Portions (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Debt Instrument [Line Items]
Total debt, Current	$9,326	$14,128
Capital lease obligations, Current	3,234	2,234
Total debt and capital lease obligations, Current	12,560	16,362
Total debt, Non-Current	1,540,570	1,344,561
Capital lease obligations, Non-Current	19,211	19,355
Total debt and capital lease obligations, Non-Current	1,559,781	1,363,916
Notes Payable to Banks | Bank loans due February 2015 - June 2017 | Molycorp Canada and Molycorp Silmet
Debt Instrument [Line Items]
Total debt, Current	9,326	14,128
Total debt, Non-Current	91	2,699
Convertible Debt | 3.25% Convertible Notes, net of discount, due June 2016
Debt Instrument [Line Items]
Total debt, Current	0	0
Total debt, Non-Current	193,549	207,028
Convertible Debt | 6.00% Convertible Notes, net of discount, due September 2017
Debt Instrument [Line Items]
Total debt, Current	0	0
Total debt, Non-Current	335,969	346,708
Convertible Debt | 5.50% Convertible Notes, net of discount, due February 2018
Debt Instrument [Line Items]
Total debt, Current	0	0
Total debt, Non-Current	143,581	148,198
Secured Debt | 12.00% Term Loans, due September 2019
Debt Instrument [Line Items]
Total debt, Current	0	0
Total debt, Non-Current	98,812	0
Secured Debt | 12.00% Equipment Financing, due September 2019
Debt Instrument [Line Items]
Total debt, Current	0	0
Total debt, Non-Current	127,594	0
Convertible Subordinated Debt | 5.00% Debentures, net of discount, due December 2017
Debt Instrument [Line Items]
Total debt, Current	0	0
Total debt, Non-Current	2,075	2,493
Senior Notes | 10% Senior Secured Notes, net of discount, due June 2020
Debt Instrument [Line Items]
Total debt, Current	0	0
Total debt, Non-Current	$638,899	$637,435

Debt_and_Capital_Lease_Obligat3

Debt and Capital Lease Obligations - Reconciliation of the Principal to the Net Carrying Value (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Debt Instrument [Line Items]
Net carrying amount	$1,540,570	$1,344,561
Convertible Debt | 3.25% Convertible Notes, net of discount, due June 2016
Debt Instrument [Line Items]
Long-term Debt, Gross	206,505	230,000
Unamortized debt discount	-12,956	-22,972
Net carrying amount	193,549	207,028
Convertible Debt | 6.00% Convertible Notes, net of discount, due September 2017
Debt Instrument [Line Items]
Long-term Debt, Gross	383,000	414,000
Unamortized debt discount	-47,031	-67,292
Net carrying amount	335,969	346,708
Convertible Debt | 5.50% Convertible Notes, net of discount, due February 2018
Debt Instrument [Line Items]
Long-term Debt, Gross	161,500	172,500
Unamortized debt discount	-17,919	-24,302
Net carrying amount	143,581	148,198
Senior Notes | 10% Senior Secured Notes due June 2020
Debt Instrument [Line Items]
Long-term Debt, Gross	650,000	650,000
Unamortized debt discount	-11,101	-12,565
Net carrying amount	$638,899	$637,435

Debt_and_Capital_Lease_Obligat4

Debt and Capital Lease Obligations - Interest Costs Incurred (Details) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 15, 2011	Jan. 30, 2013	Aug. 22, 2012	25-May-12
Convertible Debt | 3.25% Convertible Notes, net of discount, due June 2016
Debt Instrument [Line Items]
Interest cost	$15,553,000	$15,839,000	$15,312,000
Interest Rate, Stated Percentage	3.25%	3.25%		3.25%
Convertible Debt | 3.25% Convertible Notes, net of discount, due June 2016 | Additional Paid-In Capital
Debt Instrument [Line Items]
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt	36,227			36,200,000
Convertible Debt | 6.00% Convertible Notes, net of discount, due September 2017
Debt Instrument [Line Items]
Interest cost	41,070,000	39,779,000	17,457,000
Interest Rate, Stated Percentage	6.00%	6.00%	6.00%			6.00%
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt			68,695,000
Convertible Debt | 6.00% Convertible Notes, net of discount, due September 2017 | Additional Paid-In Capital
Debt Instrument [Line Items]
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt	68,695		68,695,000
Convertible Debt | 5.50% Convertible Notes, net of discount, due February 2018
Debt Instrument [Line Items]
Interest cost	14,578,000	13,107,000
Interest Rate, Stated Percentage	5.50%	5.50%			5.50%
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt		21,815,000
Convertible Debt | 5.50% Convertible Notes, net of discount, due February 2018 | Additional Paid-In Capital
Debt Instrument [Line Items]
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt	21,815	21,815,000			21,800,000
Senior Notes | 10% Senior Secured Notes due June 2020
Debt Instrument [Line Items]
Interest cost	$66,606,000	$66,323,000	$40,070,000
Interest Rate, Stated Percentage	10.00%	10.00%					10.00%

Debt_and_Capital_Lease_Obligat5

Debt and Capital Lease Obligations - Scheduled Minimum Debt Repayments (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity	20,300,000
Debt maturities, excluding capital leases
2015	9,326,000
2016	206,565,000
2017	385,106,000
2018	161,500,000
2019	321,154,000
Thereafter	650,000,000
Total	1,733,651,000
Notes Payable to Banks | Bank loans due February 2015 - June 2017
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate	4.10%	3.59%

Debt_and_Capital_Lease_Obligat6

Debt and Capital Lease Obligations - 2014 Debt Issuance (Details) (USD $)	3 Months Ended	12 Months Ended			0 Months Ended	4 Months Ended	1 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 11, 2014	Dec. 31, 2014	Sep. 30, 2014	Jun. 15, 2011	Aug. 22, 2012	Jan. 30, 2013
Debt Instrument [Line Items]
Proceeds from issuance of secured debt		$250,000,000	$0	$0
Repayments of convertible debt		27,495,000	0	0
Gain (loss) on extinguishment of debt	19,719,000	19,719,000	0	0
Number of securities called by warrants					24,477,359
Net carrying amount	1,540,570,000	1,540,570,000	1,344,561,000			1,540,570,000
PIK interest		3,851,000	0	0
Secured Debt | 12% Term Loans and 12% Equipment Financing
Debt Instrument [Line Items]
Proceeds from issuance of secured debt					250,000,000
Unused borrowing capacity, amount					149,800,000
Unused borrowing, availability contingent upon achieving performance targets					134,800,000
Proceeds from debt, net of issuance costs					207,100,000
Payment to reduce interest rate					8,000,000
Payments of financing costs					7,300,000
Unamortized debt discount					-28,200,000
Early Payment Premium Percentage
Maximum Principal Amount of Debt Secured by the Pari Passu Collateral					300,000,000
Secured Debt | 12.00% Term Loans, due September 2019
Debt Instrument [Line Items]
Interest Rate, Stated Percentage					12.00%
Interest rate, stated percentage, payment in cash					7.00%
Interest rate, stated percentage, (PIK) interest					5.00%
Unused borrowing capacity, fee					1.00%
Principal amount	111,858,000	111,858,000				111,858,000
Unamortized debt discount	-13,046,000	-13,046,000			-1,700,000	-13,046,000
Net carrying amount	98,812,000	98,812,000	0			98,812,000
Cash interest						6,264,000
PIK interest						1,691,000
Total interest cost						7,955,000
Early Payment Premium Percentage
Percent of Principal, Prior to First Anniversary					43.80%
Percent of Principal, Prior to Second Anniversary					33.70%
Percent of Principal, Prior to Third Anniversary					23.00%
Percent of Principal, Prior to Fourth Anniversary					11.50%
Percent of Principal, After to Fourth Anniversary					3.00%
Resulting from an Asset Sale, Percent of Principal					3.00%
Secured Debt | Parent Term Loan
Debt Instrument [Line Items]
Proceeds from issuance of secured debt					50,200,000
Unused borrowing capacity, amount					134,800,000
Unused borrowing, availability contingent upon achieving performance targets					50,000,000
Proceeds from issuance of secured debt including unused borrowing capacity, amount					185,000,000
Condition to be met for two consecutive fiscal quarters, Minimum EBITDA					20,000,000
Condition to be met, production equal to or greater than					4,000
Secured Debt | Magnequench Term Loan
Debt Instrument [Line Items]
Proceeds from issuance of secured debt					60,000,000
Unused borrowing capacity, amount					15,000,000
Unused borrowing, availability contingent upon achieving performance targets					5,000,000
Proceeds from issuance of secured debt including unused borrowing capacity, amount					75,000,000
Secured Debt | 12.00% Equipment Financing, due September 2019
Debt Instrument [Line Items]
Interest Rate, Stated Percentage					12.00%
Proceeds from issuance of secured debt					139,800,000
Interest rate, stated percentage, payment in cash					7.00%
Interest rate, stated percentage, (PIK) interest					5.00%
Debt Instrument, Term					5 years
Principal amount	141,993,000	141,993,000				141,993,000
Unamortized debt discount	-14,399,000	-14,399,000				-14,399,000
Net carrying amount	127,594,000	127,594,000	0			127,594,000
Cash interest						2,082,000
PIK interest						2,160,000
Total interest cost						4,242,000
Minimum Lease Payments, Sale Leaseback Transactions, Fiscal Year Maturity
Next Twelve Months					10,100,000
Within Two Years					10,700,000
Within Three Years					11,200,000
Within Four Years					11,800,000
Within Five Years					12,400,000
Sale leaseback transactions, Possible Payment Adjustment, Years Two Through Five					18,000,000
Sale leaseback transactions, Possible Payment Adjustment, Additional Payment on Five-Year Anniversary					147,000,000
Sale leaseback transactions, Additional Payment on Five-Year Anniversary					179,900,000
Convertible Debt
Debt Instrument [Line Items]
Gain (loss) on extinguishment of debt		-2,000,000
Convertible Debt | 3.25% Convertible Notes, net of discount, due June 2016
Debt Instrument [Line Items]
Interest Rate, Stated Percentage	3.25%	3.25%	3.25%			3.25%		3.25%
Repayments of convertible debt					23,700,000		23,500,000
Carrying amount, aggregate amount of principal to be paid down					40,000,000
Principal amount	206,505,000	206,505,000	230,000,000			206,505,000
Unamortized debt discount	-12,956,000	-12,956,000	-22,972,000			-12,956,000
Net carrying amount	193,549,000	193,549,000	207,028,000			193,549,000
Cash interest		15,553,000	15,839,000	15,312,000
Convertible Debt | 6.00% Convertible Notes, net of discount, due September 2017
Debt Instrument [Line Items]
Interest Rate, Stated Percentage	6.00%	6.00%	6.00%	6.00%		6.00%			6.00%
Repayments of convertible debt					4,000,000		4,000,000
Gain (loss) on extinguishment of debt	15,400,000
Carrying amount, aggregate amount of principal to be paid down					80,000,000
Principal amount	383,000,000	383,000,000	414,000,000			383,000,000
Unamortized debt discount	-47,031,000	-47,031,000	-67,292,000			-47,031,000
Net carrying amount	335,969,000	335,969,000	346,708,000			335,969,000
Cash interest		41,070,000	39,779,000	17,457,000
Convertible Debt | 5.50% Convertible Notes, net of discount, due February 2018
Debt Instrument [Line Items]
Interest Rate, Stated Percentage	5.50%	5.50%	5.50%			5.50%				5.50%
Gain (loss) on extinguishment of debt	6,300,000
Carrying amount, aggregate amount of principal to be paid down					40,000,000
Principal amount	161,500,000	161,500,000	172,500,000			161,500,000
Unamortized debt discount	-17,919,000	-17,919,000	-24,302,000			-17,919,000
Net carrying amount	143,581,000	143,581,000	148,198,000			143,581,000
Cash interest		$14,578,000	$13,107,000

Debt_and_Capital_Lease_Obligat7

Debt and Capital Lease Obligations - 2013 Debt Issuance (Details) (USD $)	1 Months Ended	3 Months Ended	12 Months Ended			0 Months Ended
	Nov. 30, 2014	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jan. 30, 2013
						D
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$1,700,000,000	$1,700,000,000
Debt Conversion, Converted Instrument, Shares Issued	15,100,000	15,056,603
Gain on extinguishment of convertible notes, net		19,719,000	19,719,000	0	0
Convertible Debt
Debt Instrument [Line Items]
Gain on extinguishment of convertible notes, net			-2,000,000
Convertible Debt | 5.50% Convertible Notes, net of discount, due February 2018
Debt Instrument [Line Items]
Debt Instrument, Face Amount		11,000,000	11,000,000			150,000,000
Interest Rate, Stated Percentage		5.50%	5.50%	5.50%		5.50%
Debt Instrument, Face Amount, Underwriter Option to Purchase Additional Principal						22,500,000
Proceeds from Issuance of Long-term Debt						165,600,000
Debt Instrument, Convertible, Conversion Ratio						138.8889
Debt Instrument, Convertible, Conversion Price						$7.20
Debt Instrument, Threshold Percentage Above Which Company Has Right To Redeem Notes						130.00%
Debt Instrument, Convertible, Threshold Trading Days						20
Debt Instrument, Convertible, Threshold Consecutive Trading Days						30 days
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt				21,815,000
Debt Conversion, Converted Instrument, Shares Issued		4,358,490
Gain on extinguishment of convertible notes, net		6,300,000
Goodwill		1,200,000	1,200,000
Convertible Debt | 5.50% Convertible Notes, net of discount, due February 2018 | Additional Paid-In Capital
Debt Instrument [Line Items]
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt			21,815	21,815,000		21,800,000
Convertible Debt | 5.50% Convertible Notes, net of discount, due February 2018 | Officers, Directors and Other Related Parties
Debt Instrument [Line Items]
Proceeds from Related Party Debt						$20,500,000

Debt_and_Capital_Lease_Obligat8

Debt and Capital Lease Obligations - 2012 Debt Issuances and Assumed Liabilities (Details) (USD $)	0 Months Ended		1 Months Ended	3 Months Ended	12 Months Ended			0 Months Ended		1 Months Ended		0 Months Ended
	Oct. 21, 2013	Jan. 30, 2013	Nov. 30, 2014	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 11, 2014	Aug. 22, 2012	Sep. 30, 2014	Aug. 31, 2012	25-May-12	Dec. 31, 2011	Jun. 12, 2012
									D
Debt Instrument [Line Items]
Debt Instrument, Face Amount				$1,700,000,000	$1,700,000,000
Debt Conversion, Converted Instrument, Shares Issued			15,100,000	15,056,603
Gain on extinguishment of convertible notes, net				19,719,000	19,719,000	0	0
Goodwill				102,808,000	102,808,000	228,750,000	239,742,000						3,432,000
Repayments of convertible debt					27,495,000	0	0
Issuance of shares (in shares)	51,750,000	37,500,000
Senior Notes | 10% Senior Secured Notes due June 2020
Debt Instrument [Line Items]
Interest Rate, Stated Percentage				10.00%	10.00%	10.00%						10.00%
Convertible Debt
Debt Instrument [Line Items]
Gain on extinguishment of convertible notes, net					-2,000,000
Convertible Debt | 6.00% Convertible Notes, net of discount, due September 2017
Debt Instrument [Line Items]
Interest Rate, Stated Percentage				6.00%	6.00%	6.00%	6.00%		6.00%
Debt Instrument, Face Amount				27,000,000	27,000,000				360,000,000
Debt Instrument, Face Amount, Underwriter Option to Purchase Additional Principal									54,000,000
Proceeds from Issuance of Long-term Debt									395,700,000
Proceeds from Related Party Debt									6,400,000
Debt Instrument, Convertible, Conversion Ratio									83.333
Debt Instrument, Convertible, Conversion Price									$12
Debt Instrument, Threshold Percentage Above Which Company Has Right To Redeem Notes									130.00%
Debt Instrument, Convertible, Threshold Trading Days									20
Debt Instrument, Convertible, Threshold Consecutive Trading Days									30 days
Redemption price of principal amount									100.00%
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt							68,695,000
Debt Conversion, Converted Instrument, Shares Issued				10,698,113
Gain on extinguishment of convertible notes, net				15,400,000
Difference between consideration transferred to the holder and the fair value of liability component				3,500,000	3,500,000
Repayments of convertible debt								4,000,000		4,000,000
Convertible Debt | 6.00% Convertible Notes, net of discount, due September 2017 | Common Stock
Debt Instrument [Line Items]
Issuance of shares (in shares)											13,800,000
Convertible Debt | Additional Paid-In Capital | 6.00% Convertible Notes, net of discount, due September 2017
Debt Instrument [Line Items]
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt					68,695		68,695,000
Convertible Subordinated Debt | 5.00% Debentures, net of discount, due December 2017
Debt Instrument [Line Items]
Interest Rate, Stated Percentage				5.00%	5.00%									5.00%
Debt Instrument, Face Amount														230,000,000
Debt Instrument, Convertible, Conversion Price														$13.80
Aggregate principal amount											9,400,000
Debt Instrument, Repurchased Face Amount											217,900,000
Debt Instrument, Repurchase Amount											8,000,000
Convertible Subordinated Debt | 5.00% Debentures, net of discount, due December 2017 | Common Stock
Debt Instrument [Line Items]
Issuance of shares (in shares)											99,723
Secured Debt | Before June 1, 2016
Debt Instrument [Line Items]
Debt Instrument, Redeemable Debt, Redemption Percentage of Principal Amount												100.00%
Secured Debt | After June 1, 2016
Debt Instrument [Line Items]
Debt Instrument, Redeemable Debt, Redemption Percentage of Principal Amount												105.00%
Secured Debt | Before June 1, 2015
Debt Instrument [Line Items]
Debt Instrument, Redeemable Debt, Redeemable Principal from Proceeds from Equity												35.00%
Debt Instrument, Redeemable Debt, Redeemable Percentage of Principal from Proceed from Equity												110.00%
Secured Debt | 10% Senior Secured Notes due June 2020
Debt Instrument [Line Items]
Debt Instrument, Face Amount												650,000,000
Proceeds from Issuance of Long-term Debt												635,400,000
Debt Instrument, Collateral, Excluded Assets, Asset Fair Market Value, Maximum												15,000,000
Debt Instrument, Collateral, Excluded Assets, Cash Collateral for Line of Credits or Hedging Obligations, Maximum												105.00%
Debt Instruments, Collateral, Excluded Assets, Voting Stock of Foreign Subsidiaries, Percent, Minimum												65.00%

Debt_and_Capital_Lease_Obligat9

Debt and Capital Lease Obligations - 2011 Debt Issuance (Details) (USD $)	12 Months Ended			0 Months Ended		1 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 11, 2014	Jun. 15, 2011	Sep. 30, 2014
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$1,700,000,000
Repayments of convertible debt	27,495,000	0	0
Convertible Debt | 3.25% Convertible Notes, net of discount, due June 2016
Debt Instrument [Line Items]
Interest Rate, Stated Percentage	3.25%	3.25%			3.25%
Debt Instrument, Face Amount					230,000,000
Proceeds from Issuance of Long-term Debt					223,100,000
Debt Instrument, Convertible, Conversion Ratio					14.0056
Debt Instrument, Convertible, Conversion Price					$71.40
Repayments of convertible debt				23,700,000		23,500,000
Convertible Debt | 3.25% Convertible Notes, net of discount, due June 2016 | Additional Paid-In Capital
Debt Instrument [Line Items]
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt	$36,227				$36,200,000

Recovered_Sheet1

Debt and Capital Lease Obligations - Capital Leases (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Debt Disclosure [Abstract]
2015	$8,276
2016	8,276
2017	7,159
2018	5,769
2019	5,488
Thereafter	12,706
Total	47,674
Imputed interest included in total future minimum lease payments at December 31, 2014	$22,655

Income_Taxes_Narrative_Details

Income Taxes - Narrative (Details) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Goodwill, Impairment Loss	$125,900,000	$125,942,000	$10,992,000	$289,894,000
Deferred tax liabilities, net	54,496,000	54,496,000	85,416,000
Valuation allowance	252,291,000	252,291,000	107,358,000
Unrecognized Tax Benefits, Period Increase (Decrease)		1,200,000
Effective income tax rate		3.70%	16.40%	10.30%
Foreign subsidiary earnings and withholding taxes	10,423,000	10,423,000	14,804,000
Deferred income tax expense due to elimination of intercompany balances and transactions	1,400,000	1,400,000
Income tax payable due to elimination of intercompany balances and transactions	0	0
Tax credit carryforward	7,300,000	7,300,000
IRS
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Operating Loss Carryforwards	538,000,000	538,000,000
State
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Operating Loss Carryforwards	436,900,000	436,900,000
Foreign Tax Authority
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Operating Loss Carryforwards	231,800,000	231,800,000
Indefinite Carryforward
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Tax credit carryforward	2,200,000	2,200,000
Expiring between 2028 and 2032
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Tax credit carryforward	5,100,000	5,100,000
Expiring in 2023
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Operating Loss Carryforwards	$28,600,000	$28,600,000

Income_Taxes_Schedule_of_Compo

Income Taxes - Schedule of Components of Income Tax Expense (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current
Federal	$0	($2,581)	($22,418)
Foreign	16,532	-1,018	8,994
State	-130	792	-4,197
Total current	16,402	-2,807	-17,621
Deferred
Federal	-8,111	-43,479	-20,786
Foreign	-29,366	-16,517	-11,777
State	-1,519	-8,140	-3,891
Total deferred	-38,996	-68,136	-36,454
Total tax benefit	($22,594)	($70,943)	($54,075)

Income_Taxes_Schedule_of_Incom

Income Taxes - Schedule of Income before Income Tax, Domestic and Foreign (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
United States									($415,381)	($286,818)	($161,129)
Foreign									-203,384	-145,458	-363,062
Loss from continuing operations before income taxes and equity earnings	($343,375)	($99,484)	($89,724)	($86,182)	($228,592)	($76,181)	($70,254)	($57,249)	($618,765)	($432,276)	($524,191)

Income_Taxes_Schedule_of_Effec

Income Taxes - Schedule of Effective Income Tax Reconciliation (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		35.00%	35.00%
Federal tax computed at the statutory rate	($216,568)	($151,297)	($184,075)
State taxes, net of federal benefit	-16,609	-10,329	-5,970
Change in valuation allowance	148,187	85,881	19,515
Impairment of goodwill and other long-lived assets	48,250	7,458	103,563
Changes related to uncertain tax positions	1,220	-5,153	-14,176
Federal and State tax credits	0	2,946	-6,817
Foreign income tax rate differential	12,956	24,315	18,682
Foreign translation adjustments	-11,968	-7,744	0
Change in applicable law	0	-5,884	0
Other items, net	11,938	-11,136	15,203
Total tax benefit	($22,594)	($70,943)	($54,075)

Income_Taxes_Schedule_of_Defer

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current:
Inventory	$30,487	$2,570
Other	1,499	2,605
Total current	31,986	5,175
Non-current:
Asset retirement obligation	3,705	0
Mineral resources	16,832	16,886
Property, plant and equipment and intangible assets	3,451	21,044
Stock compensation	2,805	1,964
Net operating losses	255,588	144,366
Research and energy tax credits and expenditures	6,141	6,233
Alternative Minimum Tax Credit	2,216	2,216
Unrealized foreign exchange	17,380	5,664
Investments	0	3,120
Other	5,675	4,107
Total non-current	313,793	205,600
Current
Inventory	0	1,312
Other	1,680	1,423
Total current	1,680	2,735
Non-current:
Asset retirement obligation	0	1,190
Foreign subsidiary earnings and withholding taxes	10,423	14,804
Property, plant, equipment and intangible assets	100,076	125,527
Convertible debt (Notes), share lending and other financing arrangements	35,722	44,275
Other	83	302
Total non-current	146,304	186,098
Net deferred taxes, before valuation allowance	197,795	21,942
Valuation allowance	-252,291	-107,358
Total deferred tax	($54,496)	($85,416)

Income_Taxes_Reconciliation_of

Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance, beginning of year	$1,066	$6,219	$519
Tax position related to current year:
Additions	1,220	0	4,737
Tax positions related to prior years:
Additions	0	0	16,109
Settlements	0	-4,737	-13,740
Statute of limitations closures	0	-416	-1,406
Balance, end of year	$2,286	$1,066	$6,219

Stockholders_Equity_Exchange_o

Stockholders' Equity - Exchange of Convertible Notes (Details) (USD $)	1 Months Ended	3 Months Ended	12 Months Ended
	Nov. 30, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jan. 30, 2013	Aug. 22, 2012
Debt Conversion [Line Items]
Debt Conversion, Converted Instrument, Shares Issued	15,100,000	15,056,603
Debt Instrument, Face Amount		$1,700,000,000
Deferred taxes on component of convertible debt		16,400,000	-8,508,000	-27,106,000
Goodwill		102,808,000	228,750,000	239,742,000	3,432,000
Convertible Senior Notes, 5.50% and 6.00%
Debt Conversion [Line Items]
Difference between consideration transferred to the holder and the fair value of liability component		4,800,000
5.50% Convertible Notes, net of discount, due February 2018 | Convertible Debt
Debt Conversion [Line Items]
Interest Rate, Stated Percentage		5.50%	5.50%			5.50%
Debt Conversion, Converted Instrument, Shares Issued		4,358,490
Debt Instrument, Face Amount		11,000,000				150,000,000
Difference between consideration transferred to the holder and the fair value of liability component		1,200,000
6.00% Convertible Notes, net of discount, due September 2017 | Convertible Debt
Debt Conversion [Line Items]
Interest Rate, Stated Percentage		6.00%	6.00%	6.00%			6.00%
Debt Conversion, Converted Instrument, Shares Issued		10,698,113
Debt Instrument, Face Amount		27,000,000					360,000,000
Difference between consideration transferred to the holder and the fair value of liability component		$3,500,000

Stockholders_Equity_Issuance_o

Stockholders' Equity - Issuance of Warrants (Details) (USD $)	0 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 11, 2014	Sep. 11, 2014
Class of Warrant or Right [Line Items]
Number of securities called by warrants	24,477,359	24,477,359
Penny Warrants
Class of Warrant or Right [Line Items]
Number of securities called by warrants	18,358,019	18,358,019
Strike price	$0.01	$0.01
Warrants and Rights Outstanding	$24.70	$24.70
Payments of Stock Issuance Costs	1.5
Term (years)	5 years
Stock price	$1.55	$1.55
Risk-free interest rate	1.79%
Volatility	82.60%
Dividend yield	0.00%
Fair Value Inputs, Discount for Lack of Marketability	9.00%
Fair Value Assumptions, Application of Discount for Lack of Marketability, Share Price	$1.40	$1.40
Strike Warrants
Class of Warrant or Right [Line Items]
Number of securities called by warrants	6,119,340	6,119,340
Strike price	$2.04	$2.04
Warrants and Rights Outstanding	$3.50	$3.50
Term (years)	5 years
Stock price	$1.55	$1.55
Risk-free interest rate	1.79%
Volatility	49.90%
Dividend yield	0.00%
Fair Value Inputs, Discount for Lack of Marketability	31.00%
Fair Value Assumptions, Application of Discount for Lack of Marketability, Share Price	$0.57	$0.57

Stockholders_Equity_Conversion

Stockholders' Equity - Conversion of Preferred Stock (Details) (USD $)	12 Months Ended			0 Months Ended		24 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 01, 2014	Feb. 16, 2011	Dec. 31, 2013
Class of Stock [Line Items]
Payments of Ordinary Dividends, Preferred Stock and Preference Stock	$2,846	$11,385	$11,385
Series A Mandatory Convertible Preferred Stock
Class of Stock [Line Items]
Preferred Stock, Dividend Rate, Percentage				5.50%
Mandatory Convertible Preferred Stock Price Per Share					$100
Preferred Stock, Shares Outstanding		2,070,000				2,070,000
Payments of Ordinary Dividends, Preferred Stock and Preference Stock				$2,800		$11,400
Preferred Stock, Dividends Per Share, Declared						$1.38
Common Stock
Class of Stock [Line Items]
Convertible Preferred Stock, Shares Issued upon Conversion, Conversion Rate				2
Convertible Preferred Stock, Shares Issued upon Conversion				4,140,000

Stockholders_Equity_ShareLendi

Stockholders' Equity - Share-Lending Arrangements (Details) (USD $)	12 Months Ended			3 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2014	Jan. 31, 2013	Aug. 31, 2012
Debt Conversion [Line Items]
Fair value	$5,219
Increase to balance sheet captions:
Other non-current assets	29,416	7,043
Property, plant and equipment, net	1,707,970	1,762,874
Additional paid-in capital	2,245,478	2,194,405
Increase to statements of operations and comprehensive loss captions:
Interest expense, net of capitalized interest	167,375	67,684	22,116
Income tax benefit	22,594	70,943	54,075
Own-share Lending Arrangement [Abstract]
Interest cost expensed	7,445
Interest cost capitalized	3,378
Unamortized issuance cost	13,868
Deferred Finance Costs, Own-share Lending Arrangement, Issuance Costs, Amortization Expense	10,823
Own-share Lending Arrangement | Restatement Adjustment
Increase to balance sheet captions:
Other non-current assets				16,381
Property, plant and equipment, net				3,378
Additional paid-in capital				15,062
Increase to statements of operations and comprehensive loss captions:
Interest expense, net of capitalized interest				4,933
Income tax benefit				9,630
Common Stock
Debt Conversion [Line Items]
Own-share Lending Arrangement, Shares, Outstanding					6,666,666	13,800,000
6.00% Convertible Notes, net of discount, due September 2017 | Convertible Debt Securities
Debt Conversion [Line Items]
Fair value	3,329					18,100
Own-share Lending Arrangement [Abstract]
Unamortized issuance cost	9,694
5.50% Convertible Notes, net of discount, due February 2018 | Convertible Debt Securities
Debt Conversion [Line Items]
Fair value	1,890				6,600
Own-share Lending Arrangement [Abstract]
Unamortized issuance cost	$4,174

Stockholders_Equity_2013_Publi

Stockholders' Equity - 2013 Public Equity Issuance (Details) (USD $)	0 Months Ended		1 Months Ended	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Oct. 21, 2013	Jan. 30, 2013	Aug. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Aug. 23, 2012
Class of Stock [Line Items]
Issuance of shares (in shares)	51,750,000	37,500,000
Shares Issued During Period, Shares, New Issues, Underwriters Option to Purchase within 30 days	6,750,000	5,625,000
Offering Price Per Share, Underwriters	$5	$6
Shares Issued During Period, Shares, New Issues, Underwriter Fees	5.00%	6.00%
Shares Issued During Period, Shares, New Issues, Purchased by Related Parties	14,034,000
Net proceeds from sale of common stock	$247,500	$248,100	$132,100	$0	$495,717	$132,130
Offering Price Per Share		$6
Own-share Lending Arrangement, Shares, Maximum Shares Allowed		7,666,666
Own-share Lending Arrangement, Shares, Issued, Offered in Registered Public Offering, Price Per Share		$6
Common Stock
Class of Stock [Line Items]
Own-share Lending Arrangement, Shares, Issued		6,666,666					13,800,000
Convertible Debt | 5.50% Convertible Notes, net of discount, due February 2018
Class of Stock [Line Items]
Interest Rate, Stated Percentage		5.50%		5.50%	5.50%
Officers, Directors and Other Related Parties
Class of Stock [Line Items]
Shares Issued During Period, Shares, New Issues, Purchased by Related Parties		15,016,666

Stockholders_Equity_2012_Equit

Stockholders' Equity - 2012 Equity Issuance (Details) (USD $)	0 Months Ended		1 Months Ended		12 Months Ended			0 Months Ended		1 Months Ended	31 Months Ended	0 Months Ended	3 Months Ended
	Oct. 21, 2013	Jan. 30, 2013	Aug. 31, 2012	Jun. 30, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 08, 2012	Jun. 11, 2012	Jun. 30, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Aug. 23, 2012	Aug. 22, 2012	Jun. 12, 2012
Class of Stock [Line Items]
Property, plant and equipment at cost					$1,900,310,000	$1,865,552,000					1,900,310,000	$1,865,552,000
Payments to acquire exploration rights					0	0	8,167,000
Tangible Asset Impairment Charges					14,400,000	16,300,000	5,900,000
Issuance of shares (in shares)	51,750,000	37,500,000
Net proceeds from sale of common stock	247,500,000	248,100,000	132,100,000		0	495,717,000	132,130,000
Fair value of Molycorp common stock and Exchangeable Shares issued				284,100,000
Stock Issued During Period, Value, New Issues						247,567,000
Molymet
Class of Stock [Line Items]
Issuance of shares (in shares)								12,500,000
Stock Issued During Period, Value, New Issues							390,093,000	390,100,000
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs								100,000
Price Per Share of Common Stock Issued								$31.22
Number of Days to Calculate Common Stock Price								20 days
Premium Percentage Added to Common Stock Price								10.00%
Molycorp
Class of Stock [Line Items]
Common stock issued to acquire the entity (in shares)									13,545,426
MCP Exchangeco Inc.
Class of Stock [Line Items]
Common stock issued to acquire the entity (in shares)										507,203
Common Stock
Class of Stock [Line Items]
Stock price			$10
Underwriting discounts and commissions			6.00%
Flat fee paid to underwriters			1,500,000
Primary shares purchased by insiders			7,090,000
Own-share Lending Arrangement, Shares, Issued		6,666,666												13,800,000
Conversion of Exchangeable Shares											380,648
Common Stock | Molycorp
Class of Stock [Line Items]
Conversion of Exchangeable Shares					105,419
6.00% Convertible Notes, net of discount, due September 2017 | Convertible Debt
Class of Stock [Line Items]
Interest Rate, Stated Percentage					6.00%	6.00%	6.00%				6.00%	6.00%	6.00%		6.00%
6.00% Convertible Notes, net of discount, due September 2017 | Convertible Debt | Common Stock
Class of Stock [Line Items]
Issuance of shares (in shares)			13,800,000
5.00% Debentures, net of discount, due December 2017 | Convertible Subordinated Debt
Class of Stock [Line Items]
Interest Rate, Stated Percentage					5.00%						5.00%					5.00%
5.00% Debentures, net of discount, due December 2017 | Convertible Subordinated Debt | Common Stock
Class of Stock [Line Items]
Issuance of shares (in shares)			99,723
Exploration rights
Class of Stock [Line Items]
Property, plant and equipment at cost							16,200,000						16,200,000
Issuance of shares for acquisition of exploration rights (in shares)													788,410
Sale of Stock, Price Per Share							$10.15						$10.15
Payments to acquire exploration rights													8,200,000
Tangible Asset Impairment Charges												16,200,000
Common Stock
Class of Stock [Line Items]
Issuance of shares for acquisition of exploration rights (in shares)							788,410
Issuance of shares (in shares)						51,750,000
Conversion of Exchangeable Shares					21,836	18,616
Stock Issued During Period, Value, New Issues						52,000
Common Stock | Molymet
Class of Stock [Line Items]
Issuance of shares (in shares)							12,500,000
Stock Issued During Period, Value, New Issues							$12,000
Common Stock | 6.00% Convertible Notes, net of discount, due September 2017
Class of Stock [Line Items]
Issuance of shares for conversion of Debentures (in shares)					10,698,113
Common Stock | Convertible Debt Securities
Class of Stock [Line Items]
Issuance of shares for conversion of Debentures (in shares)						2,471	99,723
Common Stock | Convertible Debt Securities | 5.00% Debentures, net of discount, due December 2017 | Convertible Subordinated Debt | Common Stock
Class of Stock [Line Items]
Issuance of shares for conversion of Debentures (in shares)					3,225	2,471

Stockholders_Equity_Accumulate

Stockholders' Equity - Accumulated Other Comprehensive Income (Loss) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	($6,451)	($9,433)	($8,481)
Change in other comprehensive loss before reclassifications	3,128	2,982	-952
Net income (loss) reclassified from AOCI	0	0	0
Ending balance	-3,323	-6,451	-9,433
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	-6,610	-8,233	-8,481
Change in other comprehensive loss before reclassifications	4,271	1,623	248
Net income (loss) reclassified from AOCI	0	0	0
Ending balance	-2,339	-6,610	-8,233
Postretirement benefit liability
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	159	-1,200	0
Change in other comprehensive loss before reclassifications	-1,143	1,359	-1,200
Net income (loss) reclassified from AOCI	0	0	0
Ending balance	($984)	$159	($1,200)

Loss_per_Share_Details

Loss per Share (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Earnings Per Share [Abstract]
Net loss attributable to Molycorp stockholders	($329,795)	($105,179)	($83,899)	($86,061)	($194,308)	($69,929)	($71,175)	($38,971)	($604,934)	($374,383)	($481,169)
Dividends on Convertible Preferred Stock									-2,846	-11,385	-11,385
Loss attributable to common stockholders									-607,780	-385,768	-492,554
Continuing operations									-607,780	-379,341	-490,817
Discontinued operations									$0	($6,427)	($1,737)
Weighted average common shares outstanding—basic									224,978,752	174,528,717	107,064,892
Basic loss per share from:
Continuing operations (in dollars per share)									($2.70)	($2.17)	($4.58)
Discontinued operations (in dollars per share)									$0	($0.04)	($0.02)
Basic (in dollars per share)	($1.43)	($0.47)	($0.37)	($0.40)	($0.95)	($0.43)	($0.44)	($0.27)	($2.70)	($2.21)	($4.60)
Weighted average common shares outstanding—diluted									224,978,752	174,528,717	107,064,892
Diluted loss per share from:
Continuing operations (in dollars per share)									($2.70)	($2.17)	($4.58)
Discontinued operations (in dollars per share)									$0	($0.04)	($0.02)
Diluted (in dollars per share)	($1.43)	($0.47)	($0.37)	($0.40)	($0.95)	($0.43)	($0.44)	($0.27)	($2.70)	($2.21)	($4.60)

StockBased_Compensation_Narrat

Stock-Based Compensation - Narrative (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	26,616
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	48.87
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant	3,930,494
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	3 years
Matching contribution by entity (as a percent)	25.00%
PBRSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	3 years
PBRSUs | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of units vesting	0.00%
PBRSUs | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of units vesting	150.00%
RSAs, RSUs and PBRSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost not yet recognized	11.2
Weighted-average period for unrecognized compensation costs	1 year 9 months 11 days

StockBased_Compensation_Alloca

Stock-Based Compensation - Allocation of Recognized Period Costs (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-based compensation expense	$5,261	$5,392	$3,434

StockBased_Compensation_Activi

Stock-Based Compensation - Activity Related to Restricted Stock-based Awards (Details) (USD $)	12 Months Ended
	Dec. 31, 2014
PBRSUs
Number of Shares
Unvested at the beginning of the period (in shares)	697,797
Granted (in shares)	975,505
Forfeited (in shares)	-41,240
Vested (in shares)	-18,246
Unvested at the end of the period (in shares)	1,613,816
Weighted Average Grant-Date Price
Unvested shares at the beginning of the period (in dollars per share)	$7.45
Granted (in dollars per share)	$4.22
Forfeited (in dollars per share)	$6.66
Vested (in dollars per share)	$30.33
Unvested shares at the end of the period (in dollars per share)	$5.28
RSUs
Number of Shares
Unvested at the beginning of the period (in shares)	1,076,385
Granted (in shares)	1,165,497
Forfeited (in shares)	-71,399
Vested (in shares)	-70,998
Unvested at the end of the period (in shares)	2,099,485
Weighted Average Grant-Date Price
Unvested shares at the beginning of the period (in dollars per share)	$9.81
Granted (in dollars per share)	$3.86
Forfeited (in dollars per share)	$8.71
Vested (in dollars per share)	$22.98
Unvested shares at the end of the period (in dollars per share)	$6.10
Restricted Stock
Number of Shares
Unvested at the beginning of the period (in shares)	6,326
Granted (in shares)	0
Forfeited (in shares)	0
Vested (in shares)	0
Unvested at the end of the period (in shares)	6,326
Weighted Average Grant-Date Price
Unvested shares at the beginning of the period (in dollars per share)	$55.05
Granted (in dollars per share)	$0
Forfeited (in dollars per share)	$0
Vested (in dollars per share)	$0
Unvested shares at the end of the period (in dollars per share)	$55.05

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
PBRSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other Than Options, Grants in Period, Weighted Average Grant Date Fair Value, Total	$4,117	$6,139	$1,382
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other Than Options, Grants in Period, Weighted Average Grant Date Fair Value, Total	$4,499	$7,060	$5,540

Commitments_and_Contingencies_1

Commitments and Contingencies - Operating Leases (Details) (Office space, trailers and certain equipment, USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Office space, trailers and certain equipment
Remaining annual minimum payments under operating leases
Operating lease obligations, total minimum payments	$6,661,000
Operating lease obligations, Less Than 1 Year	2,380,000
Operating lease obligations, 1 -3 Years	3,012,000
Operating lease obligations, 4 - 5 Years	508,000
Operating lease obligations, More Than 5 Years	761,000
Operating leases rent expense net	$3,100,000	$4,000,000	$4,100,000

Commitments_and_Contingencies_2

Commitments and Contingencies - Purchase Commitments (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]
Purchase obligations and other commitment, Total	$8,187
Purchase obligations and other commitment, Less Than 1 Year	0
Purchase obligations and other commitment, 1 - 3 Years	8,187
Purchase obligations and other commitment, 4 - 5 Years	0
Purchase obligations and other commitment, More Than Five Years	$0

Commitments_and_Contingencies_3

Commitments and Contingencies - Narrative (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Aug. 31, 2012	Jul. 31, 2012	Aug. 31, 2013
	employee	lawsuit	claim	lawsuit
Plant Modernization and Expansion Commitments
Surety bonds placed to secure the closure and reclamation obligations	28.8
Consolidated Class Action
Plant Modernization and Expansion Commitments
Number of claims			18
Number of stockholder derivative lawsuits		2
Purported Class Action
Plant Modernization and Expansion Commitments
Number of stockholder derivative lawsuits				2
Workforce | Employees covered by collective bargaining agreement under facility | Molycorp Silmet
Plant Modernization and Expansion Commitments
Number of employees	155
Concentration risk (as a percent)	28.00%
Workforce | Employees covered by collective bargaining agreement under facility | Molycorp Mountain Pass facility
Plant Modernization and Expansion Commitments
Number of employees	282
Concentration risk (as a percent)	59.00%

Concentrations_Details

Concentrations (Details) (USD $)	12 Months Ended			7 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2012
Daido Electronics
Concentrations
Related party receivables	6.3	7.5
Cerium products | Product Concentration | Chemicals and Oxides
Concentrations
Entity-wide revenue, major customers	11.00%	9.00%	15.00%
Neo Powders | Daido Electronics
Concentrations
Sales to related party	62.3	56.5		$32.90
Neo Powders | Product Concentration | Magnetic Materials and Alloys
Concentrations
Entity-wide revenue, major customers	44.00%	41.00%	25.00%

RelatedParty_Transactions_Deta

Related-Party Transactions (Details) (USD $)	7 Months Ended	12 Months Ended		7 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
TMT | Neo Powders
Related Party Transactions
Sales to related party	$1.60	$6	$4.50
TMT | Compounds
Related Party Transactions
Purchases made from related party		2.3	2.1	2.8
Keli
Related Party Transactions
Accounts Payable, Related Parties		8.4
Keli | Metals
Related Party Transactions
Purchases made from related party	32.6	63.4	61.3
Ingal Stade | Gallium Metal
Related Party Transactions
Purchases made from related party	$3.30	$2.80	$4.90

Net_Change_in_Operating_Assets2

Net Change in Operating Assets and Liabilities (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Decrease (increase) in operating assets:
Trade accounts receivable	$17,169	($8,986)	$124,983
Inventory	-82,390	15,649	-46,126
Prepaid expenses and other assets	-4,299	-5,728	33,520
Increase (decrease) in operating liabilities:
Accounts payable	-14,028	-24,177	-34,972
Income tax payable	2,271	18,966	-40,263
Interest payable	30,181	-39,120	-40,792
Asset retirement obligation	-1,606	-7,642	-1,467
Accrued expenses	3,918	-13,681	-54,763
Net change in operating assets and liabilities	($48,784)	($64,719)	($59,880)

Supplemental_Cash_Flow_Informa2

Supplemental Cash Flow Information (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net cash paid for:
Income taxes	$13,976	($13,429)	$178
Interest, net of capitalized interest	112,575	32,833	8,942
Non-cash financing activities and investing activities:
Change in accrued capital expenditures	28,501	58,673	52,189
Conversion of debt securities to equity securities	38,000	18	4,527
Acquisition of exploration rights	0	0	8,000
Debt assumed from business acquisitions	0	0	40,691
Issuance of common stock for business acquisitions	0	0	284,100
Fixed assets additions under capital lease	$3,612	$7,370	$15,658

Fair_Value_of_Financial_Instru2

Fair Value of Financial Instruments - Measured at Fair Value on a Recurring Basis (Details) (Fair Value, Measurements, Recurring, USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Level 1
Assets:
Cash equivalents	$57,309	$179,052
Liabilities:
Derivative liabilities		0
Level 1 | Springing Maturity on Term Loans
Liabilities:
Derivative liabilities	0
Level 1 | Strike Warrants
Liabilities:
Derivative liabilities	0
Level 1 | Share Purchase Agreement
Liabilities:
Derivative liabilities	0
Level 2
Assets:
Cash equivalents	0	0
Liabilities:
Derivative liabilities		0
Level 2 | Springing Maturity on Term Loans
Liabilities:
Derivative liabilities	0
Level 2 | Strike Warrants
Liabilities:
Derivative liabilities	0
Level 2 | Share Purchase Agreement
Liabilities:
Derivative liabilities	0
Level 3
Assets:
Cash equivalents	0	0
Liabilities:
Derivative liabilities		6,089
Level 3 | Springing Maturity on Term Loans
Liabilities:
Derivative liabilities	7,292
Level 3 | Strike Warrants
Liabilities:
Derivative liabilities	1,769
Level 3 | Share Purchase Agreement
Liabilities:
Derivative liabilities	$6,165

Fair_Value_of_Financial_Instru3

Fair Value of Financial Instruments - Liability Carrying and Fair Value (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Jun. 15, 2011	Dec. 31, 2012	Aug. 22, 2012	Jan. 30, 2013	25-May-12
In Thousands, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Excluding Current Maturities	$1,540,570	$1,344,561
3.25% Convertible Notes due June 2016 | Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Excluding Current Maturities	193,549	207,028
Interest Rate, Stated Percentage	3.25%	3.25%	3.25%
6.00% Convertible Notes due September 2017 | Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Excluding Current Maturities	335,969	346,708
Interest Rate, Stated Percentage	6.00%	6.00%		6.00%	6.00%
5.50% Convertible Notes due February 2018 | Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Excluding Current Maturities	143,581	148,198
Interest Rate, Stated Percentage	5.50%	5.50%				5.50%
10% Senior Secured Notes due June 2020 | Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Excluding Current Maturities	638,899	637,435
Interest Rate, Stated Percentage	10.00%	10.00%					10.00%
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Excluding Current Maturities	1,311,998	1,339,369
Carrying Amount | 3.25% Convertible Notes due June 2016 | Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Excluding Current Maturities	193,549	207,028
Carrying Amount | 6.00% Convertible Notes due September 2017 | Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Excluding Current Maturities	335,969	346,708
Carrying Amount | 5.50% Convertible Notes due February 2018 | Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Excluding Current Maturities	143,581	148,198
Carrying Amount | 10% Senior Secured Notes due June 2020 | Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Excluding Current Maturities	638,899	637,435
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	599,049	1,285,106
Fair Value | 3.25% Convertible Notes due June 2016 | Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	88,281	161,771
Fair Value | 6.00% Convertible Notes due September 2017 | Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	107,240	312,570
Fair Value | 5.50% Convertible Notes due February 2018 | Convertible Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	46,028	164,015
Fair Value | 10% Senior Secured Notes due June 2020 | Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	$357,500	$646,750

Fair_Value_of_Financial_Instru4

Fair Value of Financial Instruments - Narrative (Details)	Mar. 28, 2012	Jun. 11, 2012	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 11, 2014	Dec. 31, 2014
In Millions, unless otherwise specified	CAD	Other Expense	Level 3	Strike Warrants	Share Purchase Agreement	Share Purchase Agreement	12.00% Term Loans, due September 2019	Springing Maturity on Term Loans
		USD ($)	Derivative Liability	Interest Expense	Interest Expense	Interest Expense		Interest Expense
			Income Approach Valuation Technique	USD ($)	USD ($)	USD ($)		USD ($)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs, Probability Factor							10.00%
Gain (Loss) Included in Earnings				$1.70	$1.70	$1.20		($7.30)
Fair Value Inputs, Equity-risk Premium			6.00%
Fair Value Inputs, Risk Premium			11.50%
Fair Value Inputs, Size Premium			3.80%
Fair Value Inputs, Growth Rate			1.00%
Notional amount of derivatives	870
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net		($37.60)

Employee_Benefit_Plans_Narrati

Employee Benefit Plans - Narrative (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Company matching contribution as a percentage of the first 3.0% compensation contributed by each eligible employee	100.00%
Percentage of each employee's compensation eligible for Company match of 100% in defined contribution plan	3.00%
Company matching contribution as a percentage of the next 2.0% of compensation contributed by each eligible employee	50.00%
Percentage of each employee's compensation eligible for Company match of 50% in defined contribution plan	2.00%
Safe harbor matching contribution vesting percentage	100.00%
Vesting percentage of discretionary matching contribution after 3 years of service	100.00%
Period of service after which employees vest in Company contributions	3 years
Expenses related to defined contribution plan	$1.50	$2.90	$1.60
Defined contribution plan, accrued expense	0.6	1.9
Benefit obligation	8.7	7.6
Funded status of plan	-3.1	-2
Fair value of plan assets	5.6	5.6
Pension Plan and Other Postretirement Benefit Plan | Molycorp Canada | Anderson, Indiana Manufacturing Facility
Defined Benefit Plan Disclosure [Line Items]
Number of participants	289
Pension Plan | Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2.7
Pension Plan | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2.5
Pension Plan | Interest-bearing Deposits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$0.40

Subsidiary_Guarantor_Financial2

Subsidiary Guarantor Financial Information - Condensed Consolidating Balance Sheet (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$211,685	$314,317	$227,790	$418,855
Trade accounts receivable, net	44,575	61,757
Inventory	169,323	171,783
Prepaid expenses and other current assets	29,332	29,210
Total current assets	454,915	577,067
Non-current assets:
Deposits	31,078	25,997
Property, plant and equipment, net	1,707,970	1,762,874
Inventory	25,127	25,329
Intangible assets, net	215,871	330,867
Investments (Note 10)	8,801	48,875
Goodwill	102,808	228,750	239,742	3,432
Investments in consolidated subsidiaries	0	0
Intercompany accounts receivable	0	0
Other non-current assets	29,416	7,043
Total non-current assets	2,121,071	2,429,735
Total assets	2,575,986	3,006,802
Current liabilities:
Trade accounts payable	40,842	84,449
Accrued expenses	51,966	48,501
Debt and capital lease obligations	12,560	16,362
Other current liabilities	4,686	4,063
Total current liabilities	110,054	153,375
Non-current liabilities:
Asset retirement obligation	17,799	16,966
Deferred tax liabilities	63,802	85,481
Debt and capital lease obligations	1,559,781	1,363,916
Intercompany accounts payable	0	0
Other non-current liabilities	20,247	10,002
Total non-current liabilities	1,661,629	1,476,365
Total liabilities	1,771,683	1,629,740
Stockholders’ equity:
Common stock	260	241
Preferred stock	0	2
Additional paid-in capital	2,245,478	2,194,405
Accumulated other comprehensive loss	-3,323	-6,451	-9,433	-8,481
Accumulated deficit	-1,445,408	-840,474
Total Molycorp stockholders’ equity	797,007	1,347,723
Noncontrolling interests	7,296	29,339
Total stockholders’ equity	804,303	1,377,062	1,251,258	845,230
Total liabilities and stockholders’ equity	2,575,986	3,006,802
Parent
Current assets:
Cash and cash equivalents	98,650	169,145	16,560	407,446
Trade accounts receivable, net	0	0
Inventory	0	0
Prepaid expenses and other current assets	0	0
Total current assets	98,650	169,145
Non-current assets:
Deposits	1,756	1,754
Property, plant and equipment, net	0	0
Inventory	0	0
Intangible assets, net	0	0
Investments (Note 10)	0	0
Goodwill	0	0
Investments in consolidated subsidiaries	0	0
Intercompany accounts receivable	2,063,568	2,534,350
Other non-current assets	16,421	0
Total non-current assets	2,081,745	2,536,104
Total assets	2,180,395	2,705,249
Current liabilities:
Trade accounts payable	0	0
Accrued expenses	17,324	18,158
Debt and capital lease obligations	0	0
Other current liabilities	0	0
Total current liabilities	17,324	18,158
Non-current liabilities:
Asset retirement obligation	0	0
Deferred tax liabilities	0	0
Debt and capital lease obligations	1,357,003	1,339,368
Intercompany accounts payable	0	0
Other non-current liabilities	9,061	0
Total non-current liabilities	1,366,064	1,339,368
Total liabilities	1,383,388	1,357,526
Stockholders’ equity:
Common stock	260	241
Preferred stock		2
Additional paid-in capital	2,245,478	2,194,405
Accumulated other comprehensive loss	-3,323	-6,451
Accumulated deficit	-1,445,408	-840,474
Total Molycorp stockholders’ equity	797,007	1,347,723
Noncontrolling interests	0	0
Total stockholders’ equity	797,007	1,347,723
Total liabilities and stockholders’ equity	2,180,395	2,705,249
Guarantor Subsidiaries
Current assets:
Cash and cash equivalents	5,329	6,467	18,020	10,758
Trade accounts receivable, net	1,924	4,990
Inventory	36,956	32,307
Prepaid expenses and other current assets	9,673	15,833
Total current assets	53,882	59,597
Non-current assets:
Deposits	29,322	24,243
Property, plant and equipment, net	1,575,670	1,620,851
Inventory	25,127	25,329
Intangible assets, net	377	442
Investments (Note 10)	785	34,134
Goodwill	0	0
Investments in consolidated subsidiaries	91,672	104,327
Intercompany accounts receivable	0	0
Other non-current assets	7,792	771
Total non-current assets	1,730,745	1,810,097
Total assets	1,784,627	1,869,694
Current liabilities:
Trade accounts payable	14,641	49,702
Accrued expenses	16,256	13,782
Debt and capital lease obligations	3,234	2,234
Other current liabilities	263	617
Total current liabilities	34,394	66,335
Non-current liabilities:
Asset retirement obligation	17,799	16,966
Deferred tax liabilities	0	0
Debt and capital lease obligations	146,805	19,355
Intercompany accounts payable	2,134,041	1,999,562
Other non-current liabilities	1,424	1,393
Total non-current liabilities	2,300,069	2,037,276
Total liabilities	2,334,463	2,103,611
Stockholders’ equity:
Common stock	0	0
Preferred stock		0
Additional paid-in capital	132,335	132,335
Accumulated other comprehensive loss	0	0
Accumulated deficit	-682,171	-366,252
Total Molycorp stockholders’ equity	-549,836	-233,917
Noncontrolling interests	0	0
Total stockholders’ equity	-549,836	-233,917
Total liabilities and stockholders’ equity	1,784,627	1,869,694
Non-Guarantor Subsidiaries
Current assets:
Cash and cash equivalents	107,706	138,705	193,210	651
Trade accounts receivable, net	42,651	56,767
Inventory	132,367	139,476
Prepaid expenses and other current assets	19,659	13,377
Total current assets	302,383	348,325
Non-current assets:
Deposits	0	0
Property, plant and equipment, net	132,300	142,023
Inventory	0	0
Intangible assets, net	215,494	330,425
Investments (Note 10)	8,016	14,741
Goodwill	102,808	228,750
Investments in consolidated subsidiaries	0	0
Intercompany accounts receivable	0	0
Other non-current assets	5,203	6,272
Total non-current assets	463,821	722,211
Total assets	766,204	1,070,536
Current liabilities:
Trade accounts payable	26,201	34,747
Accrued expenses	18,386	16,561
Debt and capital lease obligations	9,326	14,128
Other current liabilities	4,423	3,446
Total current liabilities	58,336	68,882
Non-current liabilities:
Asset retirement obligation	0	0
Deferred tax liabilities	63,802	85,481
Debt and capital lease obligations	55,973	5,193
Intercompany accounts payable	658,986	783,011
Other non-current liabilities	9,762	8,609
Total non-current liabilities	788,523	882,294
Total liabilities	846,859	951,176
Stockholders’ equity:
Common stock	0	0
Preferred stock		0
Additional paid-in capital	534,440	534,436
Accumulated other comprehensive loss	-3,323	-6,451
Accumulated deficit	-619,068	-437,964
Total Molycorp stockholders’ equity	-87,951	90,021
Noncontrolling interests	7,296	29,339
Total stockholders’ equity	-80,655	119,360
Total liabilities and stockholders’ equity	766,204	1,070,536
Eliminations
Current assets:
Cash and cash equivalents	0	0	0	0
Trade accounts receivable, net	0	0
Inventory	0	0
Prepaid expenses and other current assets	0	0
Total current assets	0	0
Non-current assets:
Deposits	0	0
Property, plant and equipment, net	0	0
Inventory	0	0
Intangible assets, net	0	0
Investments (Note 10)	0	0
Goodwill	0	0
Investments in consolidated subsidiaries	-91,672	-104,327
Intercompany accounts receivable	-2,063,568	-2,534,350
Other non-current assets	0	0
Total non-current assets	-2,155,240	-2,638,677
Total assets	-2,155,240	-2,638,677
Current liabilities:
Trade accounts payable	0	0
Accrued expenses	0	0
Debt and capital lease obligations	0	0
Other current liabilities	0	0
Total current liabilities	0	0
Non-current liabilities:
Asset retirement obligation	0	0
Deferred tax liabilities	0	0
Debt and capital lease obligations	0	0
Intercompany accounts payable	-2,793,027	-2,782,573
Other non-current liabilities	0	0
Total non-current liabilities	-2,793,027	-2,782,573
Total liabilities	-2,793,027	-2,782,573
Stockholders’ equity:
Common stock	0	0
Preferred stock		0
Additional paid-in capital	-666,775	-666,771
Accumulated other comprehensive loss	3,323	6,451
Accumulated deficit	1,301,239	804,216
Total Molycorp stockholders’ equity	637,787	143,896
Noncontrolling interests	0	0
Total stockholders’ equity	637,787	143,896
Total liabilities and stockholders’ equity	($2,155,240)	($2,638,677)

Subsidiary_Guarantor_Financial3

Subsidiary Guarantor Financial Information - Condensed Consolidating Statement of Operations and Comprehensive Income (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Consolidating Statements of Operations and Comprehensive Income
Revenues	$116,242	$123,937	$116,907	$118,526	$123,814	$149,066	$136,112	$145,398	$475,612	$554,390	$527,696
Costs of sales:
Costs excluding depreciation and amortization									-481,417	-553,831	-478,253
Depreciation and amortization									-93,782	-67,727	-30,621
Gross (loss) profit	-44,844	-15,078	-16,571	-23,094	-27,049	-17,778	-18,036	-4,305	-99,587	-67,168	18,822
Operating expenses:
Selling, general and administrative									-74,490	-107,169	-113,437
Corporate development									0	-247	-19,796
Depreciation, amortization and accretion									-29,879	-38,037	-22,187
Research and development									-15,265	-23,172	-27,796
Impairment of goodwill and other long-lived assets									-231,650	-120,898	-301,755
Operating loss									-450,871	-356,691	-466,149
Other (expense) income:
Other (expense) income									-5,092	1,886	-38,798
Foreign exchange (loss) gain, net									-3,146	-376	2,872
Interest expense, net of capitalized interest									-167,375	-67,684	-22,116
Gain on extinguishment of convertible notes, net	19,719								19,719	0	0
Impairment of investments at cost					-9,400				-12,000	-9,411	0
Interest income (expense) from intercompany notes									0	0	0
Equity loss from consolidated subsidiaries									0	0	0
Total other expense									-167,894	-75,585	-58,042
Loss from continuing operations before income taxes and equity earnings	-343,375	-99,484	-89,724	-86,182	-228,592	-76,181	-70,254	-57,249	-618,765	-432,276	-524,191
Income tax benefit									22,594	70,943	54,075
Equity in loss of affiliates									-26,763	-9,169	-3,490
Loss from continuing operations									-622,934	-370,502	-473,606
Loss from discontinued operations, net of tax									0	-6,427	-1,737
Net loss	-347,938	-105,148	-83,850	-85,998	-198,288	-69,799	-70,689	-38,153	-622,934	-376,929	-475,343
Net loss (income) attributable to noncontrolling interests									18,000	2,546	-5,826
Net loss attributable to Molycorp stockholders	-329,795	-105,179	-83,899	-86,061	-194,308	-69,929	-71,175	-38,971	-604,934	-374,383	-481,169
Other comprehensive loss, net of tax:
Foreign currency translation adjustments									4,271	1,623	248
Actuarial loss									-1,143	1,359	-1,200
Comprehensive loss									-619,806	-373,947	-476,295
Comprehensive (loss) income attributable to:
Molycorp stockholders									-601,806	-371,401	-482,121
Noncontrolling interests									-18,000	-2,546	5,826
Parent
Condensed Consolidating Statements of Operations and Comprehensive Income
Revenues									0	0	0
Costs of sales:
Costs excluding depreciation and amortization									0	0	0
Depreciation and amortization									0	0	0
Gross (loss) profit									0	0	0
Operating expenses:
Selling, general and administrative									-425	-190	46
Corporate development										0	-46
Depreciation, amortization and accretion									0	0	0
Research and development									0	0	0
Impairment of goodwill and other long-lived assets									0	0	0
Operating loss									-425	-190	0
Other (expense) income:
Other (expense) income									44	5	-37,589
Foreign exchange (loss) gain, net									-35,914	-9,896	0
Interest expense, net of capitalized interest									-152,144	-64,392	-18,118
Gain on extinguishment of convertible notes, net									19,719
Impairment of investments at cost									0	0
Interest income (expense) from intercompany notes									38,525	36,724	25,157
Equity loss from consolidated subsidiaries									-484,369	-330,604	-456,649
Total other expense									-614,139	-368,163	-487,199
Loss from continuing operations before income taxes and equity earnings									-614,564	-368,353	-487,199
Income tax benefit									9,630	-6,030	6,030
Equity in loss of affiliates									0	0	0
Loss from continuing operations										-374,383	-481,169
Loss from discontinued operations, net of tax										0	0
Net loss									-604,934	-374,383	-481,169
Net loss (income) attributable to noncontrolling interests									0	0	0
Net loss attributable to Molycorp stockholders									-604,934	-374,383	-481,169
Other comprehensive loss, net of tax:
Foreign currency translation adjustments									0	0	0
Actuarial loss									0	0	0
Comprehensive loss									-604,934	-374,383	-481,169
Comprehensive (loss) income attributable to:
Molycorp stockholders									-604,934	-374,383	-481,169
Noncontrolling interests									0	0	0
Guarantor Subsidiaries
Condensed Consolidating Statements of Operations and Comprehensive Income
Revenues									60,795	88,266	139,257
Costs of sales:
Costs excluding depreciation and amortization									-181,599	-200,650	-153,461
Depreciation and amortization									-74,119	-40,220	-12,094
Gross (loss) profit									-194,923	-152,604	-26,298
Operating expenses:
Selling, general and administrative									-36,768	-66,132	-86,493
Corporate development										-247	-19,750
Depreciation, amortization and accretion									-4,946	-6,424	-2,220
Research and development									-526	-5,069	-12,984
Impairment of goodwill and other long-lived assets									-13,831	-14,250	-5,747
Operating loss									-250,994	-244,726	-153,492
Other (expense) income:
Other (expense) income									-1,853	2,169	-328
Foreign exchange (loss) gain, net									5	11	0
Interest expense, net of capitalized interest									-14,897	3,807	-3,496
Gain on extinguishment of convertible notes, net									0
Impairment of investments at cost									-12,000	-9,411
Interest income (expense) from intercompany notes									-2,175	-2,493	3,152
Equity loss from consolidated subsidiaries									-12,655	-7,674	-23,205
Total other expense									-43,575	-13,591	-23,877
Loss from continuing operations before income taxes and equity earnings									-294,569	-258,317	-177,369
Income tax benefit									0	23,130	53,840
Equity in loss of affiliates									-21,350	-6,529	-2,439
Loss from continuing operations										-241,716	-125,968
Loss from discontinued operations, net of tax										0	0
Net loss									-315,919	-241,716	-125,968
Net loss (income) attributable to noncontrolling interests									0	0	0
Net loss attributable to Molycorp stockholders									-315,919	-241,716	-125,968
Other comprehensive loss, net of tax:
Foreign currency translation adjustments									0	0	0
Actuarial loss									0	0	0
Comprehensive loss									-315,919	-241,716	-125,968
Comprehensive (loss) income attributable to:
Molycorp stockholders									-315,919	-241,716	-125,968
Noncontrolling interests									0	0	0
Non-Guarantor Subsidiaries
Condensed Consolidating Statements of Operations and Comprehensive Income
Revenues									452,654	517,202	413,951
Costs of sales:
Costs excluding depreciation and amortization									-337,655	-404,259	-350,304
Depreciation and amortization									-19,663	-27,507	-18,527
Gross (loss) profit									95,336	85,436	45,120
Operating expenses:
Selling, general and administrative									-37,297	-40,847	-26,990
Corporate development										0	0
Depreciation, amortization and accretion									-24,933	-31,613	-19,967
Research and development									-14,739	-18,103	-14,812
Impairment of goodwill and other long-lived assets									-217,819	-106,648	-296,008
Operating loss									-199,452	-111,775	-312,657
Other (expense) income:
Other (expense) income									-3,283	-288	-881
Foreign exchange (loss) gain, net									32,763	9,509	2,872
Interest expense, net of capitalized interest									-334	-7,099	-502
Gain on extinguishment of convertible notes, net									0
Impairment of investments at cost									0	0
Interest income (expense) from intercompany notes									-36,350	-34,231	-28,309
Equity loss from consolidated subsidiaries									0	0	0
Total other expense									-7,204	-32,109	-26,820
Loss from continuing operations before income taxes and equity earnings									-206,656	-143,884	-339,477
Income tax benefit									12,964	53,843	-5,795
Equity in loss of affiliates									-5,413	-2,640	-1,051
Loss from continuing operations										-92,681	-346,323
Loss from discontinued operations, net of tax										-6,427	-1,737
Net loss									-199,105	-99,108	-348,060
Net loss (income) attributable to noncontrolling interests									18,000	2,546	-5,826
Net loss attributable to Molycorp stockholders									-181,105	-96,562	-353,886
Other comprehensive loss, net of tax:
Foreign currency translation adjustments									4,271	1,623	248
Actuarial loss									-1,143	1,359	-1,200
Comprehensive loss									-195,977	-96,126	-349,012
Comprehensive (loss) income attributable to:
Molycorp stockholders									-177,977	-93,580	-354,838
Noncontrolling interests									-18,000	-2,546	5,826
Eliminations
Condensed Consolidating Statements of Operations and Comprehensive Income
Revenues									-37,837	-51,078	-25,512
Costs of sales:
Costs excluding depreciation and amortization									37,837	51,078	25,512
Depreciation and amortization									0	0	0
Gross (loss) profit									0	0	0
Operating expenses:
Selling, general and administrative									0	0	0
Corporate development										0	0
Depreciation, amortization and accretion									0	0	0
Research and development									0	0	0
Impairment of goodwill and other long-lived assets									0	0	0
Operating loss									0	0	0
Other (expense) income:
Other (expense) income									0	0	0
Foreign exchange (loss) gain, net									0	0	0
Interest expense, net of capitalized interest									0	0	0
Gain on extinguishment of convertible notes, net									0
Impairment of investments at cost									0	0
Interest income (expense) from intercompany notes									0	0	0
Equity loss from consolidated subsidiaries									497,024	338,278	479,854
Total other expense									497,024	338,278	479,854
Loss from continuing operations before income taxes and equity earnings									497,024	338,278	479,854
Income tax benefit									0	0	0
Equity in loss of affiliates									0	0	0
Loss from continuing operations										338,278	479,854
Loss from discontinued operations, net of tax										0	0
Net loss									497,024	338,278	479,854
Net loss (income) attributable to noncontrolling interests									0	0	0
Net loss attributable to Molycorp stockholders									497,024	338,278	479,854
Other comprehensive loss, net of tax:
Foreign currency translation adjustments									0	0	0
Actuarial loss									0	0	0
Comprehensive loss									497,024	338,278	479,854
Comprehensive (loss) income attributable to:
Molycorp stockholders									497,024	338,278	479,854
Noncontrolling interests									$0	$0	$0

Subsidiary_Guarantor_Financial4

Subsidiary Guarantor Financial Information - Condensed Consolidating Statements of Cash Flows (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Consolidating Statements of Cash Flows
Net cash (used in) provided by operating activities	($222,204)	($154,351)	($89,635)
Cash flows from investing activities:
Intercompany advances made	0	0	0
Repayments from non-guarantor	0	0	0
Loans to guarantors	0	0
Investment in joint ventures	-703	-3,423	-33,044
Dividends received from equity investment	2,014	0	0
Capital expenditures	-86,158	-379,312	-791,469
Recovery from insurance claims	12,900	0	0
Other investing activities	984	5,477	762
Loans to Parent		0	0
Notes receivable to non-guarantor	0	0	0
Cash paid in connection with acquisitions, net of cash acquired	0	0	-591,011
Loans to subsidiaries			0
Repayments from subsidiaries			0
Investment in subsidiaries			0
Acquisition of exploration rights	0	0	-8,167
Net cash used in investing activities	-70,963	-377,258	-1,422,929
Cash flows from financing activities:
Repayments of debt	-7,825	-26,823	-228,708
Debt issuance costs	-15,260	0	0
Issuance of 10% Senior Secured Notes	250,000		635,373
Partial repayment of convertible notes	-27,495	0	0
Payments of preferred dividends	-2,846	-11,385	-11,385
Dividends paid to noncontrolling interests	-4,222	-4,546	-5,977
Borrowing from non-guarantor	0	0
Borrowings from parent	0	0	0
Borrowings from guarantor	0		0
Repayments to parent	0	0	0
Intercompany advances owed	0	0	0
Repayments of borrowings to guarantor			0
Other financing activities	0	-1,297	-1,554
Issuance of shares to Molymet	0	0	390,093
Capital contributions from parent company			0
Proceeds from debt	0	0	14,699
Net proceeds from sale of common stock	0	495,717	132,130
Proceeds from Convertible Debt		165,600	395,712
Borrowings from guarantor		0
Repayments to guarantor		0
Net cash provided by financing activities	192,352	617,266	1,320,383
Effect of exchange rate changes on cash	-1,817	870	1,116
Net change in cash and cash equivalents	-102,632	86,527	-191,065
Cash and cash equivalents at beginning of the period	314,317	227,790	418,855
Cash and cash equivalents at end of period	211,685	314,317	227,790
Parent
Condensed Consolidating Statements of Cash Flows
Net cash (used in) provided by operating activities	-65,618	-39,075	-13,207
Cash flows from investing activities:
Intercompany advances made	-111,753	-391,560	-1,009,014
Repayments from non-guarantor	39,662	38,000	0
Loans to guarantors	0	0
Investment in joint ventures	0	0	0
Dividends received from equity investment	0
Capital expenditures	0	0	0
Recovery from insurance claims	0
Other investing activities	0	0	0
Loans to Parent		0	0
Notes receivable to non-guarantor	-4,000	-117,512	0
Cash paid in connection with acquisitions, net of cash acquired			0
Loans to subsidiaries			-697,213
Repayments from subsidiaries			101,974
Investment in subsidiaries			-350,000
Acquisition of exploration rights			0
Net cash used in investing activities	-76,091	-471,072	-1,954,253
Cash flows from financing activities:
Repayments of debt	0	0	0
Debt issuance costs	-4,190
Issuance of 10% Senior Secured Notes	50,167		635,373
Partial repayment of convertible notes	-27,495
Payments of preferred dividends	-2,846	-11,385	-11,385
Dividends paid to noncontrolling interests	0	0	0
Borrowing from non-guarantor	0	12,800
Borrowings from parent	0	0	0
Borrowings from guarantor	0		37,589
Repayments to parent	0	0	0
Intercompany advances owed	55,578	0	0
Repayments of borrowings to guarantor			0
Other financing activities		0	-2,938
Issuance of shares to Molymet			390,093
Capital contributions from parent company			0
Proceeds from debt			0
Net proceeds from sale of common stock		495,717	132,130
Proceeds from Convertible Debt		165,600	395,712
Borrowings from guarantor		0
Repayments to guarantor		0
Net cash provided by financing activities	71,214	662,732	1,576,574
Effect of exchange rate changes on cash	0	0	0
Net change in cash and cash equivalents	-70,495	152,585	-390,886
Cash and cash equivalents at beginning of the period	169,145	16,560	407,446
Cash and cash equivalents at end of period	98,650	169,145	16,560
Guarantor Subsidiaries
Condensed Consolidating Statements of Cash Flows
Net cash (used in) provided by operating activities	-178,939	-133,612	-112,386
Cash flows from investing activities:
Intercompany advances made	-2,123	0	0
Repayments from non-guarantor	0	117,776	110,000
Loans to guarantors		0
Investment in joint ventures	0	-3,423	-27,680
Dividends received from equity investment	0
Capital expenditures	-78,557	-361,782	-766,951
Recovery from insurance claims	12,900
Other investing activities	90	4,902	-3,999
Loans to Parent		0	-37,589
Notes receivable to non-guarantor	-5,000	-1,300	-227,512
Cash paid in connection with acquisitions, net of cash acquired			0
Loans to subsidiaries			0
Repayments from subsidiaries			0
Investment in subsidiaries			0
Acquisition of exploration rights			0
Net cash used in investing activities	-72,690	-243,827	-953,731
Cash flows from financing activities:
Repayments of debt	0	0	-870
Debt issuance costs	-7,750
Issuance of 10% Senior Secured Notes	139,833		0
Partial repayment of convertible notes	0
Payments of preferred dividends	0	0	0
Dividends paid to noncontrolling interests	0	0	0
Borrowing from non-guarantor	6,655	40,000
Borrowings from parent	0	0	227,512
Borrowings from guarantor	0		0
Repayments to parent	0	0	-34,327
Intercompany advances owed	111,753	327,183	881,179
Repayments of borrowings to guarantor			0
Other financing activities		-1,297	-115
Issuance of shares to Molymet			0
Capital contributions from parent company			0
Proceeds from debt			0
Net proceeds from sale of common stock		0	0
Proceeds from Convertible Debt		0	0
Borrowings from guarantor		0
Repayments to guarantor		0
Net cash provided by financing activities	250,491	365,886	1,073,379
Effect of exchange rate changes on cash	0	0	0
Net change in cash and cash equivalents	-1,138	-11,553	7,262
Cash and cash equivalents at beginning of the period	6,467	18,020	10,758
Cash and cash equivalents at end of period	5,329	6,467	18,020
Non-Guarantor Subsidiaries
Condensed Consolidating Statements of Cash Flows
Net cash (used in) provided by operating activities	22,353	18,336	35,958
Cash flows from investing activities:
Intercompany advances made	-55,578	0	0
Repayments from non-guarantor	0	0	0
Loans to guarantors	-6,655	-40,000
Investment in joint ventures	-703	0	-5,364
Dividends received from equity investment	2,014
Capital expenditures	-7,601	-17,530	-24,518
Recovery from insurance claims	0
Other investing activities	894	575	4,761
Loans to Parent		-12,800	0
Notes receivable to non-guarantor	0	0	0
Cash paid in connection with acquisitions, net of cash acquired			-591,011
Loans to subsidiaries			0
Repayments from subsidiaries			0
Investment in subsidiaries			0
Acquisition of exploration rights			-8,167
Net cash used in investing activities	-67,629	-69,755	-624,299
Cash flows from financing activities:
Repayments of debt	-7,825	-26,823	-227,838
Debt issuance costs	-3,320
Issuance of 10% Senior Secured Notes	60,000		0
Partial repayment of convertible notes	0
Payments of preferred dividends	0	0	0
Dividends paid to noncontrolling interests	-4,222	-4,546	-5,977
Borrowing from non-guarantor	0	0
Borrowings from parent	4,000	117,512	469,701
Borrowings from guarantor	5,000		227,512
Repayments to parent	-39,662	-38,000	-67,647
Intercompany advances owed	2,123	64,377	127,835
Repayments of borrowings to guarantor			-110,000
Other financing activities		0	1,499
Issuance of shares to Molymet			0
Capital contributions from parent company			350,000
Proceeds from debt			14,699
Net proceeds from sale of common stock		0	0
Proceeds from Convertible Debt		0	0
Borrowings from guarantor		1,300
Repayments to guarantor		-117,776
Net cash provided by financing activities	16,094	-3,956	779,784
Effect of exchange rate changes on cash	-1,817	870	1,116
Net change in cash and cash equivalents	-30,999	-54,505	192,559
Cash and cash equivalents at beginning of the period	138,705	193,210	651
Cash and cash equivalents at end of period	107,706	138,705	193,210
Eliminations
Condensed Consolidating Statements of Cash Flows
Net cash (used in) provided by operating activities	0	0	0
Cash flows from investing activities:
Intercompany advances made	169,454	391,560	1,009,014
Repayments from non-guarantor	-39,662	-155,776	-110,000
Loans to guarantors	6,655	40,000
Investment in joint ventures	0	0	0
Dividends received from equity investment	0
Capital expenditures	0	0	0
Recovery from insurance claims	0
Other investing activities	0	0	0
Loans to Parent		12,800	37,589
Notes receivable to non-guarantor	9,000	118,812	227,512
Cash paid in connection with acquisitions, net of cash acquired			0
Loans to subsidiaries			697,213
Repayments from subsidiaries			-101,974
Investment in subsidiaries			350,000
Acquisition of exploration rights			0
Net cash used in investing activities	145,447	407,396	2,109,354
Cash flows from financing activities:
Repayments of debt	0	0	0
Debt issuance costs	0
Issuance of 10% Senior Secured Notes	0		0
Partial repayment of convertible notes	0
Payments of preferred dividends	0	0	0
Dividends paid to noncontrolling interests	0	0	0
Borrowing from non-guarantor	-6,655	-52,800
Borrowings from parent	-4,000	-117,512	-697,213
Borrowings from guarantor	-5,000		-265,101
Repayments to parent	39,662	38,000	101,974
Intercompany advances owed	-169,454	-391,560	-1,009,014
Repayments of borrowings to guarantor			110,000
Other financing activities		0	0
Issuance of shares to Molymet			0
Capital contributions from parent company			-350,000
Proceeds from debt			0
Net proceeds from sale of common stock		0	0
Proceeds from Convertible Debt		0	0
Borrowings from guarantor		-1,300
Repayments to guarantor		117,776
Net cash provided by financing activities	-145,447	-407,396	-2,109,354
Effect of exchange rate changes on cash	0	0	0
Net change in cash and cash equivalents	0	0	0
Cash and cash equivalents at beginning of the period	0	0	0
Cash and cash equivalents at end of period	$0	$0	$0

Subsidiary_Guarantor_Financial5

Subsidiary Guarantor Financial Information - Classification Errors with Changes Presented (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	error
Number of Classification Errors Affecting the Condensed Consolidating Balance Sheets	2
Number of Classification Errors Affecting the Condensed Consolidating Statements of Cash Flows	1
Condensed Consolidating Balance Sheets
Investments in consolidated subsidiaries	$0	$0
Intercompany accounts receivable	0	0
Additional paid-in capital	2,245,478	2,194,405
Intercompany accounts payable	0	0
Condensed Consolidating Statements of Cash Flows
Loans to subsidiaries			0
Repayments from subsidiaries			0
Borrowings from parent	0	0	0
Repayments to parent	0	0	0
Parent
Condensed Consolidating Balance Sheets
Investments in consolidated subsidiaries	0	0
Intercompany accounts receivable	2,063,568	2,534,350
Additional paid-in capital	2,245,478	2,194,405
Intercompany accounts payable	0	0
Condensed Consolidating Statements of Cash Flows
Loans to subsidiaries			-697,213
Repayments from subsidiaries			101,974
Borrowings from parent	0	0	0
Repayments to parent	0	0	0
Guarantor Subsidiaries
Condensed Consolidating Balance Sheets
Investments in consolidated subsidiaries	91,672	104,327
Intercompany accounts receivable	0	0
Additional paid-in capital	132,335	132,335
Intercompany accounts payable	2,134,041	1,999,562
Condensed Consolidating Statements of Cash Flows
Loans to subsidiaries			0
Repayments from subsidiaries			0
Borrowings from parent	0	0	227,512
Repayments to parent	0	0	-34,327
Non-Guarantor Subsidiaries
Condensed Consolidating Balance Sheets
Investments in consolidated subsidiaries	0	0
Intercompany accounts receivable	0	0
Additional paid-in capital	534,440	534,436
Intercompany accounts payable	658,986	783,011
Condensed Consolidating Statements of Cash Flows
Loans to subsidiaries			0
Repayments from subsidiaries			0
Borrowings from parent	4,000	117,512	469,701
Repayments to parent	-39,662	-38,000	-67,647
Scenario, Previously Reported | Parent
Condensed Consolidating Balance Sheets
Investments in consolidated subsidiaries		532,767
Intercompany accounts receivable		2,001,583
Condensed Consolidating Statements of Cash Flows
Loans to subsidiaries			-683,063
Repayments from subsidiaries			87,824
Scenario, Previously Reported | Guarantor Subsidiaries
Condensed Consolidating Balance Sheets
Investments in consolidated subsidiaries		121,849
Additional paid-in capital		149,857
Scenario, Previously Reported | Non-Guarantor Subsidiaries
Condensed Consolidating Balance Sheets
Additional paid-in capital		1,315,426
Intercompany accounts payable		2,021
Condensed Consolidating Statements of Cash Flows
Borrowings from parent			455,551
Repayments to parent			-53,497
Restatement Adjustment | Parent
Condensed Consolidating Balance Sheets
Investments in consolidated subsidiaries		-532,767
Intercompany accounts receivable		532,767
Condensed Consolidating Statements of Cash Flows
Loans to subsidiaries			-14,150
Repayments from subsidiaries			14,150
Restatement Adjustment | Guarantor Subsidiaries
Condensed Consolidating Balance Sheets
Investments in consolidated subsidiaries		-17,522
Additional paid-in capital		-17,522
Restatement Adjustment | Non-Guarantor Subsidiaries
Condensed Consolidating Balance Sheets
Additional paid-in capital		-780,990
Intercompany accounts payable		780,990
Condensed Consolidating Statements of Cash Flows
Borrowings from parent			14,150
Repayments to parent			($14,150)

Discontinued_Operations_Detail

Discontinued Operations (Details) (USD $)	12 Months Ended			7 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net loss	$0	($6,427)	($1,737)
Napanee Facility
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues		2,091		1,214
Costs of sales		-3,834		-2,691
Selling, general and administrative expenses		-351		-232
Depreciation		-28		-28
Operating loss		-2,122		-1,737
Impairment loss		-4,305		0
Income tax		0		0
Net loss		($6,427)		($1,737)

Unaudited_Supplementary_Data_D

Unaudited Supplementary Data (Details) (USD $)	3 Months Ended								12 Months Ended			0 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]
Revenues	$116,242,000	$123,937,000	$116,907,000	$118,526,000	$123,814,000	$149,066,000	$136,112,000	$145,398,000	$475,612,000	$554,390,000	$527,696,000
Gross loss	-44,844,000	-15,078,000	-16,571,000	-23,094,000	-27,049,000	-17,778,000	-18,036,000	-4,305,000	-99,587,000	-67,168,000	18,822,000
Loss before income taxes and equity earnings	-343,375,000	-99,484,000	-89,724,000	-86,182,000	-228,592,000	-76,181,000	-70,254,000	-57,249,000	-618,765,000	-432,276,000	-524,191,000
Net loss	-347,938,000	-105,148,000	-83,850,000	-85,998,000	-198,288,000	-69,799,000	-70,689,000	-38,153,000	-622,934,000	-376,929,000	-475,343,000
Net loss attributable to Molycorp stockholders	-329,795,000	-105,179,000	-83,899,000	-86,061,000	-194,308,000	-69,929,000	-71,175,000	-38,971,000	-604,934,000	-374,383,000	-481,169,000
(Loss) income per share of common stock from continuing operations
Basic (in dollars per share)	($1.43)	($0.47)	($0.37)	($0.40)	($0.95)	($0.43)	($0.44)	($0.27)	($2.70)	($2.21)	($4.60)
Diluted (in dollars per share)	($1.43)	($0.47)	($0.37)	($0.40)	($0.95)	($0.43)	($0.44)	($0.27)	($2.70)	($2.21)	($4.60)
Quarterly Financial Data [Line Items]
Interest expense, net of capitalized interest									-167,375,000	-67,684,000	-22,116,000
Impairment of investments					9,400,000				12,000,000	9,411,000	0
Tangible Asset Impairment Charges									14,400,000	16,300,000	5,900,000
Gain on extinguishment of convertible notes, net	19,719,000								19,719,000	0	0
Equity Method Investment, Other than Temporary Impairment									19,700,000
Impairment of goodwill and other intangible assets	125,900,000								125,942,000	10,992,000	289,894,000
Exploration rights
Quarterly Financial Data [Line Items]
Tangible Asset Impairment Charges												16,200,000
Impairment of Intangible Assets (Excluding Goodwill)	16,200,000
Net loss
Quarterly Financial Data [Line Items]
Out-of-Period Adjustments, Interim Periods of Fiscal Year									3,842,000
Boulder Wind Power, Inc.
Quarterly Financial Data [Line Items]
Impairment of investments									12,000,000	8,000,000
Boulder Wind Power, Inc. | Other Nonoperating Income (Expense)
Quarterly Financial Data [Line Items]
Impairment of investments		12,000,000								8,000,000
Restatement Adjustment | Own-share Lending Arrangement
Quarterly Financial Data [Line Items]
Interest expense, net of capitalized interest			-4,933,000
Chemicals and Oxides and Rare Metals | Customer relationships
Quarterly Financial Data [Line Items]
Impairment of Intangible Assets (Excluding Goodwill)	$90,900,000