Condensed Consolidated Statements of Stockholders' Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Class A Common Stock	Total Molycorp Stockholders' Equity	Common Stock	Series A Mandatory Convertible Preferred Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Retained Earnings	Non controlling interests	Molymet	Molymet Total Molycorp Stockholders' Equity	Molymet Common Stock	Molymet Additional Paid-In Capital	Molycorp Canada Total Molycorp Stockholders' Equity	Molycorp Canada Common Stock	Molycorp Canada Additional Paid-In Capital	Molycorp Canada Non controlling interests	Molycorp Silmet	Molycorp Silmet Total Molycorp Stockholders' Equity	Molycorp Silmet Common Stock	Molycorp Silmet Additional Paid-In Capital	Molycorp Silmet Non controlling interests
Balance at the beginning of period at Dec. 31, 2009	$ 74,615	$ 45	$ 74,615	$ 0		$ 117,231		$ (42,661)	$ 0
Balance at the beginning of the period (in shares) at Dec. 31, 2009		44,998,185		0
Increase (Decrease) in Stockholders' Equity
Issuance of shares	15,000	6	15,000			14,994
Issuance of shares (in shares)		5,767,670
Exercise of employee options	300	0	300			300
Exercise of employee options (in shares)		126,405
Issuance of shares for conversion of convertible securities, value		(51)		51
Issuance of shares for conversion of convertible securities, shares		(50,892,260)		50,892,260
Sale of shares of common stock at $14.00 per share in initial public offering on August 3, 2010, net of underwriting fees and other offering costs of $29.2 million	378,633		378,633	29		378,604
Sale of shares of common stock at $14.00 per share in initial public offering on August 3, 2010, net of underwriting fees and other offering costs of $29.2 million (in shares)				29,128,700
Conversion of Class B common stock to common stock in conjunction with the initial public offering on August 3, 2010	28,663		28,663	2		28,661
Conversion of Class B common stock to common stock in conjunction with the initial public offering on August 3, 2010 (in shares)				2,232,740
Stock-based compensation	76		76	0		76
Stock-based compensation (in shares)				37,500
Net (loss) income	(50,774)		(50,774)					(50,774)
Balance at the end of the period at Dec. 31, 2010	446,513		446,513	82	0	539,866	0	(93,435)	0
Balance at the end of the period (in shares) at Dec. 31, 2010				82,291,200	0
Increase (Decrease) in Stockholders' Equity
Sale of Series A mandatory convertible preferred stock at $100.00 per share, net of underwriting fees and other offering costs	199,642		199,642		2	199,640
Sale of Series A mandatory convertible preferred stock, net of underwriting fees and other offering costs (in shares)					2,070,000
Stock-based compensation	4,671		4,671	0		4,671
Stock-based compensation (in shares)				11,424
Issuance of shares for interest in subsidiary																		81,475	72,655	2	72,653	8,820
Issuance of shares for interest in subsidiary, (in shares)																				1,593,419
Component of convertible debt (Note 14)	36,227		36,227			36,227
Deferred taxes on component of convertible debt	(14,138)		(14,138)			(14,138)
Net (loss) income	118,334		117,526					117,526	808
Preferred dividends	(9,013)		(9,013)					(9,013)
Other comprehensive loss	(8,481)		(8,058)				(8,058)		(423)
Acquisition of noncontrolling interests	(10,000)		(795)			(372)	(423)		(9,205)
Balance at the end of the period at Dec. 31, 2011	845,230		845,230	84	2	838,547	(8,481)	15,078	0
Balance at the end of the period (in shares) at Dec. 31, 2011				83,896,043	2,070,000
Increase (Decrease) in Stockholders' Equity
Issuance of shares	132,130		132,130	14		132,116				390,093	390,093	12	390,081
Issuance of shares (in shares)				13,800,000								12,500,000
Issuance of shares for conversion of convertible securities, value	1,421		1,421			1,421
Issuance of shares for conversion of convertible securities, shares				99,723
Stock-based compensation	3,434		3,434	0		3,434
Stock-based compensation (in shares)				3,740
Issuance of shares for interest in subsidiary	334,887													284,144	14	284,130	50,743
Issuance of shares for interest in subsidiary, (in shares)															13,885,622
Issuance of shares for acquisition of exploration rights (Note 8)	8,000		8,000	1		7,999
Issuance of shares for investment in mining properties (Note 16) (in shares)				788,410
Component of convertible debt (Note 14)	71,801		71,801			71,801
Deferred taxes on component of convertible debt	(27,106)		(27,106)			(27,106)
Issuance of Borrowed Shares (Note 16)	25		25	14		11
Issuance of Borrowed Shares (Note 16) (in shares)				13,800,000
Net (loss) income	(475,343)		(481,169)					(481,169)	5,826
Preferred dividends	(11,385)		(11,385)			(11,385)
Distribution to noncontrolling interests	(5,977)					0			(5,977)
Other comprehensive loss	(952)		(952)				(952)
Acquisition of noncontrolling interests	(15,000)		380			380			(15,380)
Balance at the end of the period at Dec. 31, 2012	$ 1,251,258		$ 1,216,046	$ 139	$ 2	$ 1,691,429	$ (9,433)	$ (466,091)	$ 35,212
Balance at the end of the period (in shares) at Dec. 31, 2012				138,773,538	2,070,000