Acquisitions (Details) (USD $)	0 Months Ended				12 Months Ended			0 Months Ended
	Dec. 17, 2014	Jul. 02, 2014	May 27, 2014	Apr. 16, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jul. 02, 2014	Dec. 13, 2013
Business Acquisition [Line Items]
Shares Issued for Acquisition				11,572,918
Share Price for Acquisition				$ 14,980
Business Acquisition, Effective Date of Acquisition	Dec. 16, 2014	Jul. 02, 2014	May 27, 2014	Apr. 16, 2013
Sale of Stock, Percentage of Ownership after Transaction	20.16%
Payments to Acquire Businesses, Gross	$ 8,500,000
Payments to Acquire Royalty Interests in Mining Properties			2,200,000		48,395,000	57,034,000	74,734,000
La Preciosa Net Smelter Royalty			1.25%
Acquisition Costs, Period Cost						1,500,000
Payments for Royalties			1,800,000		4,000,000
Business Acquisition, Date of Acquisition Agreement			Sep. 02, 2014
Business Combination, Consideration Transferred				295,841,000
Business Combination, Contingent Consideration, Liability, Noncurrent									8,605,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities				116,955,000					26,047,000
Business Combination, Consideration Transferred, Cost of Acquired Entity				412,796,000					34,652,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets				412,796,000					34,652,000
Warrants Issued for Acquisition				1,588,768
Warrant Price for Acquisition				$ 3,640
Paramount Gold & Silver [Member]
Business Acquisition [Line Items]
Business Combination, Step Acquisition, Equity Interest in Acquiree, Description	0.049
La Preciosa Net Smelter Royalty	0.70%
Business Combination, Consideration Transferred	5,300,000
La Preciosa [Member]
Business Acquisition [Line Items]
La Preciosa Net Smelter Royalty								3.00%
Business Combination, Consideration Transferred								$ 12,000,000