Commitments and Contigencies (Details Textual) (USD $)	0 Months Ended	3 Months Ended			3 Months Ended		9 Months Ended		3 Months Ended			0 Months Ended	1 Months Ended	0 Months Ended
	Jan. 21, 2009	Sep. 30, 2014 oz	Sep. 30, 2013	Oct. 14, 2009 m	Sep. 30, 2014 Rochester [Member]	Sep. 30, 2013 Rochester [Member]	Sep. 30, 2013 Rochester [Member]	Jul. 07, 1995 Echo Bay [Member] oz	Sep. 30, 2014 Kensington [Member]	Jul. 07, 1995 Kensington [Member]	Jul. 07, 1995 Coeur Alaska Inc [Member]	Jun. 05, 2012 Hazardous Waste On-Site [Member] Callahan Mining Corporation [Member] defendant	Feb. 28, 2010 Hazardous Waste On-Site [Member] Callahan Mining Corporation [Member]	Oct. 02, 2014 Subsequent Event [Member]
Other Commitments [Line Items]
Litigation Settlement, Expense			$ 32,000,000
Termination payment														2,000,000.0
Production to be sold, percent														50.00%
Sale of production, price per ounce of gold														800
Aggregate deposit to be received														22,000,000.0
Commitment and Contingencies (Textual) [Abstract]
Acquisition of ownership interest								50.00%		100.00%
Volume related to net smelter return royalty of future gold production								1,000,000
Purchase price and construction and development expenses											32,500,000
Minimum royalty range for gold price per ounce									1.00%
Gold price per ounce for minimum royalty range									400
Maximum royalty range for gold price per ounce					5.00%				2.50%
Maximum royalty payable					250,000
Gold price per ounce for maximum royalty range					23.60				475
Royalty expenses					0	0	1,000,000
Litigation Settlement, Amount			10,000,000										3,500,000
Number of defendants												5
Maximum Height for Temporary Restriction on Mining				4,400
NSR royalty percentage			3.40%
NSR royalty maximum amount			$ 39,400,000
Number of labor agreements in South America		1
Percentage of labor force covered by collective bargaining agreements		9.90%
Royalty to be capped in terms of ounces of production		1,000,000
Purchased royalty	50.00%
Royalty agreement minimum obligation for the period		400,000
Royalty Agreement Minimum Obligation for Per Month		4,167
Royalty Agreement Period	8 years