Significant Customers (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Standard [Member] | Palmarejo San Bartolome [Member]
Customers total revenue
Customers total revenue	$ 9.9	$ 50.5	$ 24.5	$ 50.5
Valcambi [Member] | Palmarejo San Bartolome [Member]
Customers total revenue
Customers total revenue	148.3	90.3	256.3	142.9
China Gold [Member] | Palmarejo San Bartolome [Member]
Customers total revenue
Customers total revenue			16.0	69.3
International Commodities [Member] | Palmarejo San Bartolome [Member]
Customers total revenue
Customers total revenue			$ 23.8	$ 46.2
Sales Revenue, Segment [Member]
Revenue, Major Customer [Line Items]
Concentration Risk, Percentage	10.00%		10.00%