Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References+ Details

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References+ Details

- Definition

Fair value of financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, elected not to be offset against a right to receive collateral under a master netting arrangement.

+ References+ Details

- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References+ Details

- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References+ Details

Note 10 - Derivative Instruments (Details) (USD $)	2 Months Ended	6 Months Ended	12 Months Ended
Note 10 - Derivative Instruments (Details) (USD $)	Mar. 01, 2012	Jun. 30, 2013	Dec. 31, 2012	Dec. 31, 2011
Note 10 - Derivative Instruments (Details) [Line Items]
Derivative Asset, Current			$ 5,600,000
Derivative, Gain on Derivative		7,200,000	10,500,000	7,100,000
Derivative Liability, Noncurrent			2,500,000
Payments for (Proceeds from) Derivative Instrument, Financing Activities	3,100,000
Forecasted Future Concentrate Contracts [Member]
Note 10 - Derivative Instruments (Details) [Line Items]
Derivative Asset, Current		9,800,000	2,300,000
Derivative, Gain on Derivative		28,100,000
Derivative Liability, Current		300,000
Derivative Asset, Noncurrent		14,600,000
Unsettled Concentrate Sales Contracts [Member]
Note 10 - Derivative Instruments (Details) [Line Items]
Derivative Asset, Current		200,000
Derivative, Gain on Derivative		2,800,000	1,300,000
Derivative Liability, Current		200,000
Net From Current Asset Balance [Member]
Note 10 - Derivative Instruments (Details) [Line Items]
Derivative Liability, Fair Value, Amount Not Offset Against Collateral			1,000,000
Net From Non Current Liability Balance [Member]
Note 10 - Derivative Instruments (Details) [Line Items]
Derivative Liability, Fair Value, Amount Not Offset Against Collateral			100,000
Losses Realized On Settled Contracts [Member]
Note 10 - Derivative Instruments (Details) [Line Items]
Derivative, Gain on Derivative			$ 18,400,000