Derivative Instruments (Outstanding Forward and Future Contracts) (Details) - Total derivatives not designated as hedging instruments - Future $ in Millions	Dec. 31, 2016 USD ($) oz T lb
Silver (ounces)
Derivative [Line Items]
Amount \| oz	607,684
Notional Value	$ 9.7
Gold (ounces)
Derivative [Line Items]
Amount \| oz	400
Notional Value	$ 0.5
Copper (pounds)
Derivative [Line Items]
Amount \| lb	275,000
Notional Value	$ 0.6
Tin (metric tons)
Derivative [Line Items]
Amount \| T	40
Notional Value	$ 0.8

- Definition

Aggregate notional amount of derivative expressed in nonmonetary units. For example, the number of barrels specified in a fuel oil forward purchase contract.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

+ Details

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- Definition

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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