Derivative Financial Instruments and Fair Value of Financial Instruments (Details 1) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Fair value of the derivative instruments
Derivative Asset, Fair Value	$ 1,440
Prepaid expenses and other [Member]
Fair value of the derivative instruments
Derivative Asset, Fair Value	2,201	814
Accrued liabilities and other [Member]
Fair value of the derivative instruments
Derivative Asset, Fair Value	2,925	7,196
Other long-term liabilities [Member]
Fair value of the derivative instruments
Derivative Asset, Fair Value	13,915	14,669
Current portion of royalty obligation [Member]
Fair value of the derivative instruments
Derivative Asset, Fair Value	46,005	37,206
Non-current portion of royalty obligation [Member]
Fair value of the derivative instruments
Derivative Asset, Fair Value	124,148	122,194
Silver ounces received from Mandalay [Member]
Fair value of the derivative instruments
Derivative Asset, Fair Value	676	814
Silver ounces received from Mandalay [Member] | Prepaid expenses and other [Member]
Fair value of the derivative instruments
Derivative Asset, Fair Value	676	814
Silver ounces received from Mandalay [Member] | Accrued liabilities and other [Member]
Fair value of the derivative instruments
Derivative Asset, Fair Value
Silver ounces received from Mandalay [Member] | Other long-term liabilities [Member]
Fair value of the derivative instruments
Derivative Asset, Fair Value
Silver ounces received from Mandalay [Member] | Current portion of royalty obligation [Member]
Fair value of the derivative instruments
Derivative Asset, Fair Value
Silver ounces received from Mandalay [Member] | Non-current portion of royalty obligation [Member]
Fair value of the derivative instruments
Derivative Asset, Fair Value
Forward foreign exchange contracts [Member] | Prepaid expenses and other [Member]
Fair value of the derivative instruments
Derivative Liability, Fair Value	286
Forward foreign exchange contracts [Member] | Accrued liabilities and other [Member]
Fair value of the derivative instruments
Derivative Liability, Fair Value	80	3,188
Forward foreign exchange contracts [Member] | Other long-term liabilities [Member]
Fair value of the derivative instruments
Derivative Liability, Fair Value
Forward foreign exchange contracts [Member] | Current portion of royalty obligation [Member]
Fair value of the derivative instruments
Derivative Liability, Fair Value
Forward foreign exchange contracts [Member] | Non-current portion of royalty obligation [Member]
Fair value of the derivative instruments
Derivative Liability, Fair Value
Palmarejo gold production royalty [Member] | Prepaid expenses and other [Member]
Fair value of the derivative instruments
Derivative Liability, Fair Value
Palmarejo gold production royalty [Member] | Accrued liabilities and other [Member]
Fair value of the derivative instruments
Derivative Liability, Fair Value
Palmarejo gold production royalty [Member] | Other long-term liabilities [Member]
Fair value of the derivative instruments
Derivative Liability, Fair Value
Palmarejo gold production royalty [Member] | Current portion of royalty obligation [Member]
Fair value of the derivative instruments
Derivative Liability, Fair Value	46,005	37,206
Palmarejo gold production royalty [Member] | Non-current portion of royalty obligation [Member]
Fair value of the derivative instruments
Derivative Liability, Fair Value	124,148	122,194
Put and call options, net [Member] | Prepaid expenses and other [Member]
Fair value of the derivative instruments
Derivative Liability, Fair Value
Put and call options, net [Member] | Accrued liabilities and other [Member]
Fair value of the derivative instruments
Derivative Liability, Fair Value	2,840	3,183
Put and call options, net [Member] | Other long-term liabilities [Member]
Fair value of the derivative instruments
Derivative Liability, Fair Value	13,915	14,669
Put and call options, net [Member] | Current portion of royalty obligation [Member]
Fair value of the derivative instruments
Derivative Liability, Fair Value
Put and call options, net [Member] | Non-current portion of royalty obligation [Member]
Fair value of the derivative instruments
Derivative Liability, Fair Value
Concentrate sales contracts [Member] | Prepaid expenses and other [Member]
Fair value of the derivative instruments
Derivative Asset, Fair Value	1,239
Concentrate sales contracts [Member] | Accrued liabilities and other [Member]
Fair value of the derivative instruments
Derivative Asset, Fair Value	5	825
Concentrate sales contracts [Member] | Other long-term liabilities [Member]
Fair value of the derivative instruments
Derivative Asset, Fair Value
Concentrate sales contracts [Member] | Current portion of royalty obligation [Member]
Fair value of the derivative instruments
Derivative Asset, Fair Value
Concentrate sales contracts [Member] | Non-current portion of royalty obligation [Member]
Fair value of the derivative instruments
Derivative Asset, Fair Value