Fair Value Measurements (Details 1) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Jan. 29, 2013
Assets:
Assets, Fair Value Disclosure	10,002	14,656
Liabilities:
Financial and Nonfinancial Liabilities, Fair Value Disclosure	39,126	63,559
Royalty obligation embedded derivative [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability		40,338
Rochester Royalty Obligation [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability		21,630
Other Derivative Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	805	1,591
Gold Put Purchase and Call Sold Options Net [Member]
Assets:
Fair value of derivative asset	3,882
Liabilities:
Derivative Liability, Fair Value, Gross Liability	1,039
Short-term Deposit [Member]
Assets:
Short-term Deposits	138	14,521
Equity securities [Member]
Assets:
Restricted certificates of deposits	5,982	135
Fair Value, Inputs, Level 1 [Member]
Assets:
Assets, Fair Value Disclosure	4,741	14,521
Liabilities:
Financial and Nonfinancial Liabilities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 1 [Member] | Royalty obligation embedded derivative [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	0	0
Fair Value, Inputs, Level 1 [Member] | Royalty Obligation [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	0
Fair Value, Inputs, Level 1 [Member] | Rochester Royalty Obligation [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability		0
Fair Value, Inputs, Level 1 [Member] | Other Derivative Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	0	0
Fair Value, Inputs, Level 1 [Member] | Gold Put Purchase and Call Sold Options Net [Member]
Assets:
Fair value of derivative asset	0
Liabilities:
Derivative Liability, Fair Value, Gross Liability	0
Fair Value, Inputs, Level 1 [Member] | Short-term Deposit [Member]
Assets:
Short-term Deposits	138	14,521
Fair Value, Inputs, Level 1 [Member] | Equity securities [Member]
Assets:
Restricted certificates of deposits	4,603	0
Fair Value, Inputs, Level 2 [Member]
Assets:
Assets, Fair Value Disclosure	3,882	135
Liabilities:
Financial and Nonfinancial Liabilities, Fair Value Disclosure	1,844	1,591
Fair Value, Inputs, Level 2 [Member] | Royalty obligation embedded derivative [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	0	0
Fair Value, Inputs, Level 2 [Member] | Royalty Obligation [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	0
Fair Value, Inputs, Level 2 [Member] | Rochester Royalty Obligation [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability		0
Fair Value, Inputs, Level 2 [Member] | Other Derivative Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	805	1,591
Fair Value, Inputs, Level 2 [Member] | Gold Put Purchase and Call Sold Options Net [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	1,039
Fair Value, Inputs, Level 2 [Member] | Short-term Deposit [Member]
Assets:
Short-term Deposits	0	0
Fair Value, Inputs, Level 2 [Member] | Equity securities [Member]
Assets:
Restricted certificates of deposits	0	135
Fair Value, Inputs, Level 3 [Member]
Assets:
Assets, Fair Value Disclosure	1,379	0
Liabilities:
Financial and Nonfinancial Liabilities, Fair Value Disclosure	37,282	61,968
Fair Value, Inputs, Level 3 [Member] | Royalty obligation embedded derivative [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	21,912	40,338
Fair Value, Inputs, Level 3 [Member] | Royalty Obligation [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	15,370
Fair Value, Inputs, Level 3 [Member] | Rochester Royalty Obligation [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability		21,630
Fair Value, Inputs, Level 3 [Member] | Other Derivative Instrument [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	0	0
Fair Value, Inputs, Level 3 [Member] | Gold Put Purchase and Call Sold Options Net [Member]
Assets:
Fair value of derivative asset	0
Liabilities:
Derivative Liability, Fair Value, Gross Liability	0
Fair Value, Inputs, Level 3 [Member] | Short-term Deposit [Member]
Assets:
Short-term Deposits	0	0
Fair Value, Inputs, Level 3 [Member] | Equity securities [Member]
Assets:
Restricted certificates of deposits	1,379	0
Prepaid Expenses and Other Current Assets [Member]
Assets:
Fair value of derivative asset	3,925	184
Prepaid Expenses and Other Current Assets [Member] | Gold Put Purchase and Call Sold Options Net [Member]
Assets:
Fair value of derivative asset	3,882	135
Palmarejo royalty obligation [Member] | Royalty obligation embedded derivative [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	21,912
Rochester Royalty Obligation [Member] | Royalty Obligation [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	15,370
Reported Value Measurement [Member] | Palmarejo gold production royalty [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	34,047	51,193
Portion at Other than Fair Value Measurement [Member] | Palmarejo gold production royalty [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	38,290	65,212
Portion at Other than Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member] | Palmarejo gold production royalty [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	0	0
Portion at Other than Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Palmarejo gold production royalty [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	0	0
Portion at Other than Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Palmarejo gold production royalty [Member]
Liabilities:
Derivative Liability, Fair Value, Gross Liability	38,290	65,212
Convertible Senior Notes Due March 2028 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.25%	3.25%
Convertible Senior Notes Due March 2028 [Member] | Reported Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Line of Credit	14,785
Convertible Debt, Fair Value Disclosures	5,334	5,334
Convertible Senior Notes Due March 2028 [Member] | Portion at Other than Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Line of Credit	14,785
Convertible Debt, Fair Value Disclosures	4,979	5,067
Convertible Senior Notes Due March 2028 [Member] | Portion at Other than Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Line of Credit	0
Convertible Debt, Fair Value Disclosures	0	5,067
Convertible Senior Notes Due March 2028 [Member] | Portion at Other than Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Line of Credit	14,785
Convertible Debt, Fair Value Disclosures	4,979	0
Convertible Senior Notes Due March 2028 [Member] | Portion at Other than Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Line of Credit	0
Convertible Debt, Fair Value Disclosures	0	0
Senior Notes due Two Thousand Twenty One [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.875%	7.875%	7.875%