Fair Value Measurements Fair Value Measurements (Details 3) (Portion at Other than Fair Value, Fair Value Disclosure [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Convertible Senior Notes Due March 2028 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Financial Liabilities Not Measured at Fair Value	$ 5,067	$ 48,220
Convertible Senior Notes Due March 2028 [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Financial Liabilities Not Measured at Fair Value	5,067	48,220
Convertible Senior Notes Due March 2028 [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Financial Liabilities Not Measured at Fair Value	0	0
Convertible Senior Notes Due March 2028 [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Financial Liabilities Not Measured at Fair Value	0	0
Senior Notes due 2021 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	307,314
Senior Notes due 2021 [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	307,314
Senior Notes due 2021 [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	0
Senior Notes due 2021 [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	0
Palmarejo gold production royalty [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Financial Liabilities Not Measured at Fair Value	65,212	90,617
Palmarejo gold production royalty [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Financial Liabilities Not Measured at Fair Value	0	0
Palmarejo gold production royalty [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Financial Liabilities Not Measured at Fair Value	0	90,617
Palmarejo gold production royalty [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Financial Liabilities Not Measured at Fair Value	$ 65,212	$ 0