Fair Value Measurements (Details 1) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013	Jan. 29, 2013
Assets:
Total assets	$ 62,941	$ 14,656
Liabilities:
Total liabilities	67,907	63,559
Royalty obligation embedded derivative [Member]
Liabilities:
Derivative fair value of derivative liability		40,338
Rochester Royalty Obligation [Member]
Liabilities:
Derivative fair value of derivative liability		21,630
Other Derivative Instrument [Member]
Assets:
Fair value of derivative asset	240
Liabilities:
Derivative fair value of derivative liability		1,591
Gold Put Purchase and Call Sold Options Net [Member]
Assets:
Fair value of derivative asset	1,298
Liabilities:
Derivative fair value of derivative liability	291
Short-term Deposit [Member]
Assets:
Short-term Deposits	47,642	14,521
Marketable securities [Member]
Assets:
Restricted certificates of deposits	13,761	135
Fair Value, Inputs, Level 1 [Member]
Assets:
Total assets	61,403	14,521
Liabilities:
Total liabilities	0	0
Fair Value, Inputs, Level 1 [Member] | Royalty obligation embedded derivative [Member]
Liabilities:
Derivative fair value of derivative liability	0	0
Fair Value, Inputs, Level 1 [Member] | Royalty Obligation [Member]
Liabilities:
Derivative fair value of derivative liability	0
Fair Value, Inputs, Level 1 [Member] | Rochester Royalty Obligation [Member]
Liabilities:
Derivative fair value of derivative liability		0
Fair Value, Inputs, Level 1 [Member] | Other Derivative Instrument [Member]
Assets:
Fair value of derivative asset	0
Liabilities:
Derivative fair value of derivative liability		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 fair value of derivative liability	0
Fair Value, Inputs, Level 1 [Member] | Short-term Deposit [Member]
Assets:
Short-term Deposits	47,642	14,521
Fair Value, Inputs, Level 1 [Member] | Marketable securities [Member]
Assets:
Restricted certificates of deposits	13,761	0
Fair Value, Inputs, Level 2 [Member]
Assets:
Total assets	1,538	135
Liabilities:
Total liabilities	291	1,591
Fair Value, Inputs, Level 2 [Member] | Royalty obligation embedded derivative [Member]
Liabilities:
Derivative fair value of derivative liability	0	0
Fair Value, Inputs, Level 2 [Member] | Royalty Obligation [Member]
Liabilities:
Derivative fair value of derivative liability	0
Fair Value, Inputs, Level 2 [Member] | Rochester Royalty Obligation [Member]
Liabilities:
Derivative fair value of derivative liability		0
Fair Value, Inputs, Level 2 [Member] | Other Derivative Instrument [Member]
Assets:
Fair value of derivative asset	240
Liabilities:
Derivative fair value of derivative liability		1,591
Fair Value, Inputs, Level 2 [Member] | Gold Put Purchase and Call Sold Options Net [Member]
Liabilities:
Derivative fair value of derivative liability	291
Fair Value, Inputs, Level 2 [Member] | Short-term Deposit [Member]
Assets:
Short-term Deposits	0	0
Fair Value, Inputs, Level 2 [Member] | Marketable securities [Member]
Assets:
Restricted certificates of deposits	0	135
Fair Value, Inputs, Level 3 [Member]
Assets:
Total assets	0	0
Liabilities:
Total liabilities	67,616	61,968
Fair Value, Inputs, Level 3 [Member] | Royalty obligation embedded derivative [Member]
Liabilities:
Derivative fair value of derivative liability	43,960	40,338
Fair Value, Inputs, Level 3 [Member] | Royalty Obligation [Member]
Liabilities:
Derivative fair value of derivative liability	23,656
Fair Value, Inputs, Level 3 [Member] | Rochester Royalty Obligation [Member]
Liabilities:
Derivative fair value of derivative liability		21,630
Fair Value, Inputs, Level 3 [Member] | Other Derivative Instrument [Member]
Assets:
Fair value of derivative asset	0
Liabilities:
Derivative fair value of derivative liability		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 fair value of derivative liability	0
Fair Value, Inputs, Level 3 [Member] | Short-term Deposit [Member]
Assets:
Short-term Deposits	0	0
Fair Value, Inputs, Level 3 [Member] | Marketable securities [Member]
Assets:
Restricted certificates of deposits	0	0
Prepaid Expenses and Other Current Assets [Member]
Assets:
Fair value of derivative asset	1,539	184
Prepaid Expenses and Other Current Assets [Member] | Palmarejo gold production royalty [Member]
Assets:
Fair value of derivative asset
Prepaid Expenses and Other Current Assets [Member] | Gold Put Purchase and Call Sold Options Net [Member]
Assets:
Fair value of derivative asset	1,298	135
Palmarejo Royalty Obligation [Member] | Royalty obligation embedded derivative [Member]
Liabilities:
Derivative fair value of derivative liability	43,960
Rochester Royalty Obligation [Member] | Royalty Obligation [Member]
Liabilities:
Derivative fair value of derivative liability	$ 23,656
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%
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%