Fair Value Measurements (Details 1) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Assets:
Total assets	$ 5,466	$ 9,864
Liabilities:
Total liabilities	29,822	39,126
Royalty obligation embedded derivative [Member]
Liabilities:
Derivative fair value of derivative liability		21,912
Rochester Royalty Obligation [Member]
Liabilities:
Derivative fair value of derivative liability		15,370
Other Derivative Instrument [Member]
Liabilities:
Derivative fair value of derivative liability	513	805
Gold Put Purchase and Call Sold Options Net [Member]
Assets:
Fair value of derivative asset	1,250
Liabilities:
Derivative fair value of derivative liability	123	1,039
Short-term Deposit [Member]
Assets:
Short-term deposits		5,982
Marketable securities [Member]
Assets:
Restricted certificates of deposits	4,216	3,882
Fair Value, Inputs, Level 1 [Member]
Assets:
Total assets	4,127	4,603
Liabilities:
Total liabilities	0	0
Fair Value, Inputs, Level 1 [Member] | Royalty obligation embedded derivative [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]
Liabilities:
Derivative fair value of derivative 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 fair value of derivative liability	0	0
Fair Value, Inputs, Level 1 [Member] | Short-term Deposit [Member]
Assets:
Short-term deposits		4,603
Fair Value, Inputs, Level 1 [Member] | Marketable securities [Member]
Assets:
Restricted certificates of deposits	4,127	0
Fair Value, Inputs, Level 2 [Member]
Assets:
Total assets	1,250	3,882
Liabilities:
Total liabilities	636	1,844
Fair Value, Inputs, Level 2 [Member] | Royalty obligation embedded derivative [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]
Liabilities:
Derivative fair value of derivative liability	513	805
Fair Value, Inputs, Level 2 [Member] | Gold Put Purchase and Call Sold Options Net [Member]
Assets:
Fair value of derivative asset	1,250
Liabilities:
Derivative fair value of derivative liability		1,039
Fair Value, Inputs, Level 2 [Member] | Short-term Deposit [Member]
Assets:
Short-term deposits		0
Fair Value, Inputs, Level 2 [Member] | Marketable securities [Member]
Assets:
Restricted certificates of deposits	0	3,882
Fair Value, Inputs, Level 3 [Member]
Assets:
Total assets	89	1,379
Liabilities:
Total liabilities	29,186	37,282
Fair Value, Inputs, Level 3 [Member] | Royalty obligation embedded derivative [Member]
Liabilities:
Derivative fair value of derivative liability		21,912
Fair Value, Inputs, Level 3 [Member] | Rochester Royalty Obligation [Member]
Liabilities:
Derivative fair value of derivative liability		15,370
Fair Value, Inputs, Level 3 [Member] | Other Derivative Instrument [Member]
Liabilities:
Derivative fair value of derivative 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 fair value of derivative liability	0	0
Fair Value, Inputs, Level 3 [Member] | Short-term Deposit [Member]
Assets:
Short-term deposits		1,379
Fair Value, Inputs, Level 3 [Member] | Marketable securities [Member]
Assets:
Restricted certificates of deposits	89	$ 0
Palmarejo Royalty Obligation [Member] | Royalty obligation embedded derivative [Member]
Liabilities:
Derivative fair value of derivative liability	15,281
Palmarejo Royalty Obligation [Member] | Fair Value, Inputs, Level 1 [Member] | Royalty obligation embedded derivative [Member]
Liabilities:
Derivative fair value of derivative liability	0
Palmarejo Royalty Obligation [Member] | Fair Value, Inputs, Level 2 [Member] | Royalty obligation embedded derivative [Member]
Liabilities:
Derivative fair value of derivative liability	0
Palmarejo Royalty Obligation [Member] | Fair Value, Inputs, Level 3 [Member] | Royalty obligation embedded derivative [Member]
Liabilities:
Derivative fair value of derivative liability	15,281
Rochester Royalty Obligation [Member] | Royalty Obligation [Member]
Liabilities:
Derivative fair value of derivative liability	13,905
Rochester Royalty Obligation [Member] | Fair Value, Inputs, Level 1 [Member] | Royalty Obligation [Member]
Liabilities:
Derivative fair value of derivative liability	0
Rochester Royalty Obligation [Member] | Fair Value, Inputs, Level 2 [Member] | Royalty Obligation [Member]
Liabilities:
Derivative fair value of derivative liability	0
Rochester Royalty Obligation [Member] | Fair Value, Inputs, Level 3 [Member] | Royalty Obligation [Member]
Liabilities:
Derivative fair value of derivative liability	$ 13,905