Fair Value Measurements (Details 1) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Assets:
Total assets	$ 11,905
Liabilities:
Total liabilities	15,876	$ 15,058
Royalty obligation embedded derivative [Member]
Liabilities:
Derivative fair value of derivative liability		4,957
Rochester Royalty Obligation [Member]
Liabilities:
Derivative fair value of derivative liability		9,593
Other Derivative Instrument [Member]
Assets:
Fair value of derivative asset	655
Liabilities:
Derivative fair value of derivative liability		508
Equity Securities [Member]
Assets:
Equity securities	11,250	2,766
Fair Value, Inputs, Level 1 [Member]
Assets:
Total assets	11,243
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]
Assets:
Fair value of derivative asset	0
Liabilities:
Derivative fair value of derivative liability		0
Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member]
Assets:
Equity securities	11,243	2,756
Fair Value, Inputs, Level 2 [Member]
Assets:
Total assets	655
Liabilities:
Total liabilities	0	508
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]
Assets:
Fair value of derivative asset	655
Liabilities:
Derivative fair value of derivative liability		508
Fair Value, Inputs, Level 2 [Member] | Equity Securities [Member]
Assets:
Equity securities	0	0
Fair Value, Inputs, Level 3 [Member]
Assets:
Total assets	7
Liabilities:
Total liabilities	15,876	14,550
Fair Value, Inputs, Level 3 [Member] | Royalty obligation embedded derivative [Member]
Liabilities:
Derivative fair value of derivative liability		4,957
Fair Value, Inputs, Level 3 [Member] | Rochester Royalty Obligation [Member]
Liabilities:
Derivative fair value of derivative liability		9,593
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] | Equity Securities [Member]
Assets:
Equity securities	7	$ 10
Palmarejo Royalty Obligation [Member] | Royalty obligation embedded derivative [Member]
Liabilities:
Derivative fair value of derivative liability	3,317
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	3,317
Rochester Royalty Obligation [Member] | Royalty Obligation [Member]
Liabilities:
Derivative fair value of derivative liability	12,559
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	$ 12,559