Income and Mining Taxes Tax Attribute Carryforward (Details) $ in Thousands	Dec. 31, 2016 USD ($)
Income Tax Examination [Line Items]
Operating Loss Carryforwards	$ 584,100
Tax Credit Carryforward, Alternative Minimum Tax Operating Losses	184,386
Capital Losses Carryforwards	19,394
Alternative Minimum Tax Credits Carryforwards	3,173
Foreign Tax Credits Carryforwards	24,161
UNITED STATES
Income Tax Examination [Line Items]
Operating Loss Carryforwards	330,469
Tax Credit Carryforward, Alternative Minimum Tax Operating Losses	184,386
Capital Losses Carryforwards	19,315
Alternative Minimum Tax Credits Carryforwards	3,173
Foreign Tax Credits Carryforwards	24,161
ARGENTINA
Income Tax Examination [Line Items]
Operating Loss Carryforwards	11,621
Tax Credit Carryforward, Alternative Minimum Tax Operating Losses	0
Capital Losses Carryforwards	0
Alternative Minimum Tax Credits Carryforwards	0
Foreign Tax Credits Carryforwards	0
BOLIVIA
Income Tax Examination [Line Items]
Operating Loss Carryforwards	63,005
Tax Credit Carryforward, Alternative Minimum Tax Operating Losses	0
Capital Losses Carryforwards	0
Alternative Minimum Tax Credits Carryforwards	0
Foreign Tax Credits Carryforwards	0
CANADA
Income Tax Examination [Line Items]
Operating Loss Carryforwards	2,301
Tax Credit Carryforward, Alternative Minimum Tax Operating Losses	0
Capital Losses Carryforwards	79
Alternative Minimum Tax Credits Carryforwards	0
Foreign Tax Credits Carryforwards	0
Mexico
Income Tax Examination [Line Items]
Operating Loss Carryforwards	91,383
Tax Credit Carryforward, Alternative Minimum Tax Operating Losses	0
Capital Losses Carryforwards	0
Alternative Minimum Tax Credits Carryforwards	0
Foreign Tax Credits Carryforwards	0
NEW ZEALAND
Income Tax Examination [Line Items]
Operating Loss Carryforwards	85,258
Tax Credit Carryforward, Alternative Minimum Tax Operating Losses	0
Capital Losses Carryforwards	0
Alternative Minimum Tax Credits Carryforwards	0
Foreign Tax Credits Carryforwards	0
Other Countries
Income Tax Examination [Line Items]
Operating Loss Carryforwards	63
Tax Credit Carryforward, Alternative Minimum Tax Operating Losses	0
Capital Losses Carryforwards	0
Alternative Minimum Tax Credits Carryforwards	0
Foreign Tax Credits Carryforwards	$ 0