Income and Mining Taxes (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	$ (40,800)
Deferred Other Tax Expense (Benefit)	$ 15,000
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Other Information	19.6	17.9	16.1
Income Tax Contingency [Line Items]
Income Tax Expense (Benefit)	$ (54,239)	$ (26,263)	$ (428,254)
Income Tax Examination, Penalties and Interest Expense	8,700	$ 9,200	$ 6,900
Minimum [Member]
Income Tax Contingency [Line Items]
Decrease in Unrecognized Tax Benefits is Reasonably Possible	1,500
Maximum [Member]
Income Tax Contingency [Line Items]
Decrease in Unrecognized Tax Benefits is Reasonably Possible	$ 2,500