Income and Mining Taxes (Details Textual) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Income Tax Contingency [Line Items]
Foreign Exchange Income Tax Expense (Benefit)	$ 3,000		$ 8,600
Income Tax Expense (Benefit)	(2,098)	$ (768)	8,948	$ 1,338
Unrecognized Tax Benefits	17,400		17,400		$ 19,600
Income Tax Examination, Penalties and Interest Expense			8,400		$ 8,700
Minimum [Member]
Income Tax Contingency [Line Items]
Decrease in Unrecognized Tax Benefits is Reasonably Possible	1,500		1,500
Maximum [Member]
Income Tax Contingency [Line Items]
Decrease in Unrecognized Tax Benefits is Reasonably Possible	$ 2,500		$ 2,500