Income and Mining Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income tax provision from continuing operations
Income before income and mining taxes	$ (16,937)	$ (40,500)	$ (50,157)	$ (82,380)
Income and mining tax benefit (expense)	260	(2,621)	192	2,068
United States - Alternative minimum tax [Member]
Income Tax Examination [Line Items]
Income (Loss) from Continuing Operations before Income Taxes, Domestic	(9,764)	(31,370)	(30,471)	(60,214)
Income tax provision from continuing operations
Federal tax expense (benefit)	319	(146)	2,204	(292)
Argentina [Member]
Income tax provision from continuing operations
Income (Loss) from Continuing Operations before Income Taxes, Foreign	(656)	(688)	(1,352)	(2,892)
Foreign tax expense (benefit)	(1)	(349)	(2)	4,083
Mexico [Member]
Income tax provision from continuing operations
Income (Loss) from Continuing Operations before Income Taxes, Foreign	(5,582)	(12,710)	(15,255)	(28,716)
Foreign tax expense (benefit)	548	107	(716)	3,828
BOLIVIA
Income tax provision from continuing operations
Income (Loss) from Continuing Operations before Income Taxes, Foreign	(1,219)	3,957	(3,598)	8,649
Foreign tax expense (benefit)	196	(2,205)	(1,211)	(4,969)
Other Countries [Member]
Income tax provision from continuing operations
Income (Loss) from Continuing Operations before Income Taxes, Foreign	284	311	519	793
Foreign tax expense (benefit)	$ (802)	$ (28)	$ (83)	$ (582)