Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Deferred:
Income tax provision from continuing operations	$ (68,612)	$ (114,337)	$ 9,481
Components of loss from continuing operations before income taxes
United States	(5,638)	(38,781)	(37,710)
Foreign	122,927	246,617	(54,955)
Income before income taxes	117,289	207,836	(92,665)
United States - Alternative minimum tax [Member]
Current:
Federal tax expense (benefit)	(257)	2,015	(482)
United States - Foreign withholding tax [Member]
Current:
Federal tax expense (benefit)	(736)	(842)	(1,009)
Argentina [Member]
Current:
Foreign tax expense (benefit)	976	(1,219)	(7,094)
Australia [Member]
Current:
Foreign tax expense (benefit)	(1,760)	(1,755)	(251)
Deferred:
Foreign tax expense (benefit)	(223)	(661)	(541)
Mexico [Member]
Current:
Foreign tax expense (benefit)	(7,814)	(1,084)	(316)
Deferred:
Foreign tax expense (benefit)	(10,579)	(28,022)	24,371
Bolivia [Member]
Current:
Foreign tax expense (benefit)	(43,546)	(59,660)	(20,268)
Deferred:
Foreign tax expense (benefit)	(1,087)	(207)	(1,388)
United States [Member]
Deferred:
Federal tax expense (benefit)	$ (3,586)	$ (22,902)	$ 16,459