Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Components of loss from continuing operations before income taxes
United States	$ (38,781)	$ (37,710)	$ 25,650
Foreign	246,618	(54,955)	(101,723)
Loss from continuing operations before income taxes	207,836	(92,665)	(76,073)
Deferred:
Income tax benefit	(114,337)	9,481	33,071
United States - Alternative minimum tax [Member]
Current:
Federal tax expense (benefit)	2,015	(482)	(2,249)
United States - Foreign withholding tax [Member]
Current:
Federal tax expense (benefit)	(842)	(1,009)	(1,509)
Argentina [Member]
Current:
Foreign tax expense (benefit)	(1,219)	(7,094)	(6,284)
Australia [Member]
Current:
Foreign tax expense (benefit)	(1,755)	(251)	592
Deferred:
Foreign tax expense (benefit)	(661)	(541)	200
Mexico [Member]
Current:
Foreign tax expense (benefit)	(1,084)	(316)	(124)
Deferred:
Foreign tax expense (benefit)	(28,022)	24,371	37,681
Bolivia [Member]
Current:
Foreign tax expense (benefit)	(59,660)	(20,268)	(2,673)
Deferred:
Foreign tax expense (benefit)	(207)	(1,388)	(6,221)
Canada [Member]
Current:
Foreign tax expense (benefit)	0		(53)
United States [Member]
Deferred:
Federal tax expense (benefit)	$ (22,902)	$ 16,459	$ 13,711