Income Taxes (Details) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Deferred:
Income tax benefit (provision) from continuing operations	$ (21,402)	$ 9,372	$ (34,341)	$ 16,370
Income Taxes (Textuals) [Abstract]
Income tax benefit (Provision)	(21,402)	9,372	(34,341)	16,370
ARGENTINA
Current:
Foreign tax expense (benefit)	(15)	(2,128)	83	(2,141)
AUSTRALIA
Current:
Foreign tax expense (benefit)	(760)	(57)	(659)	(57)
Deferred:
Foreign tax expense (benefit)	60	(292)	(459)	(582)
BOLIVIA
Current:
Foreign tax expense (benefit)	(15,926)	(3,721)	(25,005)	(2,890)
Deferred:
Foreign tax expense (benefit)	3,817	(188)	2,859	(1,611)
MEXICO
Current:
Foreign tax expense (benefit)	(90)	(33)	(140)	(83)
Deferred:
Foreign tax expense (benefit)	(6,286)	(4,007)	(10,062)	10,363
UNITED STATES
Deferred:
Federal tax expense (benefit)	(1,789)	20,422	(2,405)	14,486
United States - Alternative Minimum tax [Member]
Current:
Federal tax expense (benefit)			1,938
United States - Foreign Withholding [Member]
Current:
Federal tax expense (benefit)	$ (413)	$ (624)	$ (491)	$ (1,115)