Segment Reporting (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Long Lived Assets
Long Lived Assets, Total	$ 2,637,648		$ 2,675,811
Revenues
Total Revenue	171,797	204,564
UNITED STATES
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	505,593		514,663
Revenues
Total Revenue	78,748	29,135
AUSTRALIA
Long Lived Assets
Long Lived Assets in Individual Foreign Countries	28,584		29,408
Revenues
Total Revenue	2,983	6,713
CHILE
Long Lived Assets
Long Lived Assets in Individual Foreign Countries	21		24
ARGENTINA
Long Lived Assets
Long Lived Assets in Individual Foreign Countries	95,053		95,134
Revenues
Total Revenue	(501)	3,618
BOLIVIA
Long Lived Assets
Long Lived Assets in Individual Foreign Countries	237,157		240,905
Revenues
Total Revenue	33,141	41,376
MEXICO
Long Lived Assets
Long Lived Assets in Individual Foreign Countries	1,771,240		1,795,677
Revenues
Total Revenue	$ 57,426	$ 123,722