Segment Reporting (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	$ 827,734		$ 729,103
Revenues
Revenue	152,956	159,633
United States [Member]
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	376,966		275,594
Revenues
Revenue	88,069	60,215
Australia [Member]
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	20,104		21,362
Revenues
Revenue	1,945	2,889
Argentina [Member]
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	10,944		10,970
BOLIVIA
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	104,122		107,960
Revenues
Revenue	21,548	27,554
Mexico [Member]
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	300,756		298,101
Revenues
Revenue	40,141	68,511
Other Foreign Countries [Member]
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	14,842		15,116
Revenues
Revenue	$ 1,253	$ 464