Segment Reporting (Details 2) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	$ 797,172		$ 787,986
Revenues
Revenue	148,387	$ 152,956
United States [Member]
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	347,021		336,210
Revenues
Revenue	93,654	88,069
Mexico [Member]
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	397,406		390,694
Revenues
Revenue	30,522	40,141
BOLIVIA
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	33,519		35,201
Revenues
Revenue	21,278	21,548
Australia [Member]
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	3,317		5,952
Revenues
Revenue	1,891	1,945
Argentina [Member]
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	10,843		10,871
Other Foreign Countries [Member]
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	5,066		$ 9,058
Revenues
Revenue	$ 1,042	$ 1,253