Segment Reporting (Details 2) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	$ 769,379		$ 769,379		$ 787,986
Revenues
Revenue	182,007	$ 166,263	330,394	$ 319,219
United States [Member]
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	332,007		332,007		336,210
Revenues
Revenue	106,236	99,180	199,890	187,249
Mexico [Member]
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	387,562		387,562		390,694
Revenues
Revenue	48,489	39,443	79,011	79,584
BOLIVIA
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	31,297		31,297		35,201
Revenues
Revenue	25,185	23,366	46,463	44,913
Australia [Member]
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	3,235		3,235		5,952
Revenues
Revenue	504	3,083	2,395	5,028
ARGENTINA
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	10,227		10,227		10,871
Other Foreign Countries [Member]
Long Lived Assets
Long Lived Assets in Entity's Country of Domicile	5,051		5,051		$ 9,058
Revenues
Revenue	$ 1,593	$ 1,191	$ 2,635	$ 2,445