Mineral Property Expenditures - Schedule of Mineral Property Expenditures (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Total expense for the period	$ 782	$ 769
Temrezli Project, Turkey [Member]
Total expense for the period	(79)	(98)
Total Turkey Projects [Member]
Total expense for the period	(79)	(98)
Kingsville Dome Project, Texas [Member]
Total expense for the period	(251)	(262)
Rosita Project, Texas [Member]
Total expense for the period	(197)	(112)
Vasquez Project, Texas [Member]
Total expense for the period	(235)	(169)
Other Projects, Texas [Member]
Total expense for the period	(6)	(1)
Total Texas Projects [Member]
Total expense for the period	(689)	(544)
Juan Tafoya Project, New Mexico [Member]
Total expense for the period	(6)	(6)
Total New Mexico Projects [Member]
Total expense for the period	(6)	(6)
Columbus Basin Project, Nevada [Member]
Total expense for the period	(2)	(117)
Railroad Valley, Neveda [Member]
Total expense for the period	(4)	(4)
Total Nevada Projects [Member]
Total expense for the period	(6)	(121)
Sal Rica Project, Utah [Member]
Total expense for the period	(2)
Total Utah Projects [Member]
Total expense for the period	$ (2)