Property, Plant and Equipment - Schedule of Mineral Property Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Total expense for the period	$ 3,538	$ 4,584
Temrezli Project, Turkey [Member]
Total expense for the period	117	261
Total Turkey Projects [Member]
Total expense for the period	117	261
Kingsville Dome Project, Texas [Member]
Total expense for the period	800	810
Rosita Project, Texas [Member]
Total expense for the period	738	590
Vasquez Project, Texas [Member]
Total expense for the period	631	572
Other Projects, Texas [Member]
Total expense for the period	20	71
Total Texas Projects [Member]
Total expense for the period	2,189	2,043
Cebolleta Project, New Mexico [Member]
Total expense for the period	389	538
Juan Tafoya Project, New Mexico [Member]
Total expense for the period	223	542
Total New Mexico Projects [Member]
Total expense for the period	612	1,080
Columbus Basin Project, Nevada [Member]
Total expense for the period	249	866
Railroad Valley Project, Nevada [Member]
Total expense for the period	90	241
Total Nevada Projects [Member]
Total expense for the period	339	1,107
Sal Rica Project, Utah [Member]
Total expense for the period	141	93
Total Utah Projects [Member]
Total expense for the period	141	93
Coosa Project, Alabama [Member]
Total expense for the period	140
Total Alabama Projects [Member]
Total expense for the period	$ 140