Mineral Property Expenditures - Schedule of Mineral Property Expenditures (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Total expense for the period	$ 955	$ 1,316	$ 2,706	$ 3,637
Temrezli Project, Turkey [Member]
Total expense for the period	11	63	107	186
Total Turkey Projects [Member]
Total expense for the period	11	63	107	186
Kingsville Dome Project, Texas [Member]
Total expense for the period	223	197	646	616
Rosita Project, Texas [Member]
Total expense for the period	259	188	614	472
Vasquez Project, Texas [Member]
Total expense for the period	42	117	374	399
Other Projects, Texas [Member]
Total expense for the period	25	26	26	30
Total Texas Projects [Member]
Total expense for the period	549	528	1,660	1,517
Cebolleta Project, New Mexico [Member]
Total expense for the period			389	538
Juan Tafoya Project, New Mexico [Member]
Total expense for the period	39	38	48	356
Total New Mexico Projects [Member]
Total expense for the period	39	38	437	894
Columbus Basin Project, Nevada [Member]
Total expense for the period	126	489	248	678
Railroad Valley Project, Nevada [Member]
Total expense for the period	79	80	95	238
Total Nevada Projects [Member]
Total expense for the period	205	569	343	916
Sal Rica Project, Utah [Member]
Total expense for the period	112	118	112	124
Total Utah Projects [Member]
Total expense for the period	112	118	112	124
Coosa Project, Alabama [Member]
Total expense for the period	39		47
Total Alabama Projects [Member]
Total expense for the period	$ 39		$ 47