Mineral Property Expenditures - Schedule of Mineral Property Expenditures (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Total expense for the period	$ 1,552	$ 1,138	$ 2,321	$ 1,869
Temrezli Project [Member]
Total expense for the period	24	180	123	421
Turkey Project [Member]
Total expense for the period	24	180	123	421
Kingsville Dome Project [Member]
Total expense for the period	155	176	418	410
Rosita Project [Member]
Total expense for the period	172	92	284	160
Vasquez Project [Member]
Total expense for the period	114	102	283	260
Other Project [Member]
Total expense for the period	1	48	2	70
Texas Project [Member]
Total expense for the period	442	418	987	900
Cebolleta Project [Member]
Total expense for the period	538	537	538	537
Juan Tafoya Project [Member]
Total expense for the period	310	3	316	11
Other Projects New Mexico [Member]
Total expense for the period	2		2
New Mexico Project [Member]
Total expense for the period	850	540	856	548
Columbus Basin Project [Member]
Total expense for the period	72		188
Railroad Valley Project, Nevada [Member]
Total expense for the period	155		158
Other Projects, Nevada [Member]
Total expense for the period	2		3
Nevada Projects [Member]
Total expense for the period	229		349
Sal Rica Project, Utah [Member]
Total expense for the period	7		6
Utah Projects [Member]
Total expense for the period	$ 7		$ 6
Railroad Valley Project, Nevada [Member]
Total expense for the period
Sal Rica Project, Utah [Member]
Total expense for the period