Property, Plant and Equipment (Details Narrative) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) a $ / shares	Dec. 31, 2016 USD ($)	Jun. 20, 2017 a
Property, Plant and Equipment [Line Items]
Area of land | a			9,270
Average long term price of asset | $ / shares	$ 41.34
Asset impairment charges	$ 11,436	$ 1,673
Drop of Acreage [Member]
Property, Plant and Equipment [Line Items]
Net area on mineral leases | a	1,542
General Directorate [Member]
Property, Plant and Equipment [Line Items]
Percentage of royalty, ranging	1.00%
Railroad Valley Project [Member] | June [Member]
Property, Plant and Equipment [Line Items]
Area of land | a	9,270
Columbus Basin Project [Member] | July and September 2016 [Member]
Property, Plant and Equipment [Line Items]
Area of land | a	14,200
Sal Rica Project [Member]
Property, Plant and Equipment [Line Items]
Area of land | a	9,900
Area of unpatented mining claims | a	3,360
Percentage of NSR royalty	2.00%
Temrezli Project [Member]
Property, Plant and Equipment [Line Items]
Granted licenses cover area | a	13,490
Temrezli Project [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Percentage of royalty, ranging	2.00%
Temrezli Project [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Percentage of royalty, ranging	16.00%
Kingsville Dome Project [Member]
Property, Plant and Equipment [Line Items]
Gross area on mineral leases | a	2,434
Net area on mineral leases | a	2,227
Asset impairment charges	$ 100	200
Kingsville Dome Project [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Percentage of royalties on lease of sales	6.25%
Annual per acre royalty payable | $ / shares	$ 10
Kingsville Dome Project [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Percentage of royalties on lease of sales	9.375%
Annual per acre royalty payable | $ / shares	$ 30
Rosita Project [Member]
Property, Plant and Equipment [Line Items]
Gross area on mineral leases | a	2,759
Net area on mineral leases | a	2,759
Rosita South Property [Member]
Property, Plant and Equipment [Line Items]
Gross area on mineral leases | a	1,795
Net area on mineral leases | a	1,479
Rosita [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Percentage of royalties on lease of sales	6.25%
Annual per acre royalty payable | $ / shares	$ 10
Rosita [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Percentage of royalties on lease of sales	18.25%
Annual per acre royalty payable | $ / shares	$ 30
Mineral sales price per pound | $ / shares	$ 80.00
Vasquez Project [Member]
Property, Plant and Equipment [Line Items]
Gross area on mineral leases | a	872
Net area on mineral leases | a	872
Vasquez Project [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Percentage of royalties on lease of sales	6.25%
Mineral sales price per pound | $ / shares	$ 25.00
Vasquez Project [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Percentage of royalties on lease of sales	10.25%
Mineral sales price per pound | $ / shares	$ 40.00
Butler Ranch Exploration Project [Member]
Property, Plant and Equipment [Line Items]
Net area on mineral leases | a	990
Butler Ranch Exploration Project [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Annual per acre royalty payable | $ / shares	$ 10
Lease term	8 years
Butler Ranch Exploration Project [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Percentage of royalties on lease of sales	10.00%
Annual per acre royalty payable | $ / shares	$ 25
Lease term	10 years
Cebolleta Property [Member]
Property, Plant and Equipment [Line Items]
Area of land | a	6,717
Lease term	10 years
Initial payments per lease agreement	$ 5,000
Amount used in the calculation of recoverable reserve payment per unit	1.00
Royalty payable	$ 1,500
Annual advance royalties previously paid	500
Reduction in advanced royalty payment	350
Payment on commencement of production	$ 4,000
Fixed royalty percentage	5.75%
Cebolleta Property [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Percentage of royalties on lease of sales	4.50%
Cebolleta Property [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Percentage of royalties on lease of sales	8.00%
Feasibility study term	6 years
Annual advance royalties previously paid	$ 5,000
Amount of deduction to recoverable reserve payment	$ 6,500
Juan Tafoya Property [Member]
Property, Plant and Equipment [Line Items]
Area of land | a	115
Lease term	10 years
Initial payments per lease agreement	$ 250
Reduction in advanced royalty payment	$ 174
Fixed royalty percentage	4.00%
Area of land in mineral fee interest acquired | a	4,097
Annual base rent per acre | $ / shares	$ 75
Reduction of market value per pound | $ / shares	$ 25
Juan Tafoya Property [Member] | First Five Year [Member]
Property, Plant and Equipment [Line Items]
Annual rental payments	$ 225
Juan Tafoya Property [Member] | Second Five Year [Member]
Property, Plant and Equipment [Line Items]
Annual rental payments	$ 337
Juan Tafoya Property [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Percentage of royalties on lease of sales	4.65%
Juan Tafoya Property [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Percentage of royalties on lease of sales	6.50%
Cebolleta/Juan Tafoya Property [Member]
Property, Plant and Equipment [Line Items]
Asset impairment charges	$ 11,296
Carrying value impairment	7,800
Butler Ranch Project [Member]
Property, Plant and Equipment [Line Items]
Asset impairment charges		579
Sejita Dome Project [Member]
Property, Plant and Equipment [Line Items]
Asset impairment charges		534
Nell Project [Member]
Property, Plant and Equipment [Line Items]
Asset impairment charges		209
Jack Pump Project [Member]
Property, Plant and Equipment [Line Items]
Asset impairment charges		191
Mineral Property [Member]
Property, Plant and Equipment [Line Items]
Mineral property expenses	$ 4,600	$ 3,200