PROPERTY, PLANT AND EQUIPMENT - Net Book Value of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Net property, plant and equipment	$ 20,414	$ 20,337
Texas
Net property, plant and equipment	3,534	3,439
Alabama
Net property, plant and equipment	8,972	8,972
New Mexico
Net property, plant and equipment	7,806	7,806
Corporate
Net property, plant and equipment	102	120
Uranium plant
Net property, plant and equipment	3,112	3,112
Uranium plant | Texas
Net property, plant and equipment	3,112	3,112
Mineral rights and properties
Net property, plant and equipment	16,778	16,778
Mineral rights and properties | Alabama
Net property, plant and equipment	8,972	8,972
Mineral rights and properties | New Mexico
Net property, plant and equipment	7,806	7,806
Other property, plant and equipment
Net property, plant and equipment	524	447
Other property, plant and equipment | Texas
Net property, plant and equipment	422	327
Other property, plant and equipment | Corporate
Net property, plant and equipment	$ 102	$ 120