PROPERTY, PLANT AND EQUIPMENT - Net Book Value of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Total Property, Plant and Equipment	$ 116,033	$ 90,078
Mineral rights and properties
Property, Plant and Equipment [Line Items]
Total Property, Plant and Equipment	8,972	8,972
Other property, plant and equipment
Property, Plant and Equipment [Line Items]
Total Property, Plant and Equipment	5,733	5,769
Construction in progress
Property, Plant and Equipment [Line Items]
Total Property, Plant and Equipment	101,328	75,337
Alabama
Property, Plant and Equipment [Line Items]
Total Property, Plant and Equipment	116,011	90,054
Alabama | Mineral rights and properties
Property, Plant and Equipment [Line Items]
Total Property, Plant and Equipment	8,972	8,972
Alabama | Other property, plant and equipment
Property, Plant and Equipment [Line Items]
Total Property, Plant and Equipment	5,711	5,745
Alabama | Construction in progress
Property, Plant and Equipment [Line Items]
Total Property, Plant and Equipment	101,328	75,337
Corporate
Property, Plant and Equipment [Line Items]
Total Property, Plant and Equipment	22	24
Corporate | Other property, plant and equipment
Property, Plant and Equipment [Line Items]
Total Property, Plant and Equipment	$ 22	$ 24