DISCONTINUED OPERATIONS - Carrying amounts of major classes of assets - (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]
Restricted Cash	$ 3,000		$ 3,000
Current Assets Held for Sale	9,306	$ 151
Disposal Group, Including Discontinued Operation, Assets, Noncurrent [Abstract]
Assets Held for Sale, non-current		14,356
Disposal Group, Including Discontinued Operation, Liabilities, Current [Abstract]
Current Liabilities Held for Sale	7,758	1,701
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent [Abstract]
Liabilities Held for Sale, non-current		5,914
Uranium And Lithium Operations | Discontinued Operations, Held-for-sale or Disposed of by Sale [Member]
Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]
Restricted Cash	3,000
Prepaid and other current assets	89	151
Net property, plant and equipment	6,207
Operating lease right-of-use assets	10
Current Assets Held for Sale	9,306	151
Disposal Group, Including Discontinued Operation, Assets, Noncurrent [Abstract]
Net property, plant and equipment		11,342
Operating lease right-of-use assets		14
Restricted cash		3,000
Assets Held for Sale, non-current		14,356
Total Assets Held for Sale	9,306	14,507
Disposal Group, Including Discontinued Operation, Liabilities, Current [Abstract]
Accounts payable	140	25
Accrued liabilities	808	776
Asset retirement obligations - current	5,969	894
Operating lease liability - current	10	6
Notes payable - current	331
Other current liabilities	500
Current Liabilities Held for Sale	7,758	1,701
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent [Abstract]
Asset retirement obligations, net of current		5,406
Operating lease liability, net of current		8
Other long-term liabilities		500
Liabilities Held for Sale, non-current		5,914
Total Liabilities Held for Sale	$ 7,758	$ 7,615