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IMPAIRMENTS (Details) - USD ($)	3 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill [Line Items]
Uranium spot market prices percentage decrease			20.00%
Impairment of plant and equipment and mineral properties		$ 0	$ 8,224,000	$ 80,071,000
Impairment of assets to be abandoned of		0	8,224,000	80,071,000
Mineral properties		$ 92,625,000	91,031,000
Conventional Uranium Recovery
Goodwill [Line Items]
Impairment of assets to be abandoned of	$ 75,050,000			5,020,000
Reclassification to assets held-for-sale				$ 7,530,000
Cooper King, Marquez Ranch, and Nose Rock | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Goodwill [Line Items]
Mineral properties			1,300,000
Proceeds from the sale of mineral interests			1,360,000
Uranerz Energy Corporation
Goodwill [Line Items]
Goodwill acquired during the period			$ 47,730,000

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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale).

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Mineral properties, net of adjustments.

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