Uranium Spot Market Prices Percentage Increase (Decrease)

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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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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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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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The aggregate amount of write-downs for impairments recognized during the period for long-lived assets held for abandonment, exchange or sale.

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- Definition

Mineral properties, net of adjustments.

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The cash inflow from the sale of formerly productive land held for sale, anything permanently fixed to it, including buildings, structures on it, and so forth.

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IMPAIRMENTS (Details) - USD ($)	12 Months Ended
IMPAIRMENTS (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Line Items]
Uranium spot market prices percentage decrease			20.00%
Impairment of plant and equipment and mineral properties	$ 0
Impairment of assets to be abandoned of	0	$ 0	$ 8,220,000
Mineral properties	83,539,000	92,625,000
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
Reno Creek
Goodwill [Line Items]
Impairment of assets to be abandoned of	$ 3,799,000