XML 56 R39.htm IDEA: XBRL DOCUMENT
v3.19.1

PLANT AND EQUIPMENT AND MINERAL PROPERTIES - Schedule of Summary of Mineral Properties (Details) - USD ($) $ in Thousands | Mar. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Property, Plant and Equipment [Line Items] |  |
Mineral properties | $ 83,539 | $ 83,539
Uranerz ISR properties |  |
Property, Plant and Equipment [Line Items] |  |
Mineral properties | 25,974 | 25,974
Sheep Mountain |  |
Property, Plant and Equipment [Line Items] |  |
Mineral properties | 34,183 | 34,183
Roca Honda |  |
Property, Plant and Equipment [Line Items] |  |
Mineral properties | 22,095 | 22,095
Other |  |
Property, Plant and Equipment [Line Items] |  |
Mineral properties | $ 1,287 | $ 1,287

X
- Definition Mineral properties, net of adjustments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 360 -Section 25 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=96866604&loc=d3e64895-109465 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229 + Details
Name: | us-gaap_MineralPropertiesNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition 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. + References No definition available. + Details
Name: | us-gaap_PropertyPlantAndEquipmentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | efr_MineralPropertiesAxis=efr_UranerzISRPropertiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | efr_MineralPropertiesAxis=efr_SheepMountainMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | efr_MineralPropertiesAxis=efr_RocaHondaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | efr_MineralPropertiesAxis=efr_OtherMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |