Schedule of Compensation Costs for Share-based Payment Arrangements (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Share-based compensation	$ 445	$ 374	$ 1,112	$ 497
Replacement of options from business combinations and asset acquisitions	0	0	0	3,683
Value of stock options granted	$ 445	$ 374	$ 1,112	$ 4,180

Replacement of options from business combinations and asset acquisitions

No definition available.

Name:	efr_ReplacementOfOptionsFromBusinessCombinationsAndAssetAcquisitions
Namespace Prefix:	efr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration