Quarterly report pursuant to Section 13 or 15(d)

Asset Retirement and Reclamation Obligations (Details)

v2.4.1.9
Asset Retirement and Reclamation Obligations (Details) (USD $)
3 Months Ended 12 Months Ended
Mar. 31, 2015
Dec. 31, 2014
Asset retirement obligations    
Estimated Future Cash Undiscounted Amount $ 24,800,000urg_EstimatedFutureCashUndiscountedAmount  
Asset Retirement Obligation Rollforward    
Beginning of year 23,445,000us-gaap_AssetRetirementObligation 17,279,000us-gaap_AssetRetirementObligation
Change in estimated liability   5,669,000us-gaap_AssetRetirementObligationRevisionOfEstimate
Accretion expense 126,000us-gaap_AssetRetirementObligationAccretionExpense 497,000us-gaap_AssetRetirementObligationAccretionExpense
End of period $ 23,571,000us-gaap_AssetRetirementObligation $ 23,445,000us-gaap_AssetRetirementObligation