| 
           Other items not affecting cash flow (Details) (USD $) 
        In Thousands, unless otherwise specified  | 
        12 Months Ended | |
|---|---|---|
| 
           Dec. 31, 2013 
         | 
        
           Dec. 31, 2012 
         | 
      |
| Non-cash financing and investing activities: | ||
| Common shares issued for properties | $ 783us-gaap_StockIssuedDuringPeriodValuePurchaseOfAssets | |
| Mineral property acquired in asset exchange | $ 970urg_MineralPropertyAcquiredInAssetExchange | |
| X | ||||||||||
| 
             
- Definition 
          Amount of mineral property acquired in asset exchange during the period. No definition available. 
  | 
        
| X | ||||||||||
| 
             
- Details 
          
  | 
        
| X | ||||||||||
| 
             
- Definition 
          Value of shares of stock issued during the period as part of a transaction to acquire assets that do not qualify as a business combination. No definition available. 
  |