text: 1) The Oklahoma US state tax jurisdiction computes income taxes on a direct accounting basis. A significant 
  portion of the 2014 impairment related to this jurisdiction resulting in a deferred tax benefit of $3,044 
  creating deferred tax assets, of which $2,064 were unrecognized. 
  
  2) The change in apportioned state tax rates in US controlled entities is a result of the Company disposing of 
  its property in Colorado (income tax rate of 4.63%) (2013: North Dakota with income tax rate of 4.53%) 
  through a tax deferred sale and reinvesting the property in Texas (margin tax rate of 1%). As the Texas 
  margin tax computation is similar in nature to an income tax computation, it is treated as an income tax for 
  financial reporting purposes. 
  
  3) This income tax benefit results from the election to consolidate certain Australian subsidiaries for income 
  tax purposes effective 1 January 2014, making previously unrecognized deferred tax assets of one of these 
  Australian subsidiaries available for utilization against future income of the consolidated Australian entities. 
  These deferred tax assets were previously unrecognized due to the lack of evidence of future taxable 
  income for these Australian subsidiaries on a stand-alone basis. 