Annual report pursuant to Section 13 and 15(d)

Stock Based Compensation (Details)

v3.5.0.2
Stock Based Compensation (Details)
$ / shares in Units, $ in Thousands
1 Months Ended 12 Months Ended
Oct. 10, 2014
shares
Oct. 31, 2014
trading_day
$ / shares
shares
Oct. 31, 2013
trading_day
$ / shares
Jun. 30, 2016
USD ($)
shares
Jun. 30, 2015
USD ($)
shares
Jan. 16, 2013
shares
Jan. 15, 2013
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Stock repurchased from former executive       189,062      
Number of options       0 223,123    
Fair value of stock options vesting | $       $ 32 $ 132    
Stock options exercised (in shares)       0 61,849    
Number of stock options forfeited/canceled       13,958 427,969    
Number of stock options expired       291,403 12,499    
Common shares from options exercised, net of shares withheld for tax obligations (in shares)         34,112    
Cash received from the exercise of stock options | $       $ 0 $ 115    
2012 Stock Incentive Plan              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of shares authorized           625,000  
Number of shares available for grant, reduction for options and stock appreciation rights           1  
Number of shares available for grant, reduction for equity instruments other than options and stock appreciation rights           2  
Expiration term       10 years      
Market based and performance based shares available for future issuance (in shares)       306,481      
1998 Stock Incentive Plan              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of shares authorized             36,054
Number of stock options expired       229,947      
1998 Stock Incentive Plan | Former Executive              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Stock repurchased from former executive 31,250 189,062          
Number of stock options forfeited/canceled       189,062      
RSUs | 2012 Stock Incentive Plan              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Maximum number of shares allowed to be issued each year           62,500  
Employee Stock Option | 2012 Stock Incentive Plan              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Maximum number of shares allowed to be issued each year           125,000  
Market based or performance based options, not vested (in shares)       332,028      
Employee Stock Option | 1998 Stock Incentive Plan | Former Executive              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Stock repurchased from former executive 189,062            
TBOs              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of options         16,875    
TBOs | 2012 Stock Incentive Plan              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of options         16,875    
PBOs              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of options         156,250    
PBOs | 2012 Stock Incentive Plan              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of options   156,250     156,250    
MBOs              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of options         49,998    
Number of consecutive trading days | trading_day   10          
MBOs | 2012 Stock Incentive Plan              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of options   49,998     49,998    
Vesting Period   3 years          
Per share closing price (usd per share) | $ / shares   $ 40.00 $ 18.80        
Number of consecutive trading days | trading_day   90 10        
Median stock price (usd per share) | $ / shares   $ 40.00 $ 18.80        
Other Options              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of options       0      
Preparing Poplar of Commercially Viable CO2-EOR Development | PBOs              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Performance metrics weighted average   40.00%          
Progressing UK Operations in the Weald Basin | PBOs              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Performance metrics weighted average   20.00%          
Moving Forward with Farnham Dome Project | PBOs              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Performance metrics weighted average   20.00%          
CO2-EOR Pilot Program at Poplar | 2012 Stock Incentive Plan              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Performance metrics weighted average     10.00%        
CO2-EOR Development Project at Poplar | 2012 Stock Incentive Plan              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Performance metrics weighted average     40.00%        
CO2-EOR Development Project at Poplar | PBOs              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Performance metrics weighted average   20.00%          
Sale of Substantially All of the Amadeus Basin Assets | 2012 Stock Incentive Plan              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Performance metrics weighted average     20.00%        
Approval of a Farmout Agreement or Participation in Drilling a Well in the Weald Basin | 2012 Stock Incentive Plan              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Performance metrics weighted average     20.00%        
Approval of a Farmout Agreement in the Bonaparte Basin | 2012 Stock Incentive Plan              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Performance metrics weighted average     10.00%