Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements (Details)

v3.5.0.2
Fair Value Measurements (Details) - USD ($)
$ in Thousands
9 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Mar. 31, 2016
Feb. 01, 2016
Liabilities:        
Asset retirement obligation capitalized $ 6,726 $ 5,736    
Level 1        
Assets:        
Derivative Instruments 0      
Liabilities:        
Derivative Instruments 0      
Level 2        
Assets:        
Derivative Instruments 54,625      
Liabilities:        
Derivative Instruments 52,127      
Level 3        
Assets:        
Derivative Instruments 0      
Liabilities:        
Derivative Instruments 0      
Asset retirement obligation capitalized $ 6,700      
Level 3 | Investment in Grizzly Oil Sands ULC        
Liabilities:        
Equity investment     $ 39,100  
Level 3 | Investment in Strike Force Midstream LLC        
Liabilities:        
Equity investment       $ 22,500