Quarterly report pursuant to Section 13 or 15(d)

Variable Interest Entities (Details)

v3.19.2
Variable Interest Entities (Details) - helicopter
6 Months Ended
Jun. 30, 2019
Dec. 31, 2018
Apr. 06, 2018
Jun. 30, 2019
Variable Interest Entity [Line Items]        
Percentage of ownership 100.00% 100.00%    
Dire Wolf Energy Services LLC | Cobra Aviation Services LLC        
Variable Interest Entity [Line Items]        
Interest transferred     100.00%  
Cobra Aviation Services LLC        
Variable Interest Entity [Line Items]        
Number of helicopters     3  
ARS        
Variable Interest Entity [Line Items]        
Percentage of ownership     100.00%  
Wexford        
Variable Interest Entity [Line Items]        
Percentage of ownership 48.90% 49.00% 49.00% 49.00%