Annual report pursuant to Section 13 and 15(d)

COMMITMENTS AND CONTINGENCIES (Details)

v3.8.0.1
COMMITMENTS AND CONTINGENCIES (Details)
$ in Thousands
 12 Months Ended
Dec. 31, 2017
USD ($)
helicopter
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Operating Leased Assets [Line Items]      
Unfunded capital commitments $ 117,700    
Unfunded capital commitments due in next twelve months 106,400    
Non-cancellable portion due next twelve months 2,800    
Deposits paid on options not yet exercised 1,300    
Amount eligible for termination 116,200    
Amount inclusive of deposits paid and without further liability 2,600    
Escrow deposits 3,250 $ 3,777  
Aircraft maintenance utilized credits $ 1,700 5,000  
Number of helicopters leased | helicopter 4    
Rental expense $ 5,500 $ 5,700 $ 4,500
Minimum      
Operating Leased Assets [Line Items]      
Lease term range 1 year    
Maximum      
Operating Leased Assets [Line Items]      
Lease term range 10 years    
Aeroleo | Municipal Tax Authorities of Rio de Janeiro and Macae | Foreign Tax Authority      
Operating Leased Assets [Line Items]      
Penalties $ 7,100    
Aeroleo | State of Rio de Janeiro | Foreign Tax Authority      
Operating Leased Assets [Line Items]      
Penalties 400    
Installment payments 200    
Damages dismissed 1,600    
Brazilian Tax Dispute with Respect to Employer Social Security Contributions | Aeroleo | Foreign Tax Authority      
Operating Leased Assets [Line Items]      
Penalties 3,000    
Other litigation matters | Aeroleo | Foreign Tax Authority      
Operating Leased Assets [Line Items]      
Escrow deposits 10,300    
Pending Litigation | Tax Disputes over Tax Credits Applied to Offset Social Tax Liability | Brazil Taxing Authorities      
Operating Leased Assets [Line Items]      
Penalties 300    
Pending Litigation | Former Tax Consultant Claims      
Operating Leased Assets [Line Items]      
Penalties 600    
Pending Litigation | Employment-Related Litigation Matters      
Operating Leased Assets [Line Items]      
Damages sought in excess of accruals, value 100    
Unfavorable Regulatory Action | Pending Litigation | Brazilian Customs Authorities Claims      
Operating Leased Assets [Line Items]      
Penalties $ 1,000