Quarterly report pursuant to Section 13 or 15(d)

VARIABLE INTEREST ENTITIES - Narrative (Details)

v3.7.0.1
VARIABLE INTEREST ENTITIES - Narrative (Details) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Dec. 31, 2016
Dec. 31, 2011
Variable Interest Entity [Line Items]            
Operating revenues $ 57,878 $ 63,351 $ 112,405 $ 125,933    
Aeroleo            
Variable Interest Entity [Line Items]            
Economic interest percent           50.00%
Voting interest percent           20.00%
Aeroleo | Variable Interest Entity, Primary Beneficiary            
Variable Interest Entity [Line Items]            
Assets 11,000   11,000   $ 12,900  
Liabilities 8,800   8,800   $ 9,200  
Operating revenues 7,000 6,500 17,200 14,000    
Net gain (loss) from consolidation $ (2,600) $ (1,400) $ (1,600) $ (2,100)