Quarterly report pursuant to Section 13 or 15(d)

Customer Concentration (Details)

v3.8.0.1
Customer Concentration (Details) - USD ($)
$ in Thousands
6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Dec. 31, 2016
Dec. 31, 2015
Concentration Risk [Line Items]        
Cash and cash equivalents $ 66,554 $ 196,709 $ 50,686 $ 223,552
Sales Revenue Segment | Customer Concentration Risk        
Concentration Risk [Line Items]        
Southwest Airlines, concentration risk, percent 19.00% 24.00%    
Sales Revenue Segment | Customer Concentration Risk | Connectivity        
Concentration Risk [Line Items]        
Southwest Airlines, concentration risk, percent 37.00% 83.00%    
Accounts Receivable | Customer Concentration Risk        
Concentration Risk [Line Items]        
Southwest Airlines, concentration risk, percent 12.00% 12.00%    
Foreign Subsidiaries        
Concentration Risk [Line Items]        
Cash and cash equivalents $ 34,400