Special Charges (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($) aircraft
Property, Plant and Equipment [Line Items]
Special charges, non-operating	$ 0	$ 9,201
Special Charges [Abstract]
Special charges	$ 0	89,168
Airbus A319 [Member]
Special Charges [Abstract]
Purchase price		$ 285,000
Airbus A319 [Member] | Capital Lease Obligations [Member]
Special Charges [Abstract]
Number of aircrafts purchased | aircraft		14
Pilots [Member]
Special Charges [Abstract]
Ratification Incentive		$ 80,700
Adjustments for contractual provisions		8,500
Special charges		$ 89,200