Commitments and Contingencies - Future Minimum Lease Payments Under Noncancelable Operating Leases (Details) $ in Thousands	Jun. 30, 2016 USD ($)
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
remainder of 2016	$ 118,831
Future Minimum Payments Due, 2017	222,750
Future Minimum Payments Due, 2018	205,015
Future Minimum Payments Due, 2019	179,976
Future Minimum Payments Due, 2020	164,486
Future Minimum Payments Due, 2021 and thereafter	565,603
Total minimum lease payments	1,456,661
Aircraft and Spare Engine Leases [Member]
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
remainder of 2016	101,877
Future Minimum Payments Due, 2017	194,445
Future Minimum Payments Due, 2018	177,054
Future Minimum Payments Due, 2019	155,356
Future Minimum Payments Due, 2020	147,379
Future Minimum Payments Due, 2021 and thereafter	514,483
Total minimum lease payments	1,290,594
Property Facility Leases [Member]
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
remainder of 2016	16,954
Future Minimum Payments Due, 2017	28,305
Future Minimum Payments Due, 2018	27,961
Future Minimum Payments Due, 2019	24,620
Future Minimum Payments Due, 2020	17,107
Future Minimum Payments Due, 2021 and thereafter	51,120
Total minimum lease payments	$ 166,067