Commitments and Contingencies - Future Minimum Lease Payments Under Noncancelable Operating Leases (Details) $ in Thousands	Sep. 30, 2016 USD ($)
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
remainder of 2016	$ 61,810
Future Minimum Payments Due, 2017	229,595
Future Minimum Payments Due, 2018	212,431
Future Minimum Payments Due, 2019	189,130
Future Minimum Payments Due, 2020	169,953
Future Minimum Payments Due, 2021 and thereafter	581,370
Total minimum lease payments	1,444,289
Aircraft and Spare Engine Leases [Member]
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
remainder of 2016	50,986
Future Minimum Payments Due, 2017	194,607
Future Minimum Payments Due, 2018	177,717
Future Minimum Payments Due, 2019	158,818
Future Minimum Payments Due, 2020	150,842
Future Minimum Payments Due, 2021 and thereafter	520,857
Total minimum lease payments	1,253,827
Property Facility Leases [Member]
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
remainder of 2016	10,824
Future Minimum Payments Due, 2017	34,988
Future Minimum Payments Due, 2018	34,714
Future Minimum Payments Due, 2019	30,312
Future Minimum Payments Due, 2020	19,111
Future Minimum Payments Due, 2021 and thereafter	60,513
Total minimum lease payments	$ 190,462