Commitments and Contingencies - Future Minimum Lease Payments Under Noncancelable Operating Leases (Details) - Jun. 30, 2015 $ in Thousands	USD ($) leases
Capital Leases, Future Minimum Payments, Net Minimum Payments, Rolling Maturity [Abstract]
remainder of 2015	$ 722
Future Minimum Payments Due, 2016	1,044
Future Minimum Payments Due, 2017	44
Future Minimum Payments Due, 2018	44
Future Minimum Payments Due, 2019	12
Future Minimum Payments Due, 2020 and thereafter	0
Total minimum lease payments	1,866
Less amount representing interest	114
Present value of minimum lease payments	1,752
Less current portion	1,249
Long-term portion	503
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
remainder of 2015	124,237
Future Minimum Payments Due, 2016	240,183
Future Minimum Payments Due, 2017	224,055
Future Minimum Payments Due, 2018	200,307
Future Minimum Payments Due, 2019	169,847
Future Minimum Payments Due, 2020 and thereafter	674,791
Total minimum lease payments	$ 1,633,420
Quick Engine Change Kit [Member]
Capital Leased Assets [Line Items]
Number of Capital Leases | leases	2
Capital Leases of Lessee, Lease Term	3 years
Aircraft and Spare Engine Leases [Member]
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
remainder of 2015	$ 107,632
Future Minimum Payments Due, 2016	213,120
Future Minimum Payments Due, 2017	196,610
Future Minimum Payments Due, 2018	172,885
Future Minimum Payments Due, 2019	144,774
Future Minimum Payments Due, 2020 and thereafter	596,581
Total minimum lease payments	1,431,602
Property Facility Leases [Member]
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
remainder of 2015	16,605
Future Minimum Payments Due, 2016	27,063
Future Minimum Payments Due, 2017	27,445
Future Minimum Payments Due, 2018	27,422
Future Minimum Payments Due, 2019	25,073
Future Minimum Payments Due, 2020 and thereafter	78,210
Total minimum lease payments	$ 201,818