Commitments and Contingencies - Future Minimum Lease Payments Under Noncancelable Operating Leases (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013 leases
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Future Minimum Payments Due, Remainder of Fiscal Year	$ 159,672
Future Minimum Payments Due, 2015	210,545
Future Minimum Payments Due, 2016	202,781
Future Minimum Payments Due, 2017	180,817
Future Minimum Payments Due, 2018	154,533
Future Minimum Payments Due, 2019 and thereafter	585,341
Total minimum lease payments	1,493,689
Leases, Capital [Abstract]
Capital Leases, Future Minimum Payments Due, Remainder of Fiscal Year	1,400
Capital Leases, Future Minimum Payments Due in Two Years	1,200
Capital Leases, Future Minimum Payments Due in Three Years	1,000
Capital Leases, Future Minimum Payments Due in Four Years	0
Capital Leases, Future Minimum Payments Due in Five Years	0
Capital Leases, Future Minimum Payments Due Thereafter	0
Capital Leases, Future Minimum Payments Due	3,600
Capital Leases, Future Minimum Payments, Interest Included in Payments	366
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments	3,234
Capital Lease Obligations, Current	1,448
Capital Lease Obligations, Long Term	1,786
Aircraft and Spare Engine Leases [Member]
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Future Minimum Payments Due, Remainder of Fiscal Year	144,327
Future Minimum Payments Due, 2015	192,998
Future Minimum Payments Due, 2016	191,173
Future Minimum Payments Due, 2017	171,977
Future Minimum Payments Due, 2018	148,044
Future Minimum Payments Due, 2019 and thereafter	560,931
Total minimum lease payments	1,409,450
Property Facility Leases [Member]
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Future Minimum Payments Due, Remainder of Fiscal Year	15,345
Future Minimum Payments Due, 2015	17,547
Future Minimum Payments Due, 2016	11,608
Future Minimum Payments Due, 2017	8,840
Future Minimum Payments Due, 2018	6,489
Future Minimum Payments Due, 2019 and thereafter	24,410
Total minimum lease payments	$ 84,239
Quick Engine Change Kit [Member]
Schedule of Future Minimum Lease Payments for Capital and Operating Leases [Table Text Block] [Line Items]
Number of Capital Leases		2
Capital Leases of Lessee, Lease Term	3 years
Airbus [Member]
Schedule of Future Minimum Lease Payments for Capital and Operating Leases [Table Text Block] [Line Items]
Number of Aircraft without Secured Financing Commitments Scheduled for Delivery (in aircraft)	105
Airbus [Member] | Fourth Quarter of 2014 [Member]
Schedule of Future Minimum Lease Payments for Capital and Operating Leases [Table Text Block] [Line Items]
Number of Aircraft without Secured Financing Commitments Scheduled for Delivery (in aircraft)	4
Airbus [Member] | 2015 [Member]
Schedule of Future Minimum Lease Payments for Capital and Operating Leases [Table Text Block] [Line Items]
Number of Aircraft without Secured Financing Commitments Scheduled for Delivery (in aircraft)	11