Commitments and Contingent Liabilities (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013 gal item
Total Committed Expenditures
Remaining months in 2013	$ 102,567
2014	471,337
2015	293,034
2016	184,094
2017	529,405
Thereafter	1,338,959
Total	2,919,396
Less: Committed Financing for Upcoming Aircraft Deliveries
Remaining months in 2013	76,110
2014	368,430
Total	444,540
Net Committed Expenditures
Remaining months in 2013	26,457
2014	102,907
2015	293,034
2016	184,094
2017	529,405
Thereafter	1,338,959
Total	2,474,856
Capital
Total Committed Expenditures
Remaining months in 2013	90,486
2014	421,472
2015	245,589
2016	147,824
2017	493,824
Thereafter	1,105,696
Total	2,504,891
Capital | Airbus A330-200
Commitments and Contingent Liabilities
Firm Orders, number of aircraft	9
Purchase Rights for number of additional aircraft	3
Capital | Airbus A330-200 | Rolls Royce spare engines
Commitments and Contingent Liabilities
Firm orders, number of spare engines	2
Capital | Airbus A350XWB-800
Commitments and Contingent Liabilities
Firm Orders, number of aircraft	6
Purchase Rights for number of additional aircraft	6
Capital | Airbus A350XWB-800 | Rolls Royce spare engines
Commitments and Contingent Liabilities
Firm orders, number of spare engines	2
Capital | Airbus A321neo aircraft
Commitments and Contingent Liabilities
Firm Orders, number of aircraft	16
Purchase Rights for number of additional aircraft	9
Capital | Airbus A321neo aircraft | Pratt and Whitney spare engines
Commitments and Contingent Liabilities
Firm orders, number of spare engines	2
Operating
Total Committed Expenditures
Remaining months in 2013	12,081
2014	49,865
2015	47,445
2016	36,270
2017	35,581
Thereafter	233,263
Total	$ 414,505