Commitments and Contingent Liabilities (Details 2) (USD $)	9 Months Ended				3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Credit Card Processing Agreements	Dec. 31, 2013 Credit Card Processing Agreements	Sep. 30, 2014 Enhanced Equipment Trust Certificates (EETC)	Sep. 30, 2014 Enhanced Equipment Trust Certificates (EETC) airbus_aircraft pass_through_trust	Dec. 31, 2013 Enhanced Equipment Trust Certificates (EETC) airbus_aircraft pass_through_trust	Dec. 31, 2013 Enhanced Equipment Trust Certificates (EETC) Class A pass-through trust	Dec. 31, 2013 Enhanced Equipment Trust Certificates (EETC) Class B pass-through trust
Commitments
Number of pass-through trusts							2
Aggregate principal amount issued							$ 444,500,000	$ 328,200,000	$ 116,300,000
Stated interest rate (as a percent)								3.90%	4.95%
Number of aircraft financed through loan						4	6
Proceeds from the issuance of the equipment notes					293,400,000
Restricted cash			5,000,000	5,000,000			16,000,000
Change in restricted cash	$ (14,434,000)	$ 16,000,000
Maximum limit of holdback (as a percent)			100.00%