Commitments and Contingencies - Commitments (Details) (USD $)	3 Months Ended	9 Months Ended
	Jun. 30, 2012	Sep. 30, 2012 aircraft_engine	Dec. 31, 2011
Commitments and Contingencies Disclosure [Abstract]
Number of spare aircraft engines ordered (in aircraft engine)		3
Number of spare aircraft engines entered into sale and leaseback agreement		2
Amount of credit card holdback		$ 0
Maximum potential exposure to cash holdbacks from credit card processors		152,700,000	115,200,000
Interest included in cash payment to pre-IPO stockholders pursuant to tax receivable agreement	300,000
Cash payment including interest to pre-IPO stockholders pursuant to tax receivable agreement	27,200,000
Aircraft and Related Flight Equipment [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Committed expenditures, remiander of 2012		84,000,000
Committed expenditures, 2013		324,000,000
Committed expenditures, 2014		348,000,000
Committed expenditures, 2015		520,000,000
Committed expenditures, 2016		511,000,000
Committed expenditures, 2017 and beyond		2,960,000,000
Reservation System Provider [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Committed expenditures, remiander of 2012		700,000
Committed expenditures, 2013		3,100,000
Committed expenditures, 2014		3,700,000
Committed expenditures, 2015		3,700,000
Committed expenditures, 2016		3,700,000
Committed expenditures, 2017 and beyond		$ 6,200,000
Airbus A320 [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Number of aircraft ordered (in aircraft)		101
Airbus A320, current model [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Number of aircraft ordered (in aircraft)		56
Airbus A320 NEO [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Number of aircraft ordered (in aircraft)		45