Other Assets (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Principal components of other assets
Debt investments	$ 0	$ 40,388
Deferred debt issuance costs, net of amortization of $54,146 and $56,609, respectively	53,065	55,087
Deferred federal income tax asset	21,954	22,207
Lease incentives and lease premiums, net of amortization of $26,902 and $29,250, respectively	60,716	62,822
Flight equipment held for sale	18,650	0
Other assets	14,988	6,260
Total other assets	169,373	186,764
Other Assets (Textual) [Abstract]
Amortization of deferred debt issuance costs	56,609	54,146
Amortization of lease incentives and lease premiums	$ 29,250	$ 26,902