Fair Value Measurements (Details 2) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Carrying amounts and fair values of financial instruments
Carrying Amount of Asset (Liability)	$ (3,515,966)	$ (3,598,676)
Securitizations and term debt financings
Carrying amounts and fair values of financial instruments
Carrying Amount of Asset (Liability)	(1,016,112)	(1,082,368)
Fair Value of Asset (Liability)	(908,335)	(962,960)
ECA term financings
Carrying amounts and fair values of financial instruments
Carrying Amount of Asset (Liability)	(639,866)	(652,916)
Fair Value of Asset (Liability)	(657,864)	(671,966)
Bank financings
Carrying amounts and fair values of financial instruments
Carrying Amount of Asset (Liability)	(109,375)	(112,750)
Fair Value of Asset (Liability)	(112,497)	(116,272)
Senior Notes
Carrying amounts and fair values of financial instruments
Carrying Amount of Asset (Liability)	(1,750,613)	(1,750,642)
Fair Value of Asset (Liability)	$ (1,961,783)	$ (1,905,565)