Variable Interest Entities (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	6 Months Ended
	Jun. 30, 2012 Term_Loan Entity Aircraft Subsidiaries	Jun. 30, 2011 Term_Loan
Variable Interest Entities (Textual) [Abstract]
Number of VIE's consolidated	8
Number of Aircrafts	22
Number of subsidiaries	2
Percentage of common shares owned	95.00%
Limitation of trust risk to annual dividend	$ 2
Number of Irish Variable Interest Entities	2
Number of aircraft transferred to historical cost basis	13
Combined assets	$ 359,057
Combined Liabilities	72,068
Elimination of class E-1 securities by consolidation	337,292
Type of term loans	10
Period of term loan	12 years
Number of new airbuses	10
Number of VIE ECA Loans Repaid		1
Number of outstanding term loan	9
Net book value of flight equipment held for lease	745,564
Consolidated debt outstanding	$ 593,216