Commitments (Details 2)	Aug. 31, 2011
Schedule of Aircraft Commitments [Line Items]
2012 (remainder)	21
2013	11
2014	7
2015	3
2016	3
Thereafter	7
Total	52
Boeing 777 Freighter [Member]
Schedule of Aircraft Commitments [Line Items]
2012 (remainder)	6
2013	6
2014	7
2015	3
2016	3
Thereafter	7
Total	32
Boeing 757 [Member]
Schedule of Aircraft Commitments [Line Items]
2012 (remainder)	15
2013	5
Total	20