Commitments (Details 2)	Aug. 31, 2013
Schedule of Aircraft Commitments [Line Items]
2014 (remainder)	22
2015	23
2016	12
2017	10
2018	12
Thereafter	18
Total	97
Boeing 777 Freighter [Member]
Schedule of Aircraft Commitments [Line Items]
2014 (remainder)	2
2016	2
2018	2
Thereafter	14
Total	20
Boeing 757 [Member]
Schedule of Aircraft Commitments [Line Items]
2014 (remainder)	16
2015	11
Total	27
Boeing 767 Freighter [Member]
Schedule of Aircraft Commitments [Line Items]
2014 (remainder)	4
2015	12
2016	10
2017	10
2018	10
Thereafter	4
Total	50