Commitments (Details 2)
 6 Months Ended
Nov. 30, 2016
Schedule of Aircraft Commitments [Line Items]  
2017 (remainder) 2
2018 18
2019 17
2020 19
2021 13
Thereafter 22
Total 91
Boeing 777 Freighter [Member]  
Schedule of Aircraft Commitments [Line Items]  
2018 2
2019 2
2020 3
2021 3
Thereafter 6
Total 16
Boeing 767 Freighter [Member]  
Schedule of Aircraft Commitments [Line Items]  
2017 (remainder) 2
2018 16
2019 15
2020 16
2021 10
Thereafter 16
Total 75