XML 70 R56.htm IDEA: XBRL DOCUMENT v3.22.2
Leases - Additional Information (Detail)
$ in Millions
3 Months Ended 9 Months Ended
Jun. 30, 2022
USD ($)
Air-craft
Jun. 30, 2021
USD ($)
Jun. 30, 2022
USD ($)
Air-craft
Jun. 30, 2021
USD ($)
Leases [Abstract]        
Number of leased aircraft | Air-craft 20   20  
Aggregate rental expense under all operating aircraft, equipment and facility leases $ 10.8 $ 11.3 $ 33.1 $ 34.0
Weighted average remaining lease term Operating leases 3 years 9 months 18 days   3 years 9 months 18 days  
Weighted average discount rate Operating leases 4.50%   4.50%  
Impairment of certain operating lease ROU assets     $ 0.2