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Long-Term Debt, Finance Leases and Other Borrowings - Schedule of Long-term Debt (Parenthetical) (Detail) |  |  |  |  | 1 Months Ended | 3 Months Ended | 9 Months Ended | 12 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Nov. 12, 2020 USD ($) Air-craft | Oct. 30, 2020 USD ($) | Sep. 27, 2019 USD ($) | Sep. 25, 2019 USD ($) | Jun. 30, 2019 USD ($) Airfleet | Jan. 31, 2019 USD ($) | Jun. 30, 2018 USD ($) Air-craft | Feb. 28, 2018 Engine | Dec. 31, 2017 USD ($) Air-craft | Jun. 30, 2020 USD ($) | Dec. 31, 2019 | Jun. 30, 2021 USD ($) | Jun. 30, 2020 USD ($) | Sep. 30, 2020 | Sep. 30, 2019 USD ($) | Sep. 30, 2018 USD ($) | Sep. 30, 2017 USD ($) | Sep. 30, 2016 USD ($) Air-craft | Sep. 30, 2015 USD ($) Air-craft | Nov. 14, 2020 USD ($) | Nov. 13, 2020 USD ($) | Sep. 30, 2014 USD ($) Airfleet | Sep. 30, 2007 USD ($) Airfleet
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from long-term debt |  |  |  |  |  |  |  |  |  |  |  | $ 195,000,000 | $ 23,000,000 |  |  |  |  |  |  |  |  |  |
Loan Agreement [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of aircraft financed | Air-craft | 44 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Repayments of long term debt | $ 167,700,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Secured term loan facility, amount borrowed |  | $ 43,000,000.0 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Secured term loan facility, additional amount borrowed |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 152,000,000.0 |  |
Notes Payable to Financial Institution, Collateralized by the Underlying Aircraft, Due 2022 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument maturity year |  |  |  |  |  |  |  |  |  |  |  | 2022 |  | 2022 |  |  |  |  |  |  |  |  |
Notes Payable to Financial Institution, Collateralized by the Underlying Aircraft, Due 2022 [Member] | CRJ-900 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of aircraft refinanced | Airfleet |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3
Notes Payable to Financial Institution, Collateralized by the Underlying Aircraft, Due 2022 [Member] | CRJ-700 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of aircraft refinanced | Airfleet |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3
Notes Payable to Financial Institution, Collateralized by the Underlying Aircraft, Due 2022 [Member] | Three C- R- J-900 and Three C- R- J-700 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, face amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 120,300,000
Long term debt interest rate description |  |  |  |  |  |  |  |  |  |  |  | monthly LIBOR plus 2.25% |  |  |  |  |  |  |  |  |  |  |
Notes Payable to Financial Institution, Collateralized by the Underlying Aircraft, Due 2022 [Member] | Three C- R- J-900 and Three C- R- J-700 [Member] | LIBOR [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt, basis spread on variable rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2.25% |  |  |  |  |  |
Notes Payable to Financial Institution, Collateralized by the Underlying Aircraft, Due 2022 [Member] | Ten C- R- J-900 Aircraft [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, face amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 88,400,000 |
Long term debt interest rate description |  |  |  |  |  |  |  |  |  |  |  | monthly LIBOR plus 1.95% |  |  |  |  |  |  |  |  |  |  |
Number of aircraft financed | Airfleet |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 10 |
Long term debt interest rate percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1.95% |
Repayments of long term debt |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 40,000,000.0 |  |  |  |  |  |  |
Notes Payable to Financial Institution, Collateralized by the Underlying Aircraft, Due 2024 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument maturity year |  |  |  |  |  |  |  |  |  |  |  | 2024 |  | 2024 |  |  |  |  |  |  |  |  |
Notes Payable to Financial Institution, Collateralized by the Underlying Aircraft, Due 2024 [Member] | Eight C- R- J-900 Aircraft [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, face amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 114,500,000 |
Number of aircraft financed | Airfleet |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 8 |
Long term debt interest rate percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 5.00% |
Senior and Subordinated Notes Payable to Secured Parties, Collateralized by the Underlying Aircraft, Due 2027 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument maturity year |  |  |  |  |  |  |  |  |  |  |  | 2027 |  | 2027 |  |  |  |  |  |  |  |  |
Senior and Subordinated Notes Payable to Secured Parties, Collateralized by the Underlying Aircraft, Due 2027 [Member] | CRJ-900 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, face amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 170,200,000 |  |  |  |
Number of aircraft financed | Air-craft |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 7 |  |  |  |
Notes Payable to Secured Parties, Collateralized by the Underlying Aircraft, Due 2028 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument maturity year |  |  |  |  |  |  |  |  |  |  |  | 2028 |  | 2028 |  |  |  |  |  |  |  |  |
Notes Payable to Secured Parties, Collateralized by the Underlying Aircraft, Due 2028 [Member] | Ten E-175 Aircraft [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, face amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 246,000,000.0 |  |  |  |  |
Number of aircraft financed | Air-craft |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 10 |  |  |  |  |
Notes Payable to Secured Parties, Collateralized by the Underlying Aircraft, Due 2028 [Member] | Ten E-175 Aircraft [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt interest rate percentage |  |  |  |  |  |  |  |  |  |  |  | 4.75% |  |  |  |  |  |  |  |  |  |  |
Notes Payable to Secured Parties, Collateralized by the Underlying Aircraft, Due 2028 [Member] | Ten E-175 Aircraft [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt interest rate percentage |  |  |  |  |  |  |  |  |  |  |  | 6.25% |  |  |  |  |  |  |  |  |  |  |
Senior and Subordinated Notes Payable to Secured Parties, Collateralized by the Underlying Aircraft, Due 2028 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument maturity year |  |  |  |  |  |  |  |  |  |  |  | 2028 |  | 2028 |  |  |  |  |  |  |  |  |
Senior and Subordinated Notes Payable to Secured Parties, Collateralized by the Underlying Aircraft, Due 2028 [Member] | Eight E-175 Aircraft [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of aircraft refinanced | Air-craft |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 8 |  |  |  |  |
Debt instrument, face amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 195,300,000 |  |  |  |  |
Senior and Subordinated Notes Payable to Secured Parties, Collateralized by the Underlying Aircraft, Due 2022 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument maturity year |  |  |  |  |  |  |  |  |  |  |  | 2022 |  | 2022 |  |  |  |  |  |  |  |  |
Senior and Subordinated Notes Payable to Secured Parties, Collateralized by the Underlying Aircraft, Due 2022 [Member] | CRJ-900 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument maturity year |  |  |  |  |  |  |  |  |  |  |  | 2022 |  | 2022 |  |  |  |  |  |  |  |  |
Number of aircraft refinanced | Air-craft |  |  |  |  |  |  | 6 |  | 9 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, face amount |  |  |  |  |  |  | $ 27,500,000 |  | $ 74,900,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of aircraft financed | Air-craft |  |  |  |  |  |  | 9 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Senior and Subordinated Notes Payable to Secured Parties, Collateralized by the Underlying Aircraft, Due 2022 [Member] | CRJ-900 [Member] | Capital Lease Obligations [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, face amount |  |  |  |  |  |  | $ 69,600,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Notes Payable to Financial Institution, Collateralized by the Underlying Equipment, Due 2020 [Member] | Flight Equipment Maintenance [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument maturity year |  |  |  |  |  |  |  |  |  |  |  | 2020 |  | 2020 |  |  |  |  |  |  |  |  |
Notes Payable to Financial Institution, Collateralized by the Underlying Equipment, Due 2020 [Member] | Flight Equipment Maintenance [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, face amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 26,100,000 | $ 26,100,000 | $ 26,100,000 | $ 26,100,000 |  |  |  |  |
Long term debt interest rate description |  |  |  |  |  |  |  |  |  |  |  | three-month LIBOR plus a spread ranging from 2.93% to 3.21% |  |  |  |  |  |  |  |  |  |  |
Notes Payable to Financial Institution, Collateralized by the Underlying Equipment, Due 2020 [Member] | Flight Equipment Maintenance [Member] | LIBOR [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt, basis spread on variable rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2.93% | 2.93% | 2.93% | 2.93% |  |  |  |  |
Notes Payable to Financial Institution, Collateralized by the Underlying Equipment, Due 2020 [Member] | Flight Equipment Maintenance [Member] | LIBOR [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt, basis spread on variable rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3.21% | 3.21% | 3.21% | 3.21% |  |  |  |  |
Notes Payable to Financial Institution Due 2020 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument maturity year |  |  |  |  |  |  |  |  |  |  |  | 2020 |  | 2020 |  |  |  |  |  |  |  |  |
Notes Payable to Financial Institution Due 2020 [Member] | Flight Equipment Maintenance [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, face amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 10,200,000 | $ 10,200,000 |  |  |  |
Long term debt interest rate description |  |  |  |  |  |  |  |  |  |  |  | three-month LIBOR plus 3.07% |  |  |  |  |  |  |  |  |  |  |
Notes Payable to Financial Institution Due 2020 [Member] | Flight Equipment Maintenance [Member] | LIBOR [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt interest rate percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3.07% | 3.07% |  |  |  |
Other Obligations Due to Financial Institution, Collateralized by the Underlying Equipment, Due 2023 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument maturity year |  |  |  |  |  |  |  |  |  |  |  | 2023 |  | 2023 |  |  |  |  |  |  |  |  |
Imputed interest |  |  |  |  |  |  |  | 9.128% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of spare engines leased | Engine |  |  |  |  |  |  |  | 2 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Notes Payable to Financial Institution, Collateralized by the Underlying Equipment, Due 2024 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument maturity year |  |  |  |  |  |  |  |  |  |  |  | 2024 |  | 2024 |  |  |  |  |  |  |  |  |
Notes Payable to Financial Institution, Collateralized by the Underlying Equipment, Due 2024 [Member] | Flight Equipment Maintenance [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, face amount |  |  |  |  |  | $ 91,200,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt interest rate description |  |  |  |  |  |  |  |  |  |  |  | monthly LIBOR plus 3.10% |  |  |  |  |  |  |  |  |  |  |
Notes Payable to Financial Institution, Collateralized by the Underlying Equipment, Due 2024 [Member] | Flight Equipment Maintenance [Member] | LIBOR [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt, basis spread on variable rate |  |  |  |  |  | 3.10% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Notes Payable to Financial Institution, Collateralized by the Underlying Aircraft, Due 2023 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument maturity year |  |  |  |  |  |  |  |  |  |  |  | 2023 |  | 2023 |  |  |  |  |  |  |  |  |
Notes Payable to Financial Institution, Collateralized by the Underlying Aircraft, Due 2023 [Member] | CRJ-700 Aircraft [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, face amount |  |  |  |  | $ 70,000,000.0 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt interest rate description |  |  |  |  |  |  |  |  |  |  |  | monthly LIBOR plus 5.00% |  |  |  |  |  |  |  |  |  |  |
Number of aircraft financed | Airfleet |  |  |  |  | 10 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Notes Payable to Financial Institution, Collateralized by the Underlying Aircraft, Due 2023 [Member] | CRJ-700 Aircraft [Member] | LIBOR [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt, basis spread on variable rate |  |  |  |  | 5.25% |  |  |  |  |  | 5.00% |  |  |  | 5.25% |  |  |  |  |  |  |  |
Notes Payable to Financial Institution Due 2023 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument maturity year |  |  |  |  |  |  |  |  |  |  |  | 2023 |  | 2023 |  |  |  |  |  |  |  |  |
Notes Payable to Financial Institution Due 2023 [Member] | Flight Equipment Maintenance [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, face amount |  |  | $ 8,000,000.0 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt interest rate description |  |  |  |  |  |  |  |  |  |  |  | monthly LIBOR plus 5.00% |  |  |  |  |  |  |  |  |  |  |
Notes Payable to Financial Institution Due 2023 [Member] | Flight Equipment Maintenance [Member] | LIBOR [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt, basis spread on variable rate |  |  | 5.25% |  |  |  |  |  |  |  | 5.00% |  |  |  | 5.25% |  |  |  |  |  |  |  |
Notes Payable to Financial Institution Due 2025 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument maturity year |  |  |  |  |  |  |  |  |  |  |  | 2025 |  | 2025 |  |  |  |  |  |  |  |  |
Senior Notes Due Two Thousand Twenty Seven [Member] | CRJ-900 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, face amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 151,000,000.0 |  |  |  |
Long term debt interest rate description |  |  |  |  |  |  |  |  |  |  |  | monthly LIBOR plus 2.71% |  |  |  |  |  |  |  |  |  |  |
Senior Notes Due Two Thousand Twenty Seven [Member] | CRJ-900 [Member] | LIBOR [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt, basis spread on variable rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2.71% |  |  |  |
Subordinated Notes Due Two Thousand Twenty Seven [Member] | CRJ-900 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Imputed interest |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 6.25% |  |  |  |
Debt discount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 8,100,000 |  |  |  |
Senior Notes Due 2008 [Member] | Eight E-175 Aircraft [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt interest rate description |  |  |  |  |  |  |  |  |  |  |  | three-month LIBOR plus a spread ranging from 2.20% to 2.32% |  |  |  |  |  |  |  |  |  |  |
Senior Notes Due 2008 [Member] | Eight E-175 Aircraft [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, face amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 172,000,000.0 |  |  |  |  |
Senior Notes Due 2008 [Member] | Eight E-175 Aircraft [Member] | LIBOR [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt, basis spread on variable rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2.20% |  |  |  |  |
Senior Notes Due 2008 [Member] | Eight E-175 Aircraft [Member] | LIBOR [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt, basis spread on variable rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2.32% |  |  |  |  |
Subordinated Notes Due 2008 [Member] | Eight E-175 Aircraft [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt interest rate percentage |  |  |  |  |  |  |  |  |  |  |  | 4.50% |  |  |  |  |  |  |  |  |  |  |
Senior Notes Due 2020 [Member] | CRJ-900 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, face amount |  |  |  |  |  |  | $ 65,800,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt, basis spread on variable rate |  |  |  |  |  |  | 3.50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Senior Notes Due 2020 [Member] | CRJ-900 [Member] | LIBOR [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt interest rate description |  |  |  |  |  |  |  |  |  |  |  | three-month LIBOR plus 3.50% |  |  |  |  |  |  |  |  |  |  |
Subordinated Notes Due 2020 [Member] | CRJ-900 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, face amount |  |  |  |  |  |  | $ 29,800,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt, basis spread on variable rate |  |  |  |  |  |  | 7.50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subordinated Notes Due 2020 [Member] | CRJ-900 [Member] | LIBOR [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt interest rate description |  |  |  |  |  |  |  |  |  |  |  | three-month LIBOR plus 7.50% |  |  |  |  |  |  |  |  |  |  |
Senior Notes due Two Thousand Twenty Two [Member] | CRJ-900 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, face amount |  |  |  |  |  |  |  |  | $ 46,900,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt interest rate description |  |  |  |  |  |  |  |  |  |  |  | three-month LIBOR plus 3.50% |  |  |  |  |  |  |  |  |  |  |
Senior Notes due Two Thousand Twenty Two [Member] | CRJ-900 [Member] | LIBOR [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt, basis spread on variable rate |  |  |  |  |  |  |  |  | 3.50% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subordinated Notes DueTwoThousandTwentyTwo [Member] | CRJ-900 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt interest rate description |  |  |  |  |  |  |  |  |  |  |  | three-month LIBOR plus 4.50% |  |  |  |  |  |  |  |  |  |  |
Subordinated Notes DueTwoThousandTwentyTwo [Member] | CRJ-900 [Member] | LIBOR [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt interest rate percentage |  |  |  |  |  |  |  |  | 4.50% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Working Capital Draw Loan [Member] | Revolving Credit Facility [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, face amount |  |  |  | $ 35,000,000.0 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt interest rate description |  |  |  |  |  |  |  |  |  |  |  | one-month LIBOR plus 3.75% |  |  |  |  |  |  |  |  |  |  |
Term loan, term |  |  |  | 3 years |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, expiration year and month |  |  |  | 2022-09 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from long-term debt |  |  |  |  |  |  |  |  |  | $ 23,000,000.0 |  | $ 22,900,000 |  |  |  |  |  |  |  |  |  |  |
Working Capital Draw Loan [Member] | LIBOR [Member] | Revolving Credit Facility [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt, basis spread on variable rate |  |  |  | 3.75% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Secured Term Loan Facility [Member] | Loan Agreement [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt, basis spread on variable rate |  | 3.50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long term debt interest rate description |  |  |  |  |  |  |  |  |  |  |  | three-month LIBOR plus 3.50% |  |  |  |  |  |  |  |  |  |  |
Secured term loan facility, maximum borrowing capacity |  | $ 200,000,000.0 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Secured term loan facility, amount borrowed |  | $ 43,000,000.0 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Secured term loan facility, additional amount borrowed |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 0 | $ 152,000,000.0 |  |
Debt instrument, maturity date |  |  |  |  |  |  |  |  |  |  |  | Oct. 30, 2025 |  |  |  |  |  |  |  |  |  |  |

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- Definition Number of aircraft financed. + References No definition available. + Details
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- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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- Definition Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(2)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
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