XML 165 R70.htm IDEA: XBRL DOCUMENT
v3.25.2

Subsequent Events - Additional Information (Detail) $ in Millions |  |  |  |  |  |  |  |  | 1 Months Ended | 3 Months Ended | 9 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Jul. 24, 2025 USD ($) ENGINE | Apr. 04, 2025 | Apr. 03, 2025 USD ($) AIRFRAMES AIRCRAFT ENGINE | Mar. 18, 2025 | Dec. 31, 2024 USD ($) AIRCRAFT | Dec. 24, 2024 USD ($) AIRFRAMES | Dec. 23, 2024 USD ($) | Oct. 01, 2024 USD ($) AIRCRAFT AIRFRAMES | Dec. 31, 2015 USD ($) | Jun. 30, 2025 USD ($) | Jun. 30, 2025 AIRCRAFT | Sep. 30, 2024 USD ($) ENGINE | Sep. 30, 2023 USD ($) | Sep. 30, 2022 USD ($) | Dec. 30, 2024 USD ($)
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of engines to be sold | ENGINE |  |  |  |  |  |  |  |  |  |  |  | 55 |  |  |
Impairment loss |  |  |  |  |  |  |  |  |  | $ 0.1 |  | $ 73.7 | $ 50.6 | $ 62.1 |
E-175 Aircraft [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of aircraft sold | AIRCRAFT |  |  |  |  |  |  |  |  |  |  | 18 |  |  |  |
Remaining balance |  |  |  |  |  |  |  |  | $ 73.4 |  |  |  |  |  |
CRJ-700 Aircraft [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of aircraft sold | AIRCRAFT |  |  |  |  |  |  |  | 2 |  |  |  |  |  |  |
UST Loan [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Minimum collateral coverage ratio |  |  |  | 0.91 |  |  | 0.99 |  |  |  |  |  |  |  |
Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of increase in CPA block hour rates |  | 3.00% |  |  |  |  |  |  |  |  |  |  |  |  |
Number of engines to be sold | ENGINE |  |  | 23 |  |  |  |  |  |  |  |  |  |  |  |
Remaining balance |  |  |  |  |  |  |  | $ 73.4 |  |  |  |  |  |  |
Proceeds from Sale of Property, Plant, and Equipment | $ 4.6 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Member] | United Capacity Purchase Agreement [Member] | United Airlines Inc [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common stock issued equivalent percentage of issued and outstanding capital stock |  | 6.00% |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Member] | Engines Held For Sale [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Impairment Loss Held For Sale |  |  | $ 14.7 |  |  |  |  | $ 25.4 |  |  |  |  |  |  |
Subsequent Event [Member] | United Revolving Credit Facility [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loan balance forgiven |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 4.5
Subsequent Event [Member] | E-175 Aircraft [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of aircraft sold | AIRCRAFT |  |  |  |  |  |  |  | 2 |  |  |  |  |  |  |
Subsequent Event [Member] | E-175 Aircraft [Member] | Aircraft Purchase Agreement [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Expected gross proceeds from sale of asset |  |  |  |  | $ 227.7 |  |  |  |  |  |  |  |  |  |
Expected proceeds from sale of asset |  |  |  |  | $ 84.7 |  |  |  |  |  |  |  |  |  |
Number of aircraft classified as assets held for sale | AIRCRAFT |  |  |  |  |  |  |  | 18 |  |  |  |  |  |  |
Number of aircraft sold | AIRCRAFT |  |  |  |  | 18 |  |  |  |  |  |  |  |  |  |
Subsequent Event [Member] | E-175 Aircraft [Member] | United Aircraft Purchase Agreement [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Expected gross proceeds from sale of asset |  |  |  |  |  |  |  | $ 84.7 |  |  |  | $ 227.7 |  |  |
Expected proceeds from sale of asset |  |  | $ 16.3 |  |  |  |  |  |  |  |  |  |  |  |
Number of aircraft classified as assets held for sale | AIRCRAFT |  |  |  |  | 18 |  |  | 18 |  |  |  |  |  |  |
Gross proceeds from sale of asset |  |  |  |  |  |  |  | $ 120.6 |  |  |  |  |  |  |
Number of aircraft sold | AIRCRAFT |  |  | 23 |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Member] | C R J 900 Airframes [Member] | Aircraft Purchase Agreement [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of aircraft sold | AIRFRAMES |  |  |  |  |  |  |  | 4 |  |  |  |  |  |  |
Subsequent Event [Member] | C R J 900 Airframes [Member] | Airframe Purchase Agreement [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of aircraft classified as assets held for sale | AIRFRAMES |  |  |  |  |  | 29 |  |  |  |  |  |  |  |  |
Gross proceeds from sale of asset |  |  | $ 9.1 |  |  |  | $ 19.0 |  |  |  |  |  |  |  |
Number of aircraft sold | AIRFRAMES |  |  | 14 |  |  | 15 |  |  |  |  |  |  |  |  |
Impairment loss |  |  |  |  |  | $ 6.7 |  |  |  |  |  |  |  |  |
Subsequent Event [Member] | CRJ-700 Aircraft [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Gross proceeds from sale of asset |  |  |  |  |  |  |  | $ 11.0 |  |  |  |  |  |  |
Net proceeds from sale of asset |  |  |  |  |  |  |  | $ 6.8 |  |  |  |  |  |  |
Subsequent Event [Member] | CF34-8C Engines [Member] | Airframe Purchase Agreement [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of aircraft sold | AIRFRAMES |  |  |  |  |  |  |  | 18 |  |  |  |  |  |  |
Subsequent Event [Member] | UST Loan [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Minimum collateral coverage ratio |  |  |  |  |  |  | 1.55 |  |  |  |  |  |  |  |
Number of engine sold | ENGINE | 5 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Member] | UST Loan [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Minimum collateral coverage ratio |  |  |  | 0.91 |  |  | 0.99 |  |  |  |  |  |  |  |
Subsequent Event [Member] | UST Loan [Member] | Aircraft Purchase Agreement [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Gross proceeds from sale of asset |  |  |  |  |  |  |  | $ 22.4 |  |  |  |  |  |  |
Repayments of debt |  |  |  |  |  |  |  | $ 21.0 |  |  |  |  |  |  |
Subsequent Event [Member] | UST Loan [Member] | C R J 900 Airframes [Member] | Airframe Purchase Agreement [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Gross proceeds from sale of asset |  |  | $ 28.1 |  |  |  |  |  |  |  |  |  |  |  |

X
- Definition Common stock issued equivalent percentage of issued and outstanding capital stock. + References No definition available. + Details
Name: | mesa_CommonStockIssuedEquivalentPercentageOfIssuedAndOutstandingCapitalStock
Namespace Prefix: | mesa_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Expected gross proceeds from sale of productive assets. + References No definition available. + Details
Name: | mesa_ExpectedGrossProceedsFromSaleOfProductiveAssets
Namespace Prefix: | mesa_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Expected proceeds from sale of productive assets. + References No definition available. + Details
Name: | mesa_ExpectedProceedsFromSaleOfProductiveAssets
Namespace Prefix: | mesa_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Gross Proceeds From Sale Of Productive Assets + References No definition available. + Details
Name: | mesa_GrossProceedsFromSaleOfProductiveAssets
Namespace Prefix: | mesa_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Impairment loss held for sale. + References No definition available. + Details
Name: | mesa_ImpairmentLossHeldForSale
Namespace Prefix: | mesa_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Loan balance forgiven. + References No definition available. + Details
Name: | mesa_LoanBalanceForgiven
Namespace Prefix: | mesa_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Minimum collateral coverage ratio 1. + References No definition available. + Details
Name: | mesa_MinimumCollateralCoverageRatio1
Namespace Prefix: | mesa_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of aircraft classified as assets held for sale. + References No definition available. + Details
Name: | mesa_NumberOfAircraftClassifiedAsAssetsHeldForSale
Namespace Prefix: | mesa_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of aircraft sold. + References No definition available. + Details
Name: | mesa_NumberOfAircraftSold
Namespace Prefix: | mesa_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of engine sold. + References No definition available. + Details
Name: | mesa_NumberOfEngineSold
Namespace Prefix: | mesa_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of engines to be sold. + References No definition available. + Details
Name: | mesa_NumberOfEnginesToBeSold
Namespace Prefix: | mesa_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of increase in CPA block hour rates. + References No definition available. + Details
Name: | mesa_PercentageOfIncreaseInCPABlockHourRates
Namespace Prefix: | mesa_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Remaining balance + References No definition available. + Details
Name: | mesa_RemainingBalance
Namespace Prefix: | mesa_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The aggregate amount of write-downs for impairments recognized during the period for long-lived assets held for abandonment, exchange or sale. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 45 -Paragraph 28 -Subparagraph (b) -SubTopic 10 -Topic 230 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-28 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 100 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-100 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 360 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 15 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482130/360-10-45-15 + Details
Name: | us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The cash inflow from the sale of property, plant and equipment (capital expenditures), software, and other intangible assets. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 230 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 12 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-12 + Details
Name: | us-gaap_ProceedsFromSaleOfProductiveAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The cash inflow from the sale of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 230 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 12 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-12 + Details
Name: | us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of cash outflow for short-term and long-term debt. Excludes payment of lease obligation. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 230 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 15 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-15 + Details
Name: | us-gaap_RepaymentsOfDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 830 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481674/830-30-50-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 855 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483399/855-10-50-2 + Details
Name: | us-gaap_SubsequentEventLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | srt_AircraftTypeAxis=mesa_E175AircraftMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_AircraftTypeAxis=mesa_CRJ700AircraftMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=mesa_UstLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=mesa_UnitedCapacityPurchaseAgreementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_MajorCustomersAxis=mesa_UnitedAirlinesIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TypeOfArrangementAxis=mesa_EnginesHeldForSaleMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditFacilityAxis=mesa_UnitedRevolvingCreditFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TypeOfArrangementAxis=mesa_AircraftPurchaseAgreementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TypeOfArrangementAxis=mesa_UnitedAircraftPurchaseAgreementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_AircraftTypeAxis=mesa_CRJ900AirframesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TypeOfArrangementAxis=mesa_AirframePurchaseAgreementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_AircraftTypeAxis=mesa_CF34-8CEnginesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |