Gross Proceeds From Sale Of Productive Assets

No definition available.

Name:	mesa_GrossProceedsFromSaleOfProductiveAssets
Namespace Prefix:	mesa_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Number of aircraft held for sale.

+ References

No definition available.

+ Details

Name:	mesa_NumberOfAircraftHeldForSale
Namespace Prefix:	mesa_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- 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

- Definition

Number of aircraft split up.

+ References

No definition available.

+ Details

Name:	mesa_NumberOfAircraftSplitUp
Namespace Prefix:	mesa_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of aircraft split up to airframes.

+ References

No definition available.

+ Details

Name:	mesa_NumberOfAircraftSplitUpToAirframes
Namespace Prefix:	mesa_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of aircraft split up to engines.

+ References

No definition available.

+ Details

Name:	mesa_NumberOfAircraftSplitUpToEngines
Namespace Prefix:	mesa_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of airframes to be sold.

+ References

No definition available.

+ Details

Name:	mesa_NumberOfAirframesToBeSold
Namespace Prefix:	mesa_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of airframes without engines.

+ References

No definition available.

+ Details

Name:	mesa_NumberOfAirframesWithoutEngines
Namespace Prefix:	mesa_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- 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

- Definition

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

+ References

+ Details

Name:	us-gaap_AssetImpairmentCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of assets held-for-sale that are not part of a disposal group.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 15
-Paragraph 4
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482309/360-10-15-4

+ Details

Name:	us-gaap_AssetsHeldForSaleNotPartOfDisposalGroup
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of assets held-for-sale that are not part of a disposal group, expected to be sold within a year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 852
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481372/852-10-55-10

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 15
-Paragraph 4
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482309/360-10-15-4

+ Details

Name:	us-gaap_AssetsHeldForSaleNotPartOfDisposalGroupCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- 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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_LongLivedAssetsHeldForSaleLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- 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

- Details

Name:	us-gaap_BalanceSheetLocationAxis=mesa_CurrentAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=mesa_NoncurrentAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=mesa_WithoutActivePurchaseAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	srt_AircraftTypeAxis=srt_CRJ900Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_AircraftTypeAxis=mesa_GEModelMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_AircraftTypeAxis=mesa_AirframesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=mesa_RASPROAircraftLeaseAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_AircraftTypeAxis=mesa_EnginesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_AircraftTypeAxis=mesa_EnginesTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_AircraftTypeAxis=mesa_EnginesThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_AircraftTypeAxis=mesa_EnginesFourMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_AircraftTypeAxis=mesa_EnginesFiveMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	srt_AircraftTypeAxis=mesa_EnginesSixMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_AircraftTypeAxis=mesa_EnginesOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_AircraftTypeAxis=mesa_EnginersSevenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_AircraftTypeAxis=mesa_EnginersEightMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_AircraftTypeAxis=srt_CRJ700Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Assets Held for Sale - Additional Information (Detail) $ in Thousands		12 Months Ended
	Apr. 03, 2025 Engine	Sep. 30, 2024 USD ($) Airframes Engines AirCraft	Sep. 30, 2023 USD ($) AirCraft	Sep. 30, 2022 USD ($)
Long Lived Assets Held For Sale [Line Items]
Asset impairment		$ 73,709	$ 54,343	$ 171,824
Impairment loss held for sale		73,700	50,600	$ 62,100
Aircraft held for sale current		$ 5,741	57,722
Number of aircraft split up to airframes \| Airframes		7
Number of aircraft split up to engines \| Engines		14
Aircraft held for sale		$ 86,605	$ 12,000
Number of engines to be sold \| Engines		55
Number of airframes to be sold \| Airframes		26
Current Assets [Member]
Long Lived Assets Held For Sale [Line Items]
Aircraft held for sale current		$ 5,700
Noncurrent Assets [Member]
Long Lived Assets Held For Sale [Line Items]
Aircraft held for sale		$ 86,600
Without Active Purchase Agreement [Member]
Long Lived Assets Held For Sale [Line Items]
Number of engines to be sold \| Engines		19
Number of airframes to be sold \| Airframes		26
Subsequent Event [Member]
Long Lived Assets Held For Sale [Line Items]
Number of engines to be sold \| Engine	23
CRJ-900 [Member]
Long Lived Assets Held For Sale [Line Items]
Number of aircraft held for sale \| AirCraft		8	15
Number of airframes without engines \| AirCraft		26
Number of aircraft sold \| AirCraft		15
Gross proceeds from sale of asset		$ 71,500
Number of aircraft split up \| AirCraft		7
Aircraft held for sale		$ 92,300
GE Model [Member]
Long Lived Assets Held For Sale [Line Items]
Number of aircraft held for sale \| AirCraft		77
Airframes [Member]
Long Lived Assets Held For Sale [Line Items]
Number of aircraft held for sale \| Airframes		26
Airframes [Member] \| RASPRO Aircraft Lease Agreement [Member]
Long Lived Assets Held For Sale [Line Items]
Number of aircraft sold \| Airframes		15
Gross proceeds from sale of asset		$ 18,800
Engines [Member]
Long Lived Assets Held For Sale [Line Items]
Number of aircraft held for sale \| Engines		55
Number of aircraft sold \| Engines		30
Gross proceeds from sale of asset		$ 19,500
29 Enginers [Member] \| RASPRO Aircraft Lease Agreement [Member]
Long Lived Assets Held For Sale [Line Items]
Number of aircraft sold \| Engines		29
Gross proceeds from sale of asset		$ 18,900
Remaining Engine [Member]
Long Lived Assets Held For Sale [Line Items]
Gross proceeds from sale of asset		$ 700
23 Engines [Member]
Long Lived Assets Held For Sale [Line Items]
Number of aircraft sold \| Engines		23
Gross proceeds from sale of asset		$ 11,500
3 Engines [Member] \| UST Loan [Member]
Long Lived Assets Held For Sale [Line Items]
Number of aircraft sold \| Engines		3
Gross proceeds from sale of asset		$ 1,500
12 Engines [Member]
Long Lived Assets Held For Sale [Line Items]
Number of aircraft sold \| Engines		12
Gross proceeds from sale of asset		$ 54,200
14 Enginers [Member]
Long Lived Assets Held For Sale [Line Items]
Number of aircraft sold \| Engines		14
Gross proceeds from sale of asset		$ 24,700
9 Enginers [Member]
Long Lived Assets Held For Sale [Line Items]
Number of aircraft sold \| Engines		9
Gross proceeds from sale of asset		$ 8,800
8 Enginers [Member]
Long Lived Assets Held For Sale [Line Items]
Number of aircraft sold \| Engines		8
Gross proceeds from sale of asset		$ 12,900
Proceeds from sale of asset		$ 4,400
CRJ-700 [Member]
Long Lived Assets Held For Sale [Line Items]
Number of aircraft held for sale \| AirCraft		2
Gross proceeds from sale of asset		$ 11,000