Additional collateral coverage ratio.

No definition available.

Name:	mesa_AdditionalCollateralCoverageRatio1
Namespace Prefix:	mesa_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Calculated collateral coverage ratio.

+ References

No definition available.

+ Details

Name:	mesa_CalculatedCollateralCoverageRatio1
Namespace Prefix:	mesa_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Covenant capping restricted payments.

+ References

No definition available.

+ Details

Name:	mesa_CovenantCappingRestrictedPayments
Namespace Prefix:	mesa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Debt instrument additional amount borrowed.

+ References

No definition available.

+ Details

Name:	mesa_DebtInstrumentAdditionalAmountBorrowed
Namespace Prefix:	mesa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt instrument amount borrowed.

+ References

No definition available.

+ Details

Name:	mesa_DebtInstrumentAmountBorrowed
Namespace Prefix:	mesa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line of credit, revolving commitments.

+ References

No definition available.

+ Details

Name:	mesa_LineOfCreditRevolvingCommitments
Namespace Prefix:	mesa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Minimum collateral coverage ratio covenant.

+ References

No definition available.

+ Details

Name:	mesa_MinimumCollateralCoverageRatioCovenant
Namespace Prefix:	mesa_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Rental coverage ratio.

+ References

No definition available.

+ Details

Name:	mesa_RentalCoverageRatio
Namespace Prefix:	mesa_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Exercise price per share or per unit of warrants or rights outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI https://asc.fasb.org/extlink&oid=126973232&loc=d3e21475-112644

+ Details

Name:	us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.

+ References

+ Details

Name:	us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of reference rate used for variable rate of debt instrument.

+ References

No definition available.

+ Details

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

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=124435984&loc=d3e28551-108399

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI https://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 50
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124429444&loc=SL124452920-239629

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69C
-URI https://asc.fasb.org/extlink&oid=123466577&loc=SL123495737-112612

Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69B
-URI https://asc.fasb.org/extlink&oid=123466577&loc=SL123495735-112612

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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

- Definition

Date when the debt instrument is scheduled to be fully repaid, in YYYY-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 https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 3: 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 https://asc.fasb.org/extlink&oid=126976982&loc=d3e19207-110258

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the 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))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910

+ Details

Name:	us-gaap_LineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of the required periodic payments of both interest and principal.

+ References

+ Details

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

- Definition

Amount, excluding unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
-URI https://asc.fasb.org/extlink&oid=123466204&loc=SL6031897-161870

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69C
-URI https://asc.fasb.org/extlink&oid=123466577&loc=SL123495737-112612

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69B
-URI https://asc.fasb.org/extlink&oid=123466577&loc=SL123495735-112612

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1D
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495340-112611

Reference 7: 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))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_LongTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3255-108585

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(f))
-URI https://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

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

- Definition

Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

+ Details

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

- Details

Name:	us-gaap_AssetsSoldUnderAgreementsToRepurchaseAxis=mesa_TreasuryLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_CreditFacilityAxis=mesa_SpareEngineFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MajorCustomersAxis=mesa_UnitedAirlinesIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_AirTransportationEquipmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorPropertyClassAxis=mesa_PledgedAsCollateralMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Long-Term Debt, Finance Leases, and Other Borrowings - Additional Information (Detail)			1 Months Ended		3 Months Ended
	Dec. 27, 2022 USD ($)	Oct. 30, 2020 USD ($) $ / shares shares	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2022 USD ($)	Sep. 30, 2022 USD ($)	Dec. 31, 2020 USD ($)	Apr. 09, 2020 $ / shares
Debt Instrument [Line Items]
Property and equipment-gross			$ 1,364,700,000		$ 1,364,700,000	$ 1,270,563,000
Long-Term Debt			686,618,000		686,618,000	$ 599,735,000
Revolving loan			$ 25,500,000		$ 25,500,000
Warrants of common stock exercise price \| $ / shares								$ 3.98
Treasury Loan [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Calculated collateral coverage ratio		1.6
Minimum collateral coverage ratio covenant			1.55
Treasury Loan [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Additional collateral coverage ratio		1.6
Loan Agreement [Member]
Debt Instrument [Line Items]
Warrants to purchase shares of common stock \| shares		4,899,497
Warrants of common stock exercise price \| $ / shares		$ 3.98
Spare Engine Facility [Member] \| Loan Agreement [Member]
Debt Instrument [Line Items]
Debt instrument, face amount				$ 35,300,000
Long term debt interest rate description					LIBOR plus 4.24%
Secured term loan facility, maximum borrowing capacity				$ 54,000,000.0
Debt instrument, maturity date				Dec. 31, 2027
Spare Engine Facility [Member] \| LIBOR [Member] \| Loan Agreement [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate				4.24%
United Capacity Purchase Agreement [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate	3.50%
Revolving loan	$ 10,000,000.0
Covenant capping restricted payments	5,000,000.0
Revolving commitments	$ 30,700,000
Rental coverage ratio	1.00
United Capacity Purchase Agreement [Member] \| Revolving Credit Facility [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Amount required					$ 15,000,000.0
United Capacity Purchase Agreement [Member] \| Revolving Credit Facility [Member] \| SOFR [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate	4.50%
United Capacity Purchase Agreement [Member] \| United [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Amount funded by company					25,500,000
Equipment Notes [Member]
Debt Instrument [Line Items]
Long-Term Debt			$ 131,000,000.0		$ 131,000,000.0
Secured Term Loan Facility [Member] \| Loan Agreement [Member]
Debt Instrument [Line Items]
Secured term loan facility, maximum borrowing capacity		$ 200,000,000.0
Debt instrument, maturity date					Oct. 30, 2025
Secured Term Loan Facility [Member] \| Loan Agreement [Member] \| Treasury Loan [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate		3.50%
Secured term loan facility, amount borrowed							$ 195,000,000.0
Secured term loan facility, additional amount borrowed			0		$ 0
Debt instrument, maturity date		Oct. 30, 2025
Aircraft and Equipment [Member] \| Pledged as Collateral [Member]
Debt Instrument [Line Items]
Property and equipment-gross			$ 869,200,000		$ 869,200,000