Additional collateral coverage ratio.

No definition available.

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Period Type:	duration

- Definition

Calculated collateral coverage ratio.

+ References

No definition available.

+ Details

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- Definition

Covenant capping restricted payments.

+ References

No definition available.

+ Details

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Balance Type:	credit
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- Definition

Debt instrument additional amount borrowed.

+ References

No definition available.

+ Details

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- Definition

Debt instrument amount borrowed.

+ References

No definition available.

+ Details

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Balance Type:	credit
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- Definition

Fee waiver granted on minimum liquidity requirement.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Line of credit facility collateralized by spare parts.

+ References

No definition available.

+ Details

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

- Definition

Line of credit, revolving commitments.

+ References

No definition available.

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Minimum collateral coverage ratio covenant.

+ References

No definition available.

+ Details

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- Definition

Minimum liquidity requirement of cash and cash equivalents.

+ References

No definition available.

+ Details

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- Definition

Percentage of controllable completion factor.

+ References

No definition available.

+ Details

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Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Rental coverage ratio.

+ References

No definition available.

+ Details

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Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

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

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-Section 50
-Paragraph 3
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Period Type:	instant

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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

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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

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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.

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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.

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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

+ Details

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

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

Amount of decrease in line of credit facility from forgiveness by the holder of the line of credit.

+ References

No definition available.

+ Details

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

- Definition

Fair value of the amount outstanding under the credit facility.

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Balance Type:	credit
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- 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

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- Definition

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

+ References

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- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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- Definition

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

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- Definition

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt classified as current. Excludes lease obligation.

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- 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.

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- 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.

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- Definition

Amount of realized gain (loss) on investment.

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Long-Term Debt, Finance Leases, and Other Borrowings - Additional Information (Detail)							3 Months Ended		5 Months Ended	9 Months Ended
	Nov. 23, 2024	Jul. 01, 2024 USD ($)	Jan. 11, 2024 USD ($)	Sep. 06, 2023 USD ($)	Dec. 27, 2022 USD ($)	Oct. 30, 2020 USD ($) $ / shares shares	Jun. 30, 2024 USD ($) $ / shares	Mar. 31, 2024 USD ($)	Nov. 22, 2024	Jun. 30, 2024 USD ($) $ / shares	Jun. 30, 2023 USD ($)	Sep. 30, 2024 USD ($)	Jul. 16, 2024 USD ($)	Sep. 30, 2023 USD ($)	Dec. 31, 2020 USD ($)
Debt Instrument [Line Items]
Property and equipment-gross							$ 760,337,000			$ 760,337,000				$ 1,049,203,000
Long-Term Debt							360,518,000			360,518,000				528,278,000
Current portion of long-term debt							72,769,000			72,769,000				$ 163,550,000
Gain on investments							$ (776,000)			$ 6,454,000
Warrants of common stock exercise price \| $ / shares							$ 3.98			$ 3.98
Treasury Loan [Member] \| Forecast [Member]
Debt Instrument [Line Items]
Minimum collateral coverage ratio covenant	1.55								1.44
Treasury Loan [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Calculated collateral coverage ratio						1.55
Treasury Loan [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Additional collateral coverage ratio						1.55
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
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Repayments of long term debt			$ 2,100,000
Permitted amount to redraw from existing credit facility				$ 7,900,000
Revolving Credit Facility [Member] \| Subsequent Event [Member]
Debt Instrument [Line Items]
Line of credit available to draw												$ 13,200,000
Line of credit facility collateralized by spare parts												$ 12,400,000
Revolving Credit Facility [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Revolving commitments				50,700,000
Revolving Credit Facility [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Revolving commitments				$ 30,700,000
United Capacity Purchase Agreement [Member]
Debt Instrument [Line Items]
Repayments of long term debt			10,500,000
Gain on investments			$ 7,200,000
United Capacity Purchase Agreement [Member] \| Subsequent Event [Member]
Debt Instrument [Line Items]
Minimum liquidity requirement of cash and cash equivalents													$ 15,000,000
United Capacity Purchase Agreement [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long term debt, basis spread on variable rate				3.50%	3.50%
Revolving loan					$ 10,500,000
Covenant capping restricted payments					5,000,000
Repayments of lines of credit							$ 10,500,000
Revolving commitments					$ 30,700,000
Rental coverage ratio					1
United Capacity Purchase Agreement [Member] \| Revolving Credit Facility [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Amount required											$ 15,000,000
United Capacity Purchase Agreement [Member] \| Revolving Credit Facility [Member] \| Minimum [Member] \| Subsequent Event [Member]
Debt Instrument [Line Items]
Fee waiver granted on minimum liquidity requirement		$ 15,000,000
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%	4.50%
United Capacity Purchase Agreement [Member] \| United [Member]
Debt Instrument [Line Items]
Percentage of controllable completion factor										99.30%
United Capacity Purchase Agreement [Member] \| United [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Deemed prepayment, outstanding							4,500,000			$ 4,500,000
Amount funded by company											$ 25,500,000
Additional prepayment with potential forgiveness								$ 15,000,000		15,000,000
Equipment Notes [Member]
Debt Instrument [Line Items]
Long-Term Debt							97,300,000			$ 97,300,000
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							$ 507,000,000			$ 507,000,000