Short-Term Borrowings and Long-Term Debt - Schedule of Long-Term Debt (Parenthetical) (Detail) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
Mar. 31, 2026	Sep. 30, 2025
Mortgage Facility [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	2.20%
Mortgage Facility [Member] \| Mortgage Facility Payable to Flagship Bank [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	5.75%	5.75%
Debt instrument basis percentage	1.00%	1.00%
Principal and interest payments with a balloon payment	$ 4.0	$ 4.0
Additional extension for two one-year periods	Aug. 31, 2027	Aug. 31, 2027
Mortgage Facility [Member] \| Mortgage Facility Payable to Flagship Bank [Member] \| Interest Rate Prime [Member]
Debt Instrument [Line Items]
Debt instrument description of variable rate basis	(prime minus 100 basis points with a floor of 2.00	(prime minus 100 basis points with a floor of 2.00
Mortgage Facility [Member] \| Mortgage Facility Payable to Flagship Bank [Member] \| Interest Rate Floor [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	2.00%	2.00%
Mortgage Facility [Member] \| Mortgage Facility Payable to Seacoast National Bank [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	5.92%	5.92%
Principal and interest payments with a balloon payment	$ 10.0	$ 10.0
Additional extension for two one-year periods	Sep. 30, 2031	Sep. 30, 2031
Mortgage Facility [Member] \| Mortgage Facility Payable to Seacoast National Bank [Member] \| SOFR [Member]
Debt Instrument [Line Items]
Debt instrument basis percentage	2.20%	2.20%
Debt instrument description of variable rate basis	(SOFR plus 220 basis points	(SOFR plus 220 basis points
Mortgage Facility [Member] \| Mortgage facility payable to Hancock Whitney Bank [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	6.13%	6.13%
Debt instrument basis percentage	0.625%	0.625%
Principal and interest payments with a balloon payment	$ 15.5	$ 15.5
Additional extension for two one-year periods	Nov. 30, 2027	Nov. 30, 2027
Percentage of outstanding borrowings hedged	50.00%	50.00%
Fixed interest rate	3.20%	3.20%
Mortgage Facility [Member] \| Mortgage facility payable to Hancock Whitney Bank [Member] \| Interest Rate Prime [Member]
Debt Instrument [Line Items]
Debt instrument description of variable rate basis	(prime minus 62.5 basis points with a floor of 2.25	(prime minus 62.5 basis points with a floor of 2.25
Mortgage Facility [Member] \| Mortgage facility payable to Hancock Whitney Bank [Member] \| Interest Rate Floor [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	2.25%	2.25%
Mortgage Facility [Member] \| Mortgage Facility Payable To M&T Bank [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	5.87%	5.87%
Additional extension for two one-year periods	Oct. 31, 2027	Oct. 31, 2027
Mortgage Facility [Member] \| Mortgage Facility Payable To M&T Bank [Member] \| SOFR [Member]
Debt Instrument [Line Items]
Debt instrument description of variable rate basis	(SOFR plus 220 basis points	(SOFR plus 220 basis points
Mortgage Facility [Member] \| Revolving mortgage facility with FineMark National Bank & Trust [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	220.00%	220.00%
Term Loan [Member] \| Term loan payable to M&T Bank [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	5.42%	5.42%
Additional extension for two one-year periods	Aug. 31, 2027	Aug. 31, 2027
Term Loan [Member] \| Loan payable to TRANSPORT S.a.s di Taula Vittorio and C. [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	5.53%	5.53%
Additional extension for two one-year periods	Dec. 31, 2030	Dec. 31, 2030

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

No definition available.

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- Definition

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

+ References

No definition available.

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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- Definition

Date when the debt instrument is scheduled to be fully repaid, in YYYY-MM-DD format.

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- Definition

Amount of payment greater than the preceding installment payments to be paid at final maturity date of debt.

+ References

No definition available.

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- Definition

Fixed interest rate related to the interest rate derivative.

+ References

No definition available.

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Percentage of an entity's outstanding debt that is designated as a hedged item in cash flow, fair value, or net investment hedge.

+ References

No definition available.

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