Short-Term Borrowings and Long-Term Debt - Schedule of Long-Term Debt (Parenthetical) (Detail) - Mortgage Facility [Member] $ in Millions	9 Months Ended
Jun. 30, 2021 USD ($)
Mortgage Facility Payable to Flagship Bank [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	2.25%
Debt instrument basis percentage	1.00%
Principal and interest payments with a balloon payment	$ 4.0
Additional extension for two one-year periods	Aug. 31, 2027
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%
Mortgage Facility Payable to Flagship Bank [Member] \| Interest Rate Floor [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	2.00%
Mortgage Facility Payable to Seacoast National Bank [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	3.00%
Debt instrument basis percentage	0.625%
Principal and interest payments with a balloon payment	$ 6.0
Additional extension for two one-year periods	Sep. 30, 2031
Mortgage Facility Payable to Seacoast National Bank [Member] \| Interest Rate Prime [Member]
Debt Instrument [Line Items]
Debt instrument description of variable rate basis	greater of 3.00% or prime minus 62.5 basis points
Mortgage facility payable to Hancock Whitney Bank [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	2.63%
Debt instrument basis percentage	0.625%
Principal and interest payments with a balloon payment	$ 15.5
Additional extension for two one-year periods	Nov. 30, 2027
Percentage of outstanding borrowings hedged	50.00%
Fixed interest rate	3.20%
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%
Mortgage facility payable to Hancock Whitney Bank [Member] \| Interest Rate Floor [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	2.25%
Revolving mortgage facility with FineMark National Bank & Trust [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	3.00%
Debt instrument basis percentage	0.25%
Additional extension for two one-year periods	Sep. 30, 2027
Current available borrowings	$ 26.1
Revolving mortgage facility with FineMark National Bank & Trust [Member] \| Interest Rate Base [Member]
Debt Instrument [Line Items]
Debt instrument description of variable rate basis	base minus 25 basis points with a floor of 3.00%
Revolving mortgage facility with FineMark National Bank & Trust [Member] \| Interest Rate Floor [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	3.00%

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

No definition available.

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- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

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- Definition

Contractual interest rate for funds borrowed, under the debt 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(a)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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- 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

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- Definition

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

Reference 2: 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 http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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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.

+ Details

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- Definition

Fixed interest rate related to the interest rate derivative.

+ References

No definition available.

+ Details

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- Definition

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

+ 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 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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- Definition

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.

+ Details

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