Debt instrument, spread adjustment.

No definition available.

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Namespace Prefix:	extr_
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Balance Type:	na
Period Type:	duration

- Definition

Debt instrument, subject to floor.

+ References

No definition available.

+ Details

Name:	extr_DebtInstrumentSubjectToFloor
Namespace Prefix:	extr_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of credit additional incremental loan facility.

+ References

No definition available.

+ Details

Name:	extr_LineOfCreditAdditionalIncrementalLoanFacility
Namespace Prefix:	extr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of amortization expense attributable to debt issuance costs.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(8))
-Publisher FASB
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Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
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-Name Accounting Standards Codification
-Section 45
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-28

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 835
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-Name Accounting Standards Codification
-Section 45
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482925/835-30-45-3

+ Details

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

- 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

Incremental percentage increase (decrease) in the stated rate on a debt instrument.

+ References

No definition available.

+ Details

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

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 944
-SubTopic 605
-Name Accounting Standards Codification
-Section 55
-Paragraph 15
-Publisher FASB
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-URI https://asc.fasb.org/1943274/2147477548/944-605-55-12

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(b))
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-Publisher FASB
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+ Details

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

- Definition

Period remaining on line of credit facility before it terminates, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityExpirationPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
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

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
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-Topic 235
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-Section S99
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-Topic 470
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-Name Accounting Standards Codification
-Section 50
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481544/470-10-50-6

+ Details

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

- 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

The cash inflow from a contractual arrangement with the lender, including letter of credit, standby letter of credit and revolving credit arrangements, under which borrowings can be made up to a specific amount at any point in time with maturities due beyond one year or the operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-14

+ Details

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

- Definition

Amount of cash outflow for payment of an obligation from a lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480738/235-10-S50-1

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-Paragraph 15
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-15

+ Details

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

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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Balance Type:
Period Type:

- Details

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Period Type:

- Details

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- Details

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- Details

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Debt (Narratives) (Details) - USD ($)		3 Months Ended
Debt (Narratives) (Details) - USD ($)	Jun. 22, 2023	Sep. 30, 2025	Sep. 30, 2024
Line Of Credit Facility [Line Items]
Borrowings under revolving facility		$ 25,000,000
Outstanding letters of credit		$ 14,200,000
Credit Agreement \| Applicable Margin for SOFR
Line Of Credit Facility [Line Items]
Debt instrument, subject to floor	0.00%
Debt instrument, spread adjustment	0.10%
Credit Agreement \| Term Loan
Line Of Credit Facility [Line Items]
Borrowing capacity from Credit Agreement	$ 200,000,000
Credit Agreement \| Revolving Facility
Line Of Credit Facility [Line Items]
Credit Facility, term	5 years
Borrowing capacity from Credit Agreement	$ 150,000,000
Amended Credit Agreement
Line Of Credit Facility [Line Items]
Debt instrument interest rate		6.54%	7.52%
Amended Credit Agreement \| Interest Expense
Line Of Credit Facility [Line Items]
Amortization of deferred financing costs		$ 300,000	$ 300,000
Amended Credit Agreement \| Term Loan
Line Of Credit Facility [Line Items]
Payments of lines of credit		0	$ 0
Amended Credit Agreement \| Revolving Facility
Line Of Credit Facility [Line Items]
Borrowings under revolving facility		25,000,000
Borrowing capacity from Credit Agreement		$ 110,800,000
Maximum \| Credit Agreement
Line Of Credit Facility [Line Items]
Additional incremental loan facility	$ 100,000,000
Maximum \| Credit Agreement \| Applicable Margin for Base Rate
Line Of Credit Facility [Line Items]
Borrowings, interest rate	1.75%
Maximum \| Credit Agreement \| Applicable Margin for SOFR
Line Of Credit Facility [Line Items]
Borrowings, interest rate	2.75%
Minimum \| Credit Agreement \| Applicable Margin for Base Rate
Line Of Credit Facility [Line Items]
Borrowings, interest rate	1.00%
Minimum \| Credit Agreement \| Applicable Margin for SOFR
Line Of Credit Facility [Line Items]
Borrowings, interest rate	2.00%