Note 11 - Supplementary Balance Sheet Information - Allowance for Credit Losses on Accounts Receivables (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Balance	$ 8,057	$ 5,162	$ 4,318
Provisions	7,250	8,849	3,536
Payments received	(7,455)	(5,884)	(2,278)
Write-offs and adjustments	(1,294)	(70)	(414)
Balance	$ 6,558	$ 8,057	$ 5,162

Amount of allowance for credit loss on accounts receivable.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Namespace Prefix:	us-gaap_
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Balance Type:	credit
Period Type:	instant

- Definition

Amount of increase in allowance for credit loss on accounts receivable, from recovery.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
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- Definition

Amount of direct write-downs of accounts receivable charged against the allowance.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
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- Definition

Amount of expense (reversal of expense) for expected credit loss on accounts receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
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-Topic 220
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