Note 12 - Fair Value Measurements (Details Textual) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Jun. 30, 2024	Jun. 30, 2024	Jun. 30, 2023	Sep. 30, 2023
Payments to Acquire Debt Securities, Available-for-Sale		$ 378,275	$ 236,194
Debt Securities, Available-for-Sale, Current	$ 259,296	259,296		$ 338,873
Convertible Debt Securities [Member] \| Private Company [Member]
Payments to Acquire Debt Securities, Available-for-Sale	2,000
Debt Securities, Available-for-Sale, Current	$ 2,000	$ 2,000

Amount of cash outflow to acquire investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 11
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481830/320-10-45-11

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-13

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 11
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-11

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