Note 9 - Stockholders' Equity - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Balance	$ 1,768,967	$ 2,534,500
Balance	1,701,492	2,222,871
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Balance	(34,170)	(88,448)
Other comprehensive income (loss) before reclassifications	(23,860)	25,725
Amounts reclassified from accumulated other comprehensive loss	0	0
Balance	(58,030)	(62,723)
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Parent [Member]
Balance	(263)	(5,135)
Other comprehensive income (loss) before reclassifications	363	3,276
Amounts reclassified from accumulated other comprehensive loss	0	0
Balance	100	(1,859)
AOCI, Derivative Qualifying as Hedge, Excluded Component, Parent [Member]
Balance	21,468	31,487
Other comprehensive income (loss) before reclassifications	(5,088)	(8,288)
Amounts reclassified from accumulated other comprehensive loss	0	0
Balance	16,380	23,199
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Balance	(499)	(330)
Other comprehensive income (loss) before reclassifications	(136)	(61)
Amounts reclassified from accumulated other comprehensive loss	36	46
Balance	(599)	(345)
AOCI Attributable to Parent [Member]
Balance	(13,464)	(62,426)
Other comprehensive income (loss) before reclassifications	(28,721)	20,652
Amounts reclassified from accumulated other comprehensive loss	36	46
Balance	$ (42,149)	$ (41,728)