Investments - Schedule of Contract Maturity of Available for Sale (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Sep. 30, 2024
Investments, Debt and Equity Securities [Abstract]
Within one year	$ 224,571	$ 578,276
After one to two years	450,889	0
After two to three years	95,119	0
Total	$ 770,579	$ 578,276

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

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+ Details