Investments - Schedule of Contract Maturity of Available for Sale (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Sep. 30, 2024
Investments, Debt and Equity Securities [Abstract]
Within one year	$ 422,082	$ 578,276
After one to two years	301,085	0
After two to three years	188,533	0
Available-for-sale securities	$ 911,700	$ 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