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Investments & Fair Value Measurements - AFS Maturities (Details) - USD ($) $ in Thousands | Mar. 31, 2023 | Sep. 30, 2022
--- | --- | ---
Amortized Cost |  |
Due within 1 year | $ 218,820 | $ 336,291
Due in 1 to 2 years | 59,149 | 53,721
Due in 2 to 5 years | 33,090 | 42,122
Total | 311,059 | 432,134
Fair Value |  |
Due within 1 year | 217,487 | 334,537
Due in 1 to 2 years | 57,449 | 51,332
Due in 2 to 5 years | 33,127 | 40,280
Debt Securities, Available-for-sale | $ 308,063 | $ 426,149

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