Fair Value Measurements - Financial Assets Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Sep. 30, 2024
Assets:
Fair Value	$ 134,136	$ 150,667
Marketable securities	54,625	45,289
Cash deposits	134,100	142,800
Fair Value, Measurements, Recurring
Assets:
Fair Value	6	7,899
Marketable securities	54,625	45,289
Total	54,631	53,188
Fair Value, Measurements, Recurring | Active Markets for Identical Instruments (Level 1)
Assets:
Fair Value	6	7,899
Marketable securities	54,625	45,289
Total	$ 54,631	$ 53,188