Borrowings - 2027 Notes - Narrative (Details) - USD ($) $ in Thousands	Aug. 03, 2021	Mar. 31, 2026	Sep. 30, 2025
Debt Instrument [Line Items]
Long-term debt		$ 4,702,478	$ 4,900,773
2027 Notes
Debt Instrument [Line Items]
Debt instrument, face amount	$ 350,000
Long-term debt		$ 350,000	$ 350,000
Interest rate	2.05%
Debt instrument, redemption price, percent	100.00%
Debt instrument, basis spread on variable rate	0.25%