Borrowings - 2026 Notes (Narrative) (Details) - USD ($) $ in Thousands	Feb. 24, 2021	Jun. 30, 2024	Sep. 30, 2023	Oct. 13, 2021
Debt Instrument [Line Items]
Long-term debt		$ 4,315,465	$ 3,117,719
2026 Notes
Debt Instrument [Line Items]
Debt instrument, face amount	$ 400,000			$ 200,000
Long-term debt		$ 600,000	$ 600,000
Interest rate	2.50%
Debt instrument, redemption price, percentage	100.00%
2026 Notes | US Treasury (UST) Interest Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.30%