Borrowings - 2028 Notes (Narrative) (Details) - USD ($) $ in Thousands	Dec. 05, 2023	Jun. 30, 2024	Apr. 11, 2024	Sep. 30, 2023
Debt Instrument [Line Items]
Long-term debt		$ 4,315,465		$ 3,117,719
2028 Notes
Debt Instrument [Line Items]
Debt instrument, face amount	$ 450,000
Long-term debt		$ 450,000
Interest rate	7.05%
Debt instrument, redemption price, percentage	100.00%
2028 Notes | Interest rate swaps
Debt Instrument [Line Items]
Fixed interest rate (as a percent)	7.31%		7.31%
Notional amount	$ 225,000		$ 225,000
2028 Notes | US Treasury (UST) Interest Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.45%
2028 Notes | One-month Secured Overnight Financing Rate (SOFR) | Interest rate swaps
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	3.327%		2.835%