Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk - Notional Values For Derivatives Instrument (Details) - Designated as Hedging Instrument £ in Millions, zł in Millions, $ in Millions |
Mar. 31, 2025
USD ($)
|
Mar. 31, 2025
PLN (zł)
|
Mar. 31, 2025
GBP (£)
|
Sep. 30, 2024
USD ($)
|
Sep. 30, 2024
PLN (zł)
|
Sep. 30, 2024
GBP (£)
|
|---|---|---|---|---|---|---|
| Interest rate contracts | ||||||
| Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items] | ||||||
| Derivative, notional amount | $ 0.0 | $ 500.0 | ||||
| Foreign currency forward contracts | Polish Zloty | ||||||
| Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items] | ||||||
| Derivative, notional amount | 51.1 | zł 210.0 | 37.5 | zł 156.1 | ||
| Foreign currency forward contracts | British Pound Sterling | ||||||
| Security Owned and Sold, Not yet Purchased, at Fair Value [Line Items] | ||||||
| Derivative, notional amount | $ 153.3 | £ 124.0 | $ 88.8 | £ 72.0 |