Derivatives and Hedging Activity - Designated and Non-Designated Hedges (Details) € in Thousands, £ in Thousands, SFr in Thousands, $ in Thousands, $ in Thousands	Sep. 30, 2023 EUR (€) contract	Sep. 30, 2023 GBP (£) contract	Sep. 30, 2023 AUD ($) contract	Sep. 30, 2023 CHF (SFr) contract	Sep. 30, 2023 USD ($) contract
Derivatives
Number of Contracts	683	683	683	683	683
Foreign exchange contracts | EUR | Long
Derivatives
Number of Contracts	11	11	11	11	11
Aggregate Notional Amount | €	€ 45,627
Foreign exchange contracts | EUR | Short
Derivatives
Number of Contracts	194	194	194	194	194
Aggregate Notional Amount | €	€ 824,687
Foreign exchange contracts | GBP | Long
Derivatives
Number of Contracts	18	18	18	18	18
Aggregate Notional Amount | £		£ 122,142
Foreign exchange contracts | GBP | Short
Derivatives
Number of Contracts	205	205	205	205	205
Aggregate Notional Amount | £		£ 648,549
Foreign exchange contracts | AUD | Long
Derivatives
Number of Contracts	5	5	5	5	5
Aggregate Notional Amount | $			$ 379,571
Foreign exchange contracts | AUD | Short
Derivatives
Number of Contracts	110	110	110	110	110
Aggregate Notional Amount | $			$ 1,070,581
Foreign exchange contracts | CHF | Short
Derivatives
Number of Contracts	73	73	73	73	73
Aggregate Notional Amount | SFr				SFr 20,891
Interest rate swaps – Paying fixed rates | USD
Derivatives
Number of Contracts	56	56	56	56	56
Aggregate Notional Amount | $					$ 4,385,516
Interest rate swaps – Receiving fixed rates | USD
Derivatives
Number of Contracts	2	2	2	2	2
Aggregate Notional Amount | $					$ 970,000
Interest rate caps | GBP
Derivatives
Number of Contracts	1	1	1	1	1
Aggregate Notional Amount | £		£ 61,000
Interest rate caps | USD
Derivatives
Number of Contracts	4	4	4	4	4
Aggregate Notional Amount | $					$ 624,666
Credit instruments | USD
Derivatives
Number of Contracts	3	3	3	3	3
Aggregate Notional Amount | $					$ 49,000
Interest rate swap guarantees | USD
Derivatives
Number of Contracts	1	1	1	1	1
Aggregate Notional Amount | $					$ 102,331