Revenue (Schedule of Accounts Receivable) (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Sep. 30, 2024	Sep. 30, 2023
Contract With Customer Asset [Line Items]
Total billed receivables	$ 495,659	$ 457,234
Current unbilled receivables (contract assets)	344,399	320,570
Total accounts receivable	840,058	777,804
Less: Allowance for uncollectible amounts	(8,558)	(7,738)	$ (7,738)
Total accounts receivable, net	831,500	770,066
Trade Accounts Receivable [Member]
Contract With Customer Asset [Line Items]
Billed receivables	495,104	455,831
Other (Chinese Financial Institutions) [Member]
Contract With Customer Asset [Line Items]
Billed receivables	$ 555	$ 1,403