Revenue (Schedule of Accounts Receivable) (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Sep. 30, 2023
Contract With Customer Asset [Line Items]
Total billed receivables	$ 457,234	$ 485,227
Current unbilled receivables (contract assets)	320,570	270,479
Total accounts receivable	777,804	755,706
Less: Allowance for uncollectible amounts	(7,738)	(5,847)
Total accounts receivable, net	770,066	749,859
Trade Accounts Receivable [Member]
Contract With Customer Asset [Line Items]
Billed receivables	455,831	434,287
Other (Chinese Financial Institutions) [Member]
Contract With Customer Asset [Line Items]
Billed receivables	$ 1,403	$ 50,940