Revenue (Schedule of Accounts Receivable) (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Contract With Customer Asset [Line Items]
Total billed receivables	$ 485,227	$ 368,769
Current unbilled receivables (contract assets)	270,479	245,117
Total accounts receivable	755,706	613,886
Less: Allowance for uncollectible amounts	(5,847)	(3,922)
Total accounts receivable, net	749,859	609,964
Trade Accounts Receivable [Member]
Contract With Customer Asset [Line Items]
Billed receivables	434,287	359,364
Other (Chinese Financial Institutions) [Member]
Contract With Customer Asset [Line Items]
Billed receivables	$ 50,940	$ 9,405