Revenue (Schedule of Accounts Receivable) (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Sep. 30, 2022
Contract With Customer Asset [Line Items]
Total billed receivables	$ 446,699	$ 368,769
Current unbilled receivables (contract assets)	294,806	245,117
Total accounts receivable	741,505	613,886
Less: Allowance for uncollectible amounts	(8,700)	(3,922)
Total accounts receivable, net	732,805	609,964
Trade Accounts Receivable [Member]
Contract With Customer Asset [Line Items]
Billed receivables	408,601	359,364
Other (Chinese Financial Institutions) [Member]
Contract With Customer Asset [Line Items]
Billed receivables	$ 38,098	$ 9,405