Revenue (Schedule of Accounts Receivable) (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021
Contract With Customer Asset [Line Items]
Total billed receivables	$ 368,769	$ 322,119
Current unbilled receivables (contract assets)	245,117	204,596
Total accounts receivable	613,886	526,715
Less: Allowance for uncollectible amounts	(3,922)	(3,664)
Total accounts receivable, net	609,964	523,051
Trade Accounts Receivable [Member]
Contract With Customer Asset [Line Items]
Billed receivables	359,364	298,951
Other (Chinese Financial Institutions) [Member]
Contract With Customer Asset [Line Items]
Billed receivables	$ 9,405	$ 23,168