Receivables (Schedule of Receivables) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Dec. 28, 2019	Sep. 28, 2019
Receivables [Abstract]
Accounts receivable	$ 243,988	$ 255,079
Over-time contract receivables - Billed	241,740	222,075
Over-time contract receivables - Unbilled	497,356	468,824
Total over-time contract receivables	739,096	690,899
Other	11,041	16,711
Less allowance for doubtful accounts	(4,911)	(5,402)
Receivables	$ 989,214	$ 957,287

Amount billed to customers under long-term contracts or programs but not paid. Excludes amounts due that have been withheld because of retainage provisions in a contract.

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Amount, before allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.

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Amount due from parties in nontrade transactions, classified as other.

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Amount of expense (reversal of expense) for expected credit loss on accounts receivable.

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Amount to be collected within one year of the balance sheet date (or one operating cycle, if longer) from customers in accordance with the contractual provisions of long-term contracts or programs including amounts billed and unbilled as of the balance sheet date.

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The total amount due to the entity within one year of the balance sheet date (or one operating cycle, if longer) from outside sources, including trade accounts receivable, notes and loans receivable, as well as any other types of receivables, net of allowances established for the purpose of reducing such receivables to an amount that approximates their net realizable value.

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Unbilled amounts due for services rendered or to be rendered, actions taken or to be taken, or a promise to refrain from taking certain actions in accordance with the terms of a legally binding agreement between the entity and, at a minimum, one other party. An example would be amounts associated with contracts or programs where the recognized revenue for performance thereunder exceeds the amounts billed under the terms thereof as of the date of the balance sheet.

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