Receivables (Schedule of Receivables) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Dec. 29, 2018	Sep. 29, 2018	Sep. 30, 2018
Receivables [Abstract]
Accounts receivable	$ 233,118	$ 295,180
Long-term contract receivables - Amounts billed	202,000	156,414
Long-term contract receivables - Unbilled recoverable costs and accrued profits	420,093	316,489	$ 405,610
Total long-term contract receivables	622,093	472,903
Other	17,055	30,787
Less allowance for doubtful accounts	(4,851)	(4,959)
Receivables	$ 867,415	$ 793,911	$ 883,032

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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Amounts due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer) for goods or services (including trade receivables) that have been delivered or sold in the normal course of business.

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

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Amount of expense related to write-down of receivables to the amount expected to be collected. Includes, but is not limited to, accounts receivable and notes 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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