Debt - Schedule of debt (Details) - USD ($)	6 Months Ended
Mar. 30, 2019	Sep. 29, 2018
Debt Disclosure [Abstract]
Debt, interest rate, stated percentage	5.125%	4.81%
Debt	$ 40,000,000	$ 40,000,000
Unamortized debt issuance costs	(199,000)	(236,000)
Total indebtedness	39,801,000	39,764,000
Less short-term portion	(10,000,000)	(6,667,000)
Long-term debt	$ 29,801,000	$ 33,097,000
LIBOR
Debt Instrument [Line Items]
Debt, basis spread on variable rate	2.25%

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of unamortized debt discount (premium) and debt issuance costs.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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