Restructuring Charges - Restructuring Reserves (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Dec. 27, 2019	Dec. 28, 2018	Sep. 30, 2018
Restructuring Reserve [Roll Forward]
Beginning balance	$ 537	$ 551
Charges	220		$ 3,804
Utilization	(342)		(3,818)
Exchange rate effects	14
Ending balance	429		551
One-time Termination Benefits
Restructuring Reserve [Roll Forward]
Charges	12	285
Facility Closing
Restructuring Reserve [Roll Forward]
Charges	208	1,080
Operating Segments \| Electrical Raceway \| Severance
Restructuring Reserve [Roll Forward]
Beginning balance	392	212
Charges	12		1,047
Utilization	(26)		(867)
Exchange rate effects	14
Ending balance	392		212
Operating Segments \| Electrical Raceway \| Other
Restructuring Reserve [Roll Forward]
Beginning balance	0	310
Charges	208		2,544
Utilization	(208)		(2,854)
Exchange rate effects	0
Ending balance	0		310
Operating Segments \| MP&S \| Severance
Restructuring Reserve [Roll Forward]
Beginning balance	145	0
Charges	0		213
Utilization	(108)		(68)
Exchange rate effects	0
Ending balance	37		0
Operating Segments \| MP&S \| Other
Restructuring Reserve [Roll Forward]
Beginning balance	0	$ 29
Charges	0		0
Utilization	0		(29)
Exchange rate effects	0
Ending balance	$ 0		$ 29

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of foreign currency translation gain (loss) which decreases (increases) the restructuring reserve.

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