Segment Information - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 26, 2020	Dec. 28, 2019	Dec. 29, 2018
Revenue from External Customer [Line Items]
Impairment charges	$ 3,771	$ 0	$ 0
Gain on sale of manufacturing equipment	(132)	963	253
Non-cash pension plan termination expense	11,642	0	0
Gain (loss) on sale of assets	0	963	253
Piping Systems [Member]
Revenue from External Customer [Line Items]
Impairment charges	3,800
Gain on sale of real property		1,200	1,400
Gain on sale of manufacturing equipment			700
Operating Segments [Member] \| Piping Systems [Member]
Revenue from External Customer [Line Items]
Impairment charges	3,771
Gain (loss) on sale of assets		1,194	2,093
Operating Segments [Member] \| Industrial Metals [Member]
Revenue from External Customer [Line Items]
Impairment charges	$ 0
Gain (loss) on sale of assets		(275)	1,301
Insurance recovery		$ 500	$ 3,700

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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Amount of gain (loss) on sale or disposal of assets, including but not limited to property plant and equipment, intangible assets and equity in securities of subsidiaries or equity method investee.

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Amount of gain (loss) from sale and disposal of integrated set of activities and assets capable of being conducted and managed for purpose of providing return in form of dividend, lower cost, or other economic benefit to investor, owner, member and participant.

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Amount of expenses for special or contractual termination benefits provided to current employees involuntarily terminated under a benefit arrangement associated exit or disposal activities pursuant to an authorized plan. Excludes expenses related to one-time termination benefits, a discontinued operation or an asset retirement obligation.

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