Segment Information - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Revenue from External Customer [Line Items]
Gain on sale of manufacturing equipment	$ 963	$ 253	$ 624	[1]
Gain on sale of business	0	0	(1,491)
Impairment charges	0	0	1,466	[1],[2]
Gain (loss) on sale of assets	963	253	1,491	[1],[2]
Insurance recovery	485	3,681	0	[2]
Operating Segments [Member] | Piping Systems [Member]
Revenue from External Customer [Line Items]
Gain on sale of real property	1,200	1,400
Gain on sale of manufacturing equipment		700
Gain on sale of business			(1,491)
Impairment charges			1,466
Gain (loss) on sale of assets	1,194	2,093
Insurance recovery	0	0
Operating Segments [Member] | Industrial Metals [Member]
Revenue from External Customer [Line Items]
Gain on sale of business			0
Impairment charges			$ 0
Gain (loss) on sale of assets	(275)	1,301
Insurance recovery	$ 485	$ (3,681)

[1] The Consolidated Statements of Cash Flows for prior periods have been adjusted to reflect the adoption of ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. The Consolidated Statements of Cash Flows reflect the changes during the periods in the total of cash, cash equivalents, and restricted cash. Therefore, restricted cash activity is included with cash when reconciling the beginning-of-period and end-of-period total amounts shown.

[2] The Consolidated Statement of Income for 2017 has been adjusted to reflect the adoption of ASU 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost in 2018. The components of net periodic benefit cost (income) other than the service cost component are included in other income, net in the Consolidated Statements of Income.