Segment Information - Summary of Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Summary of segment information [Abstract]
Net sales	$ 640,060	$ 577,920	[1]
Cost of goods sold	545,670	488,427	[1]
Depreciation and amortization	9,456	8,355	[1]
Selling, general, and administrative expense	34,057	35,574	[1]
Asset impairment	3,469	0	[2]
Operating income	47,408	45,564	[1]
Interest expense	(5,909)	(2,531)	[1]
Other income, net	560	594	[1]
Income before income taxes	42,059	43,627	[1]
Operating Segments [Member] | Piping Systems [Member]
Summary of segment information [Abstract]
Net sales	430,964	398,775
Cost of goods sold	372,895	344,646
Depreciation and amortization	5,878	5,342
Selling, general, and administrative expense	19,242	18,197
Asset impairment	0
Operating income	32,949	30,590
Operating Segments [Member] | Industrial Metals [Member]
Summary of segment information [Abstract]
Net sales	177,332	149,837
Cost of goods sold	149,423	124,043
Depreciation and amortization	1,903	1,898
Selling, general, and administrative expense	3,373	3,549
Asset impairment	0
Operating income	22,633	20,347
Operating Segments [Member] | Climate [Member]
Summary of segment information [Abstract]
Net sales	36,063	34,279
Cost of goods sold	27,286	25,564
Depreciation and amortization	621	629
Selling, general, and administrative expense	2,609	2,476
Asset impairment	0
Operating income	5,547	5,610
Corporate and Eliminations [Member]
Summary of segment information [Abstract]
Net sales	(4,299)	(4,971)
Cost of goods sold	(3,934)	(5,826)
Depreciation and amortization	1,054	486
Selling, general, and administrative expense	8,833	11,352
Asset impairment	3,469
Operating income	$ (13,721)	$ (10,983)

[1] The Condensed Consolidated Statement of Income for the quarter ended April 1, 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. The components of net periodic benefit cost (income) other than the service cost component are included in other income, net in the Condensed Consolidated Statements of Income. Refer to Note 1 for further discussion.

[2] The Condensed Consolidated Statement of Cash Flows for the quarter ended April 1, 2017 has been adjusted to reflect the adoption of ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. The Condensed Consolidated Statements of Cash Flows reflects 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. Refer to Note 1 for further discussion.