Segment Information - Summary of Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
Summary of segment information [Abstract]
Net sales	$ 666,394	$ 662,773	$ 1,278,175	$ 1,302,833
Cost of goods sold	563,948	563,820	1,075,341	1,109,490
Depreciation and amortization	10,478	9,006	21,033	18,462
Selling, general, and administrative expense	40,446	38,428	81,099	72,485
(Gain) loss on sale of assets	0	(409)	0	3,060
Operating income	51,522	51,928	100,702	99,336
Interest expense	(7,033)	(6,073)	(13,987)	(11,982)
Other income (expense), net	462	586	290	1,146
Income before income taxes	44,951	46,441	87,005	88,500
Operating Segments [Member]
Summary of segment information [Abstract]
Net sales	669,665	668,246	1,286,866	1,312,605
Operating Segments [Member] | Piping Systems [Member]
Summary of segment information [Abstract]
Net sales	425,865	453,183	802,357	884,147
Cost of goods sold	364,332	384,821	689,128	757,716
Depreciation and amortization	5,652	5,744	11,202	11,622
Selling, general, and administrative expense	19,985	20,599	37,882	39,841
(Gain) loss on sale of assets		0		0
Operating income	35,896	42,019	64,145	74,968
Operating Segments [Member] | Industrial Metals [Member]
Summary of segment information [Abstract]
Net sales	147,719	175,891	298,594	353,223
Cost of goods sold	127,950	154,401	254,649	303,824
Depreciation and amortization	1,838	1,948	3,682	3,851
Selling, general, and administrative expense	3,020	3,449	6,165	6,822
(Gain) loss on sale of assets		0		0
Operating income	14,911	16,093	34,098	38,726
Operating Segments [Member] | Climate [Member]
Summary of segment information [Abstract]
Net sales	96,081	39,172	185,915	75,235
Cost of goods sold	74,849	30,688	141,678	57,974
Depreciation and amortization	2,128	627	4,441	1,248
Selling, general, and administrative expense	6,069	2,510	14,375	5,119
(Gain) loss on sale of assets		0		0
Operating income	13,035	5,347	25,421	10,894
Corporate and Eliminations [Member]
Summary of segment information [Abstract]
Net sales	(3,271)	(5,473)	(8,691)	(9,772)
Cost of goods sold	(3,183)	(6,090)	(10,114)	(10,024)
Depreciation and amortization	860	687	1,708	1,741
Selling, general, and administrative expense	11,372	11,870	22,677	20,703
(Gain) loss on sale of assets		(409)		3,060
Operating income	$ (12,320)	$ (11,531)	$ (22,962)	$ (25,252)