Segment Information - Summary of Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 28, 2019	Sep. 29, 2018
Summary of segment information [Abstract]
Net sales	$ 608,602	$ 645,958	$ 1,886,777	$ 1,948,791
Cost of goods sold	510,788	566,956	1,586,129	1,676,446
Depreciation and amortization	10,823	10,619	31,856	29,081
Selling, general, and administrative expense	40,739	38,889	121,838	112,077
Gain on sale of assets	0	(2,691)	0	(334)
Insurance recovery	0	(1,486)	0	(1,486)
Operating income	46,252	33,671	146,954	133,007
Interest expense	(6,148)	(6,746)	(20,135)	(18,728)
Other income (expense), net	533	411	823	1,557
Income before income taxes	40,637	27,336	127,642	115,836
Operating Segments [Member]
Summary of segment information [Abstract]
Net sales	617,298	650,853	1,904,164	1,963,458
Operating Segments [Member] | Piping Systems [Member]
Summary of segment information [Abstract]
Net sales	390,917	410,525	1,193,274	1,294,672
Cost of goods sold	330,418	363,174	1,019,546	1,120,890
Depreciation and amortization	5,751	5,946	16,953	17,568
Selling, general, and administrative expense	18,738	17,387	56,620	57,931
Gain on sale of assets		(1,390)		(2,093)
Insurance recovery		0		0
Operating income	36,010	25,408	100,155	100,376
Operating Segments [Member] | Industrial Metals [Member]
Summary of segment information [Abstract]
Net sales	135,443	158,709	434,037	511,932
Cost of goods sold	117,893	141,435	372,542	445,259
Depreciation and amortization	1,836	1,864	5,518	5,715
Selling, general, and administrative expense	3,115	3,086	9,280	9,908
Gain on sale of assets		(1,301)		(1,301)
Insurance recovery		(1,486)		(1,486)
Operating income	12,599	15,111	46,697	53,837
Operating Segments [Member] | Climate [Member]
Summary of segment information [Abstract]
Net sales	90,938	81,619	276,853	156,854
Cost of goods sold	70,523	66,832	212,201	124,806
Depreciation and amortization	2,491	2,123	6,932	3,371
Selling, general, and administrative expense	9,961	6,890	24,336	12,009
Gain on sale of assets		0		0
Insurance recovery		0		0
Operating income	7,963	5,774	33,384	16,668
Corporate and Eliminations [Member]
Summary of segment information [Abstract]
Net sales	(8,696)	(4,895)	(17,387)	(14,667)
Cost of goods sold	(8,046)	(4,485)	(18,160)	(14,509)
Depreciation and amortization	745	686	2,453	2,427
Selling, general, and administrative expense	8,925	11,526	31,602	32,229
Gain on sale of assets		0		3,060
Insurance recovery		0		0
Operating income	$ (10,320)	$ (12,622)	$ (33,282)	$ (37,874)