Segment Information (Details) $ in Thousands	3 Months Ended			6 Months Ended		12 Months Ended
	Jul. 02, 2016 USD ($)	Apr. 02, 2016 Segment	Jun. 27, 2015 USD ($)	Jul. 02, 2016 USD ($)	Jun. 27, 2015 USD ($)	Dec. 26, 2015 USD ($) Segment
Segment Information [Abstract]
Number of reportable segments | Segment		3				2
Summary of segment information [Abstract]
Net sales	$ 544,071		$ 555,593	$ 1,076,880	$ 1,092,835
Cost of goods sold	456,060		470,365	902,702	931,199
Depreciation and amortization	9,061		8,188	17,981	16,041
Selling, general, and administrative expense	34,514		33,420	70,294	66,251
Gain on sale of assets	0		(15,376)	0	(15,376)
Severance	0		3,442	0	3,442
Operating income	44,436		55,554	85,903	91,278
Interest expense	(1,692)		(2,219)	(3,540)	(4,295)
Other income, net	515		265	760	370
Income before income taxes	43,259		53,600	83,123	87,353
Segment assets	1,420,475			1,420,475		$ 1,338,801
Piping Systems [Member]
Summary of segment information [Abstract]
Segment assets	863,138			863,138		811,343
Industrial Metals [Member]
Summary of segment information [Abstract]
Segment assets	160,655			160,655		153,102
Climate [Member]
Summary of segment information [Abstract]
Segment assets	66,383			66,383		61,672
General Corporate [Member]
Summary of segment information [Abstract]
Segment assets	330,299			330,299		$ 312,684
Operating Segments [Member] | Piping Systems [Member]
Summary of segment information [Abstract]
Net sales	388,662		379,750	757,552	741,232
Cost of goods sold	333,356		326,338	647,148	639,028
Depreciation and amortization	5,787		5,335	11,436	10,522
Selling, general, and administrative expense	16,560		16,776	34,850	34,122
Gain on sale of assets			(15,376)		(15,376)
Severance			3,442		3,442
Operating income	32,959		43,235	64,118	69,494
Operating Segments [Member] | Industrial Metals [Member]
Summary of segment information [Abstract]
Net sales	127,737		145,228	262,258	296,264
Cost of goods sold	104,874		120,808	214,103	248,532
Depreciation and amortization	2,120		1,643	4,255	3,298
Selling, general, and administrative expense	3,619		2,302	6,864	5,000
Gain on sale of assets			0		0
Severance			0		0
Operating income	17,124		20,475	37,036	39,434
Operating Segments [Member] | Climate [Member]
Summary of segment information [Abstract]
Net sales	31,359		31,498	62,065	57,309
Cost of goods sold	22,448		24,134	46,153	45,401
Depreciation and amortization	618		614	1,217	1,039
Selling, general, and administrative expense	2,456		2,500	4,979	4,354
Gain on sale of assets			0		0
Severance			0		0
Operating income	5,837		4,250	9,716	6,515
Corporate and Eliminations [Member]
Summary of segment information [Abstract]
Net sales	(3,687)		(883)	(4,995)	(1,970)
Cost of goods sold	(4,618)		(915)	(4,702)	(1,762)
Depreciation and amortization	536		596	1,073	1,182
Selling, general, and administrative expense	11,879		11,842	23,601	22,775
Gain on sale of assets			0		0
Severance			0		0
Operating income	$ (11,484)		$ (12,406)	$ (24,967)	$ (24,165)