SEGMENT INFORMATION - Schedule of Net Sales From External Customers by Product Category (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 28, 2025	Mar. 29, 2024	Mar. 28, 2025	Mar. 29, 2024
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 701,725	$ 792,911	$ 1,363,322	$ 1,591,392
Electrical
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	492,670	590,811	958,025	1,184,471
Electrical | Metal Electrical Conduit and Fittings
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	111,866	147,697	214,071	286,936
Electrical | Electrical Cable & Flexible Conduit
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	124,991	114,634	234,457	230,327
Electrical | Plastic Pipe and Conduit
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	160,464	233,713	323,026	477,554
Electrical | Other Electrical products
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	95,349	94,767	186,471	189,654
Safety & Infrastructure
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	209,055	202,100	405,297	406,921
Safety & Infrastructure | Mechanical Pipe
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	70,530	88,866	136,789	173,364
Safety & Infrastructure | Other Safety & Infrastructure products
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 138,525	$ 113,234	$ 268,508	$ 233,557