SEGMENT INFORMATION - Schedule of Net Sales From External Customers by Product Category (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 27, 2026	Mar. 28, 2025	Mar. 27, 2026	Mar. 28, 2025
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 731,377	$ 701,725	$ 1,386,925	$ 1,363,322
Electrical
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	532,452	492,670	1,001,998	958,025
Electrical \| Metal Electrical Conduit and Fittings
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	128,981	111,866	247,337	214,071
Electrical \| Electrical Cable & Flexible Conduit
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	125,078	124,991	235,969	234,457
Electrical \| Plastic Pipe and Conduit
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	149,484	160,464	287,597	323,026
Electrical \| Other Electrical products
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	128,909	95,349	231,095	186,471
Safety & Infrastructure
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	198,925	209,055	384,927	405,297
Safety & Infrastructure \| Mechanical Pipe
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	74,077	70,530	139,439	136,789
Safety & Infrastructure \| Other Safety & Infrastructure products
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 124,848	$ 138,527	$ 245,488	$ 268,508