SEGMENT INFORMATION - Schedule of Net Sales From External Customers by Product Category (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 27, 2025	Jun. 28, 2024	Jun. 27, 2025	Jun. 28, 2024
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 735,045	$ 822,364	$ 2,098,367	$ 2,413,756
Electrical
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	521,306	605,955	1,479,331	1,790,426
Electrical \| Metal Electrical Conduit and Fittings
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	121,118	137,057	335,189	423,993
Electrical \| Electrical Cable & Flexible Conduit
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	132,431	128,249	366,889	358,576
Electrical \| Plastic Pipe and Conduit
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	176,098	238,800	499,123	716,354
Electrical \| Other Electrical products
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	91,659	101,849	278,130	291,503
Safety & Infrastructure
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	213,739	216,409	619,036	623,330
Safety & Infrastructure \| Mechanical Pipe
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	82,830	92,052	219,619	265,416
Safety & Infrastructure \| Other Safety & Infrastructure products
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 130,909	$ 124,357	$ 399,417	$ 357,914