Comprehensive Income and Accumulated Other Comprehensive Income (Loss) - Components of Other Comprehensive Income (Loss), Net of Tax (Details) $ in Thousands	9 Months Ended
	Sep. 29, 2024 USD ($)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 1,166,257
Other comprehensive loss attributable to Belden before reclassifications	(13,653)
Amounts reclassified from accumulated other comprehensive loss	(221)
Net current period other comprehensive loss attributable to Belden	(13,874)
Ending balance	1,235,211
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(41,279)
Ending balance	(55,153)
Foreign Currency Translation Component
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(26,514)
Other comprehensive loss attributable to Belden before reclassifications	(13,653)
Amounts reclassified from accumulated other comprehensive loss	0
Net current period other comprehensive loss attributable to Belden	(13,653)
Ending balance	(40,167)
Pension and Other  Postretirement Benefit Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(14,765)
Other comprehensive loss attributable to Belden before reclassifications	0
Amounts reclassified from accumulated other comprehensive loss	(221)
Net current period other comprehensive loss attributable to Belden	(221)
Ending balance	$ (14,986)