Comprehensive Income and Accumulated Other Comprehensive Income (Loss) - Summary of Effects of Reclassifications from Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	$ 52,524	$ 3,573	$ 89,145	$ 20,656
Income tax expense	(8,552)	(400)	(16,432)	(2,592)
Net income (loss) attributable to Belden stockholders	$ 43,764	$ (67,905)	72,430	$ (79,094)
Reclassification out of Accumulated Other Comprehensive Income | Pension and Other  Postretirement Benefit Plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax			2,000
Income tax expense			(473)
Net income (loss) attributable to Belden stockholders			1,527
Reclassification out of Accumulated Other Comprehensive Income | Actuarial losses
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other nonoperating expense (income)			1,944
Reclassification out of Accumulated Other Comprehensive Income | Prior service cost
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other nonoperating expense (income)			56
Reclassification out of Accumulated Other Comprehensive Income | Foreign Currency Translation Component | Grass Valley
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other nonoperating expense (income)			$ 1,000