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		9 Months Ended
	Oct. 03, 2021	Sep. 27, 2020	Oct. 03, 2021	Sep. 27, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	$ 50,192	$ 21,200	$ 139,337	$ 41,856
Income tax expense	(8,875)	(631)	(25,307)	(3,223)
Net income (loss) attributable to Belden stockholders	$ 41,264	$ 16,996	113,694	$ (62,098)
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			2,993
Income tax expense			(708)
Net income (loss) attributable to Belden stockholders			2,285
Reclassification out of Accumulated Other Comprehensive Income | Actuarial losses
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other nonoperating expense (income)			2,910
Reclassification out of Accumulated Other Comprehensive Income | Prior service cost
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other nonoperating expense (income)			83
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