Comprehensive Income and Accumulated Other Comprehensive Income (Loss) - Schedule of Total Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 28, 2025	Sep. 29, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 28, 2025	Sep. 29, 2024
Equity [Abstract]
Net income	$ 56,690	$ 53,689	$ 49,034	$ 37,309	$ 169,633	$ 140,032
Cumulative gain (loss) translation adjustment	(8,838)	(29,859)			(86,305)	(13,653)
Adjustments to pension and postretirement liability, net of tax	212	(73)			633	(221)
Total comprehensive income	48,064	23,757			83,961	126,158
Less: Comprehensive loss attributable to noncontrolling interests	0	(3)			0	(17)
Comprehensive income attributable to Belden	$ 48,064	$ 23,760			$ 83,961	$ 126,175