Acquisitions - Schedule of Pro Forma Information (Details) - OTN Systems - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Revenues	$ 2,409,851	$ 1,900,646
Net income (loss) attributable to Belden common stockholders	$ 65,377	$ (59,150)
Diluted income (loss) per share attributable to Belden common stockholders (in dollars per share)	$ 1.44	$ (1.32)