Acquisitions - Schedule of Recognized Identified Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Apr. 04, 2021	Jan. 29, 2021	Dec. 31, 2020
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Goodwill	$ 1,284,913		$ 1,251,938
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract]
Long-term debt		$ 1,841
Post retirement benefits		2,917
OTN Systems N.V.
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Receivables		7,617
Inventories		12,805
Other current assets		5,240
Property, plant and equipment		602
Intangible assets		33,500
Goodwill		39,337
Operating lease right-of-use assets		2,250
Other long-lived assets		706
Total assets acquired		102,057
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract]
Accounts payable		5,931
Accrued liabilities		9,991
Deferred income taxes		5,372
Long-term operating lease liabilities		1,870
Other long-term liabilities		771
Total liabilities assumed		28,693
Net assets		73,364
Noncontrolling interests		20
Net assets attributable to Belden		$ 73,344